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1. An Enigmatic PeVatron in an Area around H ii Region G35.6−0.5

Author

Zhen Cao, F. Aharonian, Axikegu, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, W. Bian, A. V. Bukevich, Q. Cao, W. Y. Cao, Zhe Cao, J. Chang, J. F. Chang, A. M. Chen, B. Q. Chen, E. S. Chen, H. X. Chen, Liang Chen, Lin Chen, Long Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, M. C. Chu, M. Y. Cui, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, Danzengluobu, X. Q. Dong, K. K. Duan, J. H. Fan, Y. Z. Fan, J. Fang, J. H. Fang, K. Fang, C. F. Feng, H. Feng, L. Feng, S. H. Feng, X. T. Feng, Y. Feng, Y. L. Feng, S. Gabici, B. Gao, C. D. Gao, Q. Gao, W. Gao, W. K. Gao, M. M. Ge, T. T. Ge, L. S. Geng, G. Giacinti, G. H. Gong, Q. B. Gou, M. H. Gu, F. L. Guo, J. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, O. A. Hannuksela, M. Hasan, H. H. He, H. N. He, J. Y. He, Y. He, Y. K. Hor, B. W. Hou, C. Hou, X. Hou, H. B. Hu, Q. Hu, S. C. Hu, C. Huang, D. H. Huang, T. Q. Huang, W. J. Huang, X. T. Huang, X. Y. Huang, Y. Huang, Y. Y. Huang, X. L. Ji, H. Y. Jia, K. Jia, H. B. Jiang, K. Jiang, X. W. Jiang, Z. J. Jiang, M. Jin, M. M. Kang, I. Karpikov, D. Khangulyan, D. Kuleshov, K. Kurinov, B. B. Li, C. M. Li, Cheng Li, Cong Li, D. Li, F. Li, H. B. Li, H. C. Li, Jian Li, Jie Li, K. Li, S. D. Li, W. L. Li, X. R. Li, Xin Li, Y. Z. Li, Zhe Li, Zhuo Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, D. B. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, M. Y. Liu, R. Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y. N. Liu, Q. Luo, Y. Luo, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, Z. Min, W. Mitthumsiri, H. J. Mu, Y. C. Nan, A. Neronov, K. C. Y. Ng, L. J. Ou, P. Pattarakijwanich, Z. Y. Pei, J. C. Qi, M. Y. Qi, B. Q. Qiao, J. J. Qin, A. Raza, D. Ruffolo, A. Sáiz, M. Saeed, D. Semikoz, L. Shao, O. Shchegolev, X. D. Sheng, F. W. Shu, H. C. Song, Yu. V. Stenkin, V. Stepanov, Y. Su, D. X. Sun, Q. N. Sun, X. N. Sun, Z. B. Sun, J. Takata, P. H. T. Tam, Q. W. Tang, R. Tang, Z. B. Tang, W. W. Tian, L. H. Wan, C. Wang, C. B. Wang, G. W. Wang, H. G. Wang, H. H. Wang, J. C. Wang, Kai Wang, L. P. Wang, L. Y. Wang, P. H. Wang, R. Wang, W. Wang, X. G. Wang, X. Y. Wang, Y. Wang, Y. D. Wang, Y. J. Wang, Z. H. Wang, Z. X. Wang, Zhen Wang, Zheng Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, Q. W. Wu, S. Wu, X. F. Wu, Y. S. Wu, S. Q. Xi, J. Xia, G. M. Xiang, D. X. Xiao, G. Xiao, Y. L. Xin, Y. Xing, D. R. Xiong, Z. Xiong, D. L. Xu, R. F. Xu, R. X. Xu, W. L. Xu, L. Xue, D. H. Yan, J. Z. Yan, T. Yan, C. W. Yang, C. Y. Yang, F. Yang, F. F. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, W. X. Yang, Y. H. Yao, Z. G. Yao, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. Yue, H. D. Zeng, T. X. Zeng, W. Zeng, M. Zha, B. B. Zhang, F. Zhang, H. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, Li Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. B. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. F. Zhang, Yi Zhang, Yong Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, X. H. Zhao, F. Zheng, W. J. Zhong, B. Zhou, H. Zhou, J. N. Zhou, M. Zhou, P. Zhou, R. Zhou, X. X. Zhou, B. Y. Zhu, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, Y. C. Zou, X. Zuo, and (The LHAASO Collaboration)

Subjects
Gamma-rays, Gamma-ray sources, H II regions, Supernova remnants, Astrophysics, QB460-466
Abstract

Identifying Galactic PeVatrons (PeV particle accelerators) from ultrahigh-energy (UHE, >100 TeV) γ -ray sources plays a crucial role in revealing the origin of Galactic cosmic rays. The UHE source 1LHAASO J1857+0203u is suggested to be associated with HESS J1858+020, which may be attributed to the possible PeVatron candidate supernova remnant (SNR) G35.6−0.4 or H ii region G35.6−0.5. We perform detailed analysis on the very-high-energy and UHE γ -ray emissions toward this region with data from the Large High Altitude Air Shower Observatory (LHAASO). 1LHAASO J1857+0203u is detected with a significance of 11.6 σ above 100 TeV, indicating the presence of a PeVatron. It has an extent of ∼0 $\mathop{.}\limits^{\unicode{x000B0}}$ 18 with a power-law (PL) spectral index of ∼2.5 at 1–25 TeV and pointlike emission with a PL spectral index of ∼3.2 above 25 TeV. Using archival CO and H i data, we identify some molecular and atomic clouds that may be associated with the TeV γ -ray emissions. Our modeling indicates that the TeV γ -ray emissions are unlikely to arise from clouds illuminated by the protons that escaped from SNR G35.6−0.4. In the scenario in which H ii region G35.6−0.5 could accelerate particles to the UHE band, the observed GeV–TeV γ -ray emission could be well explained by a hadronic model with a PL spectral index of ∼2.0 and cutoff energy of ∼450 TeV. However, an origin in an evolved pulsar wind nebula cannot be ruled out.

Published
2025
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2. Discovery of Very High Energy Gamma-Ray Emissions from the Low-luminosity AGN NGC 4278 by LHAASO

Author

Zhen Cao, F. Aharonian, Axikegu, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, W. Bian, A. V. Bukevich, Q. Cao, W. Y. Cao, Zhe Cao, J. Chang, J. F. Chang, A. M. Chen, E. S. Chen, H. X. Chen, Liang Chen, Lin Chen, Long Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, M. Y. Cui, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, Danzengluobu, X. Q. Dong, K. K. Duan, J. H. Fan, Y. Z. Fan, J. Fang, J. H. Fang, K. Fang, C. F. Feng, H. Feng, L. Feng, S. H. Feng, X. T. Feng, Y. Feng, Y. L. Feng, S. Gabici, B. Gao, C. D. Gao, Q. Gao, W. Gao, W. K. Gao, M. M. Ge, L. S. Geng, G. Giacinti, G. H. Gong, Q. B. Gou, M. H. Gu, F. L. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, M. Hasan, H. H. He, H. N. He, J. Y. He, Y. He, Y. K. Hor, B. W. Hou, C. Hou, X. Hou, H. B. Hu, Q. Hu, S. C. Hu, D. H. Huang, T. Q. Huang, W. J. Huang, X. T. Huang, X. Y. Huang, Y. Huang, X. L. Ji, H. Y. Jia, K. Jia, K. Jiang, X. W. Jiang, Z. J. Jiang, M. Jin, M. M. Kang, I. Karpikov, D. Kuleshov, K. Kurinov, B. B. Li, C. M. Li, Cheng Li, Cong Li, D. Li, F. Li, H. B. Li, H. C. Li, Jian Li, Jie Li, K. Li, S. D. Li, W. L. Li, X. R. Li, Xin Li, Y. Z. Li, Zhe Li, Zhuo Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, D. B. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. Liu, Y. N. Liu, Q. Luo, Y. Luo, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, Z. Min, W. Mitthumsiri, H. J. Mu, Y. C. Nan, A. Neronov, L. J. Ou, P. Pattarakijwanich, Z. Y. Pei, J. C. Qi, M. Y. Qi, B. Q. Qiao, J. J. Qin, A. Raza, D. Ruffolo, A. Sáiz, M. Saeed, D. Semikoz, L. Shao, O. Shchegolev, X. D. Sheng, F. W. Shu, H. C. Song, Yu. V. Stenkin, V. Stepanov, Y. Su, D. X. Sun, Q. N. Sun, X. N. Sun, Z. B. Sun, J. Takata, P. H. T. Tam, Q. W. Tang, R. Tang, Z. B. Tang, W. W. Tian, C. Wang, C. B. Wang, G. W. Wang, H. G. Wang, H. H. Wang, J. C. Wang, Kai Wang, L. P. Wang, L. Y. Wang, P. H. Wang, R. Wang, W. Wang, X. G. Wang, X. Y. Wang, Y. Wang, Y. D. Wang, Y. J. Wang, Z. H. Wang, Z. X. Wang, Zhen Wang, Zheng Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, Q. W. Wu, S. Wu, X. F. Wu, Y. S. Wu, S. Q. Xi, J. Xia, G. M. Xiang, D. X. Xiao, G. Xiao, Y. L. Xin, Y. Xing, D. R. Xiong, Z. Xiong, D. L. Xu, R. F. Xu, R. X. Xu, W. L. Xu, L. Xue, D. H. Yan, J. Z. Yan, T. Yan, C. W. Yang, C. Y. Yang, F. Yang, F. F. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, W. X. Yang, Y. H. Yao, Z. G. Yao, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. Yue, H. D. Zeng, T. X. Zeng, W. Zeng, M. Zha, B. B. Zhang, F. Zhang, H. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, Li Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. B. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. F. Zhang, Yi Zhang, Yong Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, X. H. Zhao, F. Zheng, W. J. Zhong, B. Zhou, H. Zhou, J. N. Zhou, M. Zhou, P. Zhou, R. Zhou, X. X. Zhou, B. Y. Zhu, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, Y. C. Zou, X. Zuo, and The LHAASO Collaboration

Subjects
High energy astrophysics, Gamma-ray astronomy, Low-luminosity active galactic nuclei, LINER galaxies, Blazars, Fanaroff-Riley radio galaxies, Astrophysics, QB460-466
Abstract

The first source catalog of the Large High Altitude Air Shower Observatory (LHAASO) reported the detection of a very high energy gamma-ray source, 1LHAASO J1219+2915. This Letter presents a further detailed study of the spectral and temporal behavior of this pointlike source. The best-fit position of the TeV source (R.A. = 185.°05 ± 0.°04, decl. = 29.°25 ± 0.°03) is compatible with NGC 4278 within ∼0.°03. Variation analysis shows an indication of variability on a timescale of a few months in the TeV band, which is consistent with low-frequency observations. Based on these observations, we report the detection of TeV γ -ray emissions from this low-luminosity active galactic nucleus. The observation by LHAASO's Water Cherenkov Detector Array during the active period has a significance level of 8.8 σ with a best-fit photon spectral index Γ = 2.56 ± 0.14 and a flux f _1–10 TeV = (7.0 ± 1.1 _sta ± 0.35 _syst ) × 10 ^−13 photons cm ^−2 s ^−1 , or approximately 5% of the Crab Nebula. The discovery of VHE gamma-ray emission from NGC 4278 indicates that compact, weak radio jets can efficiently accelerate particles and emit TeV photons.

Published
2024
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3. Detection of Very High-energy Gamma-Ray Emission from the Radio Galaxy M87 with LHAASO

Author

Zhen Cao, F. Aharonian, Axikegu, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, W. Bian, A. V. Bukevich, Q. Cao, W. Y. Cao, Zhe Cao, J. Chang, J. F. Chang, A. M. Chen, E. S. Chen, H. X. Chen, Liang Chen, Lin Chen, Long Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, M. C. Chu, M. Y. Cui, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, Danzengluobu, X. Q. Dong, K. K. Duan, J. H. Fan, Y. Z. Fan, J. Fang, J. H. Fang, K. Fang, C. F. Feng, H. Feng, L. Feng, S. H. Feng, X. T. Feng, Y. Feng, Y. L. Feng, S. Gabici, B. Gao, C. D. Gao, Q. Gao, W. Gao, W. K. Gao, M. M. Ge, T. T. Ge, L. S. Geng, G. Giacinti, G. H. Gong, Q. B. Gou, M. H. Gu, F. L. Guo, J. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, O. A. Hannuksela, M. Hasan, H. H. He, H. N. He, J. Y. He, Y. He, Y. K. Hor, B. W. Hou, C. Hou, X. Hou, H. B. Hu, Q. Hu, S. C. Hu, C. Huang, D. H. Huang, T. Q. Huang, W. J. Huang, X. T. Huang, X. Y. Huang, Y. Huang, Y. Y. Huang, X. L. Ji, H. Y. Jia, K. Jia, H. B. Jiang, K. Jiang, X. W. Jiang, Z. J. Jiang, M. Jin, M. M. Kang, I. Karpikov, D. Khangulyan, D. Kuleshov, K. Kurinov, B. B. Li, C. M. Li, Cheng Li, Cong Li, D. Li, F. Li, H. B. Li, H. C. Li, Jian Li, Jie Li, K. Li, S. D. Li, W. L. Li, X. R. Li, Xin Li, Y. Z. Li, Zhe Li, Zhuo Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, D. B. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. Liu, Y. N. Liu, Q. Luo, Y. Luo, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, Z. Min, W. Mitthumsiri, H. J. Mu, Y. C. Nan, A. Neronov, K. C. Y. Ng, L. J. Ou, P. Pattarakijwanich, Z. Y. Pei, J. C. Qi, M. Y. Qi, B. Q. Qiao, J. J. Qin, A. Raza, D. Ruffolo, A. Sáiz, M. Saeed, D. Semikoz, L. Shao, O. Shchegolev, X. D. Sheng, F. W. Shu, H. C. Song, Yu. V. Stenkin, V. Stepanov, Y. Su, D. X. Sun, Q. N. Sun, X. N. Sun, Z. B. Sun, J. Takata, P. H. T. Tam, Q. W. Tang, R. Tang, Z. B. Tang, W. W. Tian, L. H. Wan, C. Wang, C. B. Wang, G. W. Wang, H. G. Wang, H. H. Wang, J. C. Wang, Kai Wang, L. P. Wang, L. Y. Wang, P. H. Wang, R. Wang, W. Wang, X. G. Wang, X. Y. Wang, Y. Wang, Y. D. Wang, Y. J. Wang, Z. H. Wang, Z. X. Wang, Zhen Wang, Zheng Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, Q. W. Wu, S. Wu, X. F. Wu, Y. S. Wu, S. Q. Xi, J. Xia, G. M. Xiang, D. X. Xiao, G. Xiao, Y. L. Xin, Y. Xing, D. R. Xiong, Z. Xiong, D. L. Xu, R. F. Xu, R. X. Xu, W. L. Xu, L. Xue, D. H. Yan, J. Z. Yan, T. Yan, C. W. Yang, C. Y. Yang, F. Yang, F. F. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, W. X. Yang, Y. H. Yao, Z. G. Yao, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. Yue, H. D. Zeng, T. X. Zeng, W. Zeng, M. Zha, B. B. Zhang, F. Zhang, H. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, Li Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. B. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. F. Zhang, Yi Zhang, Yong Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, X. H. Zhao, F. Zheng, W. J. Zhong, B. Zhou, H. Zhou, J. N. Zhou, M. Zhou, P. Zhou, R. Zhou, X. X. Zhou, B. Y. Zhu, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, Y. C. Zou, and X. Zuo

Subjects
Active galactic nuclei, High energy astrophysics, Astrophysics, QB460-466
Abstract

The nearby radio galaxy M87 is a very high-energy (VHE) gamma-ray emitter established by observations with ground-based gamma-ray detectors. Here we report the long-term monitoring of M87 from 2021 to 2024 with the Large High Altitude Air Shower Observatory (LHAASO). M87 has been detected by LHAASO with a statistical significance ∼ 9 σ . The observed energy spectrum extends to 20 TeV, with a possible hardening at ∼20 TeV and then a clear softening at higher energies. Assuming that the intrinsic spectrum is described by a single power law up to 20 TeV, a tight upper bound on the extragalactic background light intensity is obtained. A strong VHE flare lasting 8 days, with a rise time of ${\tau }_{r}^{\mathrm{rise}}=1.05\pm 0.49$ days and decay time of ${\tau }_{d}^{\mathrm{decay}}=2.17\pm 0.58$ days, was found in early 2022. A possible GeV flare is seen also in Fermi Large Area Telescope data during the VHE flare period. The variability time as short as 1 day seen in the LHAASO data suggests a compact emission region with a size of ∼3 × 10 ^15 δ cm ( δ being the Doppler factor of the emitting region), corresponding to a few Schwarzschild radii of the central supermassive black hole in M87. The continuous monitoring of the source reveals a duty cycle of ∼1% for VHE flares with a flux above 10 ^−11 erg cm ^−2 s ^−1 .

Published
2024
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4. The First LHAASO Catalog of Gamma-Ray Sources

Author

Zhen Cao, F. Aharonian, Q. An, Axikegu, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, J. T. Cai, Q. Cao, W. Y. Cao, Zhe Cao, J. Chang, J. F. Chang, A. M. Chen, E. S. Chen, Liang Chen, Lin Chen, Long Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, M. Y. Cui, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, Danzengluobu, D. della Volpe, X. Q. Dong, K. K. Duan, J. H. Fan, Y. Z. Fan, J. Fang, K. Fang, C. F. Feng, L. Feng, S. H. Feng, X. T. Feng, Y. L. Feng, S. Gabici, B. Gao, C. D. Gao, L. Q. Gao, Q. Gao, W. Gao, W. K. Gao, M. M. Ge, L. S. Geng, G. Giacinti, G. H. Gong, Q. B. Gou, M. H. Gu, F. L. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, H. H. He, H. N. He, J. Y. He, X. B. He, Y. He, M. Heller, Y. K. Hor, B. W. Hou, C. Hou, X. Hou, H. B. Hu, Q. Hu, S. C. Hu, D. H. Huang, T. Q. Huang, W. J. Huang, X. T. Huang, X. Y. Huang, Y. Huang, Z. C. Huang, X. L. Ji, H. Y. Jia, K. Jia, K. Jiang, X. W. Jiang, Z. J. Jiang, M. Jin, M. M. Kang, T. Ke, D. Kuleshov, K. Kurinov, B. B. Li, Cheng Li, Cong Li, D. Li, F. Li, H. B. Li, H. C. Li, H. Y. Li, J. Li, Jian Li, Jie Li, K. Li, W. L. Li, X. R. Li, Xin Li, Y. Z. Li, Zhe Li, Zhuo Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, J. Y. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. Liu, Y. N. Liu, R. Lu, Q. Luo, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, Z. Min, W. Mitthumsiri, H. J. Mu, Y. C. Nan, A. Neronov, Z. W. Ou, B. Y. Pang, P. Pattarakijwanich, Z. Y. Pei, M. Y. Qi, Y. Q. Qi, B. Q. Qiao, J. J. Qin, D. Ruffolo, A. Sáiz, D. Semikoz, C. Y. Shao, L. Shao, O. Shchegolev, X. D. Sheng, F. W. Shu, H. C. Song, Yu. V. Stenkin, V. Stepanov, Y. Su, Q. N. Sun, X. N. Sun, Z. B. Sun, P. H. T. Tam, Q. W. Tang, Z. B. Tang, W. W. Tian, C. Wang, C. B. Wang, G. W. Wang, H. G. Wang, H. H. Wang, J. C. Wang, K. Wang, L. P. Wang, L. Y. Wang, P. H. Wang, R. Wang, W. Wang, X. G. Wang, X. Y. Wang, Y. Wang, Y. D. Wang, Y. J. Wang, Z. H. Wang, Z. X. Wang, Zhen Wang, Zheng Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, S. Wu, X. F. Wu, Y. S. Wu, S. Q. Xi, J. Xia, J. J. Xia, G. M. Xiang, D. X. Xiao, G. Xiao, G. G. Xin, Y. L. Xin, Y. Xing, Z. Xiong, D. L. Xu, R. F. Xu, R. X. Xu, W. L. Xu, L. Xue, D. H. Yan, J. Z. Yan, T. Yan, C. W. Yang, F. Yang, F. F. Yang, H. W. Yang, J. Y. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, S. B. Yang, Y. H. Yao, Z. G. Yao, Y. M. Ye, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. Yue, H. D. Zeng, T. X. Zeng, W. Zeng, M. Zha, B. B. Zhang, F. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, L. X. Zhang, Li Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. B. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. F. Zhang, Yi Zhang, Yong Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, F. Zheng, B. Zhou, H. Zhou, J. N. Zhou, M. Zhou, P. Zhou, R. Zhou, X. X. Zhou, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, X. Zuo, and (The LHAASO Collaboration)

Subjects
Gamma-ray astronomy, Gamma-ray observatories, Catalogs, Astrophysics, QB460-466
Abstract

We present the first catalog of very-high-energy and ultra-high-energy gamma-ray sources detected by the Large High Altitude Air Shower Observatory. The catalog was compiled using 508 days of data collected by the Water Cherenkov Detector Array from 2021 March to 2022 September and 933 days of data recorded by the Kilometer Squared Array from 2020 January to 2022 September. This catalog represents the main result from the most sensitive large coverage gamma-ray survey of the sky above 1 TeV, covering decl. from −20° to 80°. In total, the catalog contains 90 sources with an extended size smaller than 2° and a significance of detection at >5 σ . Based on our source association criteria, 32 new TeV sources are proposed in this study. Among the 90 sources, 43 sources are detected with ultra-high energy ( E > 100 TeV) emission at >4 σ significance level. We provide the position, extension, and spectral characteristics of all the sources in this catalog.

Published
2024
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5. Construction and on-site performance of the LHAASO WFCTA camera

Author

F. Aharonian, Q. An, Axikegu, L. X. Bai, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, H. Cai, J. T. Cai, Z. Cao, J. Chang, J. F. Chang, X. C. Chang, B. M. Chen, J. Chen, L. Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, X. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, Danzengluobu, D. della Volpe, B. D’Ettorre Piazzoli, X. J. Dong, J. H. Fan, Y. Z. Fan, Z. X. Fan, J. Fang, K. Fang, C. F. Feng, L. Feng, S. H. Feng, Y. L. Feng, B. Gao, C. D. Gao, Q. Gao, W. Gao, M. M. Ge, L. S. Geng, G. H. Gong, Q. B. Gou, M. H. Gu, J. G. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, H. H. He, H. N. He, J. C. He, S. L. He, X. B. He, Y. He, M. Heller, Y. K. Hor, C. Hou, X. Hou, H. B. Hu, S. Hu, S. C. Hu, X. J. Hu, D. H. Huang, Q. L. Huang, W. H. Huang, X. T. Huang, Z. C. Huang, F. Ji, X. L. Ji, H. Y. Jia, K. Jiang, Z. J. Jiang, C. Jin, D. Kuleshov, K. Levochkin, B. B. Li, C. Li, F. Li, H. B. Li, H. C. Li, H. Y. Li, J. Li, K. Li, W. L. Li, X. Li, X. R. Li, Y. Li, Y. Z. Li, Z. Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, J. S. Liu, J. Y. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. N. Liu, Z. X. Liu, W. J. Long, R. Lu, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, A. Masood, W. Mitthumsiri, T. Montaruli, Y. C. Nan, B. Y. Pang, P. Pattarakijwanich, Z. Y. Pei, M. Y. Qi, D. Ruffolo, V. Rulev, A. Sáiz, L. Shao, O. Shchegolev, X. D. Sheng, J. R. Shi, H. C. Song, Yu. V. Stenkin, V. Stepanov, Q. N. Sun, X. N. Sun, Z. B. Sun, P. H. T. Tam, Z. B. Tang, W. W. Tian, B. D. Wang, C. Wang, H. Wang, H. G. Wang, J. C. Wang, J. S. Wang, L. P. Wang, L. Y. Wang, R. N. Wang, W. Wang, X. G. Wang, X. J. Wang, X. Y. Wang, Y. D. Wang, Y. J. Wang, Y. P. Wang, Z. Wang, Z. H. Wang, Z. X. Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, S. Wu, W. X. Wu, X. F. Wu, S. Q. Xi, J. Xia, J. J. Xia, G. M. Xiang, G. Xiao, H. B. Xiao, G. G. Xin, Y. L. Xin, Y. Xing, D. L. Xu, R. X. Xu, L. Xue, D. H. Yan, C. W. Yang, F. F. Yang, J. Y. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, S. B. Yang, Y. H. Yao, Z. G. Yao, Y. M. Ye, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. D. Zeng, T. X. Zeng, W. Zeng, Z. K. Zeng, M. Zha, X. X. Zhai, B. B. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, J. W. Zhang, L. Zhang, L. X. Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. R. Zhang, S S. Zhang, X. Zhang, X. P. Zhang, Y. Zhang, Y. F. Zhang, Y. L. Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J. N. Zhou, P. Zhou, R. Zhou, X. X. Zhou, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, X. Zuo, and The LHAASO Collaboration

Subjects
Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract The focal plane camera is the core component of the Wide Field-of-view Cherenkov/fluorescence Telescope Array (WFCTA) of the Large High-Altitude Air Shower Observatory (LHAASO). Because of the capability of working under moonlight without aging, silicon photomultipliers (SiPM) have been proven to be not only an alternative but also an improvement to conventional photomultiplier tubes (PMT) in this application. Eighteen SiPM-based cameras with square light funnels have been built for WFCTA. The telescopes have collected more than 100 million cosmic ray events and preliminary results indicate that these cameras are capable of working under moonlight. The characteristics of the light funnels and SiPMs pose challenges (e.g. dynamic range, dark count rate, assembly techniques). In this paper, we present the design features, manufacturing techniques and performances of these cameras. Finally, the test facilities, the test methods and results of SiPMs in the cameras are reported here.

Published
2021
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6. A dynamic range extension system for LHAASO WCDA-1

Author

F. Aharonian, Q. An, null Axikegu, L. X. Bai, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, H. Cai, J. T. Cai, Z. Cao, J. Chang, J. F. Chang, X. C. Chang, B. M. Chen, J. Chen, L. Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, X. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, null Danzengluobu, D. della Volpe, B. D’Ettorre Piazzoli, X. J. Dong, J. H. Fan, Y. Z. Fan, Z. X. Fan, J. Fang, K. Fang, C. F. Feng, L. Feng, S. H. Feng, Y. L. Feng, B. Gao, C. D. Gao, Q. Gao, W. Gao, M. M. Ge, L. S. Geng, G. H. Gong, Q. B. Gou, M. H. Gu, J. G. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, H. H. He, H. N. He, J. C. He, S. L. He, X. B. He, Y. He, M. Heller, Y. K. Hor, C. Hou, X. Hou, H. B. Hu, S. Hu, S. C. Hu, X. J. Hu, D. H. Huang, Q. L. Huang, W. H. Huang, X. T. Huang, Y. Huang, Z. C. Huang, F. Ji, X. L. Ji, H. Y. Jia, K. Jiang, Z. J. Jiang, C. Jin, D. Kuleshov, K. Levochkin, B. B. Li, C. Li, F. Li, H. B. Li, H. C. Li, H. Y. Li, J. Li, K. Li, W. L. Li, X. Li, X. R. Li, Y. Li, Y. Z. Li, Z. Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, J. S. Liu, J. Y. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. N. Liu, Z. X. Liu, W. J. Long, R. Lu, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, A. Masood, W. Mitthumsiri, T. Montaruli, Y. C. Nan, B. Y. Pang, P. Pattarakijwanich, Z. Y. Pei, M. Y. Qi, D. Ruffolo, V. Rulev, A. Sáiz, L. Shao, O. Shchegolev, X. D. Sheng, J. R. Shi, H. C. Song, Yu. V. Stenkin, V. Stepanov, Q. N. Sun, X. N. Sun, Z. B. Sun, P. H. T. Tam, Z. B. Tang, W. W. Tian, B. D. Wang, C. Wang, H. Wang, H. G. Wang, J. C. Wang, J. S. Wang, L. P. Wang, L. Y. Wang, R. N. Wang, W. Wang, X. G. Wang, X. J. Wang, X. Y. Wang, Y. D. Wang, Y. J. Wang, Y. P. Wang, Z. Wang, Z. H. Wang, Z. X. Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, S. Wu, W. X. Wu, X. F. Wu, S. Q. Xi, J. Xia, J. J. Xia, G. M. Xiang, G. Xiao, H. B. Xiao, G. G. Xin, Y. L. Xin, Y. Xing, D. L. Xu, R. X. Xu, L. Xue, D. H. Yan, C. W. Yang, F. F. Yang, J. Y. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, S. B. Yang, Y. H. Yao, Z. G. Yao, Y. M. Ye, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. D. Zeng, T. X. Zeng, W. Zeng, Z. K. Zeng, M. Zha, X. X. Zhai, B. B. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, J. W. Zhang, L. Zhang, L. X. Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. Zhang, Y. F. Zhang, Y. L. Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J. N. Zhou, P. Zhou, R. Zhou, X. X. Zhou, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, and X. Zuo

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Dynamic range, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Cosmic ray, Extension (predicate logic), Measure (mathematics), Effective nuclear charge, Nuclear physics, Air shower, Nuclear Energy and Engineering, Orders of magnitude (time), Energy (signal processing)
Abstract

The main scientific goal of LHAASO-WCDA is to survey gamma-ray sources with energy from 100 GeV to 30 TeV. To observe high-energy shower events, especially to measure the energy spectrum of cosmic rays from 100 TeV to 10 PeV, a dynamic range extension system (WCDA++) is designed to use a 1.5-inch PMT with a dynamic range of four orders of magnitude for each cell in WCDA-1. The dynamic range is extended by using these PMTs to measure the effective charge density in the core region of air shower events, which is an important parameter for identifying the composition of primary particles. The system has been running for more than one year. In this paper, the details of the design and performance of WCDA++ are presented.

Published
2021
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7. Constraints on heavy decaying dark matter from 570 days of LHAASO observations

Author

Zhen, Cao, F, Aharonian, Q, An, Axikegu, L X, Bai, Y X, Bai, Y W, Bao, D, Bastieri, X J, Bi, Y J, Bi, J T, Cai, Zhe, Cao, J, Chang, J F, Chang, E S, Chen, Liang, Chen, Long, Chen, M J, Chen, M L, Chen, Q H, Chen, S H, Chen, S Z, Chen, T L, Chen, Y, Chen, H L, Cheng, N, Cheng, Y D, Cheng, S W, Cui, X H, Cui, Y D, Cui, B, D'Ettorre Piazzoli, B Z, Dai, H L, Dai, Z G, Dai, Danzengluobu, D, Della Volpe, K K, Duan, J H, Fan, Y Z, Fan, Z X, Fan, J, Fang, K, Fang, C F, Feng, L, Feng, S H, Feng, X T, Feng, Y L, Feng, B, Gao, C D, Gao, L Q, Gao, Q, Gao, W, Gao, W K, Gao, M M, Ge, L S, Geng, G H, Gong, Q B, Gou, M H, Gu, F L, Guo, J G, Guo, X L, Guo, Y Q, Guo, Y Y, Guo, Y A, Han, H H, He, H N, He, S L, He, X B, He, Y, He, M, Heller, Y K, Hor, C, Hou, X, Hou, H B, Hu, Q, Hu, S, Hu, S C, Hu, X J, Hu, D H, Huang, W H, Huang, X T, Huang, X Y, Huang, Y, Huang, Z C, Huang, X L, Ji, H Y, Jia, K, Jia, K, Jiang, Z J, Jiang, M, Jin, M M, Kang, T, Ke, D, Kuleshov, K, Levochkin, B B, Li, Cheng, Li, Cong, Li, F, Li, H B, Li, H C, Li, H Y, Li, J, Li, Jian, Li, Jie, Li, K, Li, W L, Li, X R, Li, Xin, Li, Y Z, Li, Zhe, Li, Zhuo, Li, E W, Liang, Y F, Liang, S J, Lin, B, Liu, C, Liu, D, Liu, H, Liu, H D, Liu, J, Liu, J L, Liu, J S, Liu, J Y, Liu, M Y, Liu, R Y, Liu, S M, Liu, W, Liu, Y, Liu, Y N, Liu, W J, Long, R, Lu, Q, Luo, H K, Lv, B Q, Ma, L L, Ma, X H, Ma, J R, Mao, A, Masood, Z, Min, W, Mitthumsiri, Y C, Nan, Z W, Ou, B Y, Pang, P, Pattarakijwanich, Z Y, Pei, M Y, Qi, Y Q, Qi, B Q, Qiao, J J, Qin, D, Ruffolo, A, Sáiz, C Y, Shao, L, Shao, O, Shchegolev, X D, Sheng, J Y, Shi, H C, Song, Yu V, Stenkin, V, Stepanov, Y, Su, Q N, Sun, X N, Sun, Z B, Sun, P H T, Tam, Z B, Tang, W W, Tian, B D, Wang, C, Wang, H, Wang, H G, Wang, J C, Wang, J S, Wang, L P, Wang, L Y, Wang, R, Wang, R N, Wang, W, Wang, X G, Wang, X Y, Wang, Y, Wang, Y D, Wang, Y J, Wang, Y P, Wang, Z H, Wang, Z X, Wang, Zhen, Wang, Zheng, Wang, D M, Wei, J J, Wei, Y J, Wei, T, Wen, C Y, Wu, H R, Wu, S, Wu, X F, Wu, Y S, Wu, S Q, Xi, J, Xia, J J, Xia, G M, Xiang, D X, Xiao, G, Xiao, G G, Xin, Y L, Xin, Y, Xing, Z, Xiong, D L, Xu, R X, Xu, L, Xue, D H, Yan, J Z, Yan, C W, Yang, F F, Yang, H W, Yang, J Y, Yang, L L, Yang, M J, Yang, R Z, Yang, S B, Yang, Y H, Yao, Z G, Yao, Y M, Ye, L Q, Yin, N, Yin, X H, You, Z Y, You, Y H, Yu, Q, Yuan, H, Yue, H D, Zeng, T X, Zeng, W, Zeng, Z K, Zeng, M, Zha, X X, Zhai, B B, Zhang, F, Zhang, H M, Zhang, H Y, Zhang, J L, Zhang, L X, Zhang, Li, Zhang, Lu, Zhang, P F, Zhang, P P, Zhang, R, Zhang, S B, Zhang, S R, Zhang, S S, Zhang, X, Zhang, X P, Zhang, Y F, Zhang, Y L, Zhang, Yi, Zhang, Yong, Zhang, B, Zhao, J, Zhao, L, Zhao, L Z, Zhao, S P, Zhao, F, Zheng, Y, Zheng, B, Zhou, H, Zhou, J N, Zhou, P, Zhou, R, Zhou, X X, Zhou, C G, Zhu, F R, Zhu, H, Zhu, K J, Zhu, X, Zuo, S, Ando, M, Chianese, D F G, Fiorillo, G, Miele, K C Y, Ng, and GRAPPA (ITFA, IoP, FNWI)

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), High Energy Physics - Phenomenology, Cosmology and Nongalactic Astrophysics (astro-ph.CO), High Energy Physics - Phenomenology (hep-ph), General Physics and Astronomy, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 105 and 109 GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

Published
2022

9. Ratios of helicity amplitudes for exclusive ρ0 electroproduction

Author

The HERMES Collaboration, A. Airapetian, N. Akopov, Z. Akopov, E. C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetisyan, S. Belostotski, N. Bianchi, H. P. Blok, A. Borissov, J. Bowles, V. Bryzgalov, J. Burns, M. Capiluppi, G. P. Capitani, E. Cisbani, G. Ciullo, M. Contalbrigo, P. F. Dalpiaz, W. Deconinck, R. De Leo, L. De Nardo, E. De Sanctis, M. Diefenthaler, P. Di Nezza, M. Düren, M. Ehrenfried, G. Elbakian, F. Ellinghaus, R. Fabbri, A. Fantoni, L. Felawka, S. Frullani, D. Gabbert, G. Gapienko, V. Gapienko, F. Garibaldi, G. Gavrilov, V. Gharibyan, F. Giordano, S. Gliske, M. Golembiovskaya, C. Hadjidakis, M. Hartig, D. Hasch, G. Hill, A. Hillenbrand, M. Hoek, Y. Holler, I. Hristova, Y. Imazu, A. Ivanilov, H. E. Jackson, H. S. Jo, S. Joosten, R. Kaiser, G. Karyan, T. Keri, E. Kinney, A. Kisselev, N. Kobayashi, V. Korotkov, V. Kozlov, P. Kravchenko, V. G. Krivokhijine, L. Lagamba, R. Lamb, L. Lapikás, I. Lehmann, P. Lenisa, L. A. Linden-Levy, A. López Ruiz, W. Lorenzon, X.-G. Lu, X.-R. Lu, B.-Q. Ma, D. Mahon, N. C. R. Makins, S. I. Manaenkov, L. Manfré, Y. Mao, B. Marianski, A. Martinez de la Ossa, H. Marukyan, C. A. Miller, Y. Miyachi, A. Movsisyan, V. Muccifora, M. Murray, A. Mussgiller, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W.-D. Nowak, L. L. Pappalardo, R. Perez-Benito, N. Pickert, P. E. Reimer, A. R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, J. Rubin, D. Ryckbosch, Y. Salomatin, F. Sanftl, A. Schäfer, G. Schnell, K. P. Schüler, B. Seitz, T.-A. Shibata, V. Shutov, M. Stancari, M. Statera, E. Steffens, J. J. M. Steijger, F. Stinzing, S. Taroian, A. Terkulov, A. Trzcinski, M. Tytgat, A. Vandenbroucke, Y. Van Haarlem, C. Van Hulse, D. Veretennikov, V. Vikhrov, I. Vilardi, S. Wang, S. Yaschenko, S. Yen, W. Yu, B. Zihlmann, and P. Zupranski

Subjects
Systematic Uncertainty, Amplitude Ratio, Total Uncertainty, Helicity Amplitude, ZEUS Collaboration, Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract Exclusive ρ 0-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV2

Published
2011
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10. Discovery of a new $\gamma$-ray source LHAASO J0341+5258 with emission up to 200TeV

Author

Zhengguo Cao, L. Feng, Xufang Li, Zebo Tang, Jun-Jie Wei, C. Y. Wu, Jia Zhang, L. X. Bai, Yi Zhang, H. K. Lv, Jixia Li, L. L. Yang, Z. X. Wang, M. Zha, Y. M. Ye, X. H. Ma, L. P. Wang, X. G. Wang, Donglian Xu, X. L. Guo, Y. A. Han, Binyu Zhao, Yun-Feng Liang, Houdun Zeng, Zhe Li, Y. Su, B. Z. Dai, Z. G. Dai, Jinmei Liu, B. D'Ettorre Piazzoli, Z. G. Yao, Y. Zheng, W. X. Wu, M. L. Chen, Jianeng Zhou, Hefan Li, W. Wang, P. Pattarakijwanich, Rong Xu, J. J. Xia, X. X. Zhai, J. Fang, F. R. Zhu, Qie Sun, Yi Chen, H. B. Li, G. M. Xiang, W. Liu, B. Y. Pang, S. Wu, X. L. Ji, R. Lu, K. Li, Y. J. Bi, H. D. Liu, Y. D. Cheng, Bo Zhang, L. Q. Yin, Hanzhong Zhang, C. X. Liu, D. della Volpe, Y. D. Cui, Kun Fang, Yugang Zhang, E. W. Liang, Ping Zhou, Z. J. Jiang, Y. J. Wei, J. Liu, Yong Zhang, Duo Yan, Yu. V. Stenkin, S. L. He, Y. P. Wang, Z. X. Liu, D. H. Huang, R. N. Wang, S. M. Liu, F. Ji, V. Rulev, Y. Z. Li, H. H. He, H. Zhu, C. Hou, Zheng Wang, B. Q. Ma, Y. C. Nan, L. Xue, Jun Liu, Lu Zhang, H. Y. Jia, D. M. Wei, V. I. Stepanov, E. S. Chen, Sina Chen, K. J. Zhu, Y. Q. Qi, Fulai Guo, J. Y. Shi, Minghui Liu, Yi Liu, J. B. Zhao, H. Wang, X. F. Wu, Zhen Wang, Z. X. Fan, Z. Y. You, Shi-Qi Hu, J. Y. Yang, N. Cheng, Z. K. Zeng, C. D. Gao, X. H. You, Long Gao, H. C. Song, Lei Zhao, D.A. Kuleshov, X. X. Zhou, Q. Yuan, B. M. Chen, Ruizhi Yang, X. N. Sun, Shengxue Zhang, Danzengluobu, J. F. Chang, S. P. Zhao, H. Liu, J.W. Xia, W. Gao, G. C. Xiao, Felix Aharonian, Xinbo He, K. Jiang, Pak-Hin Thomas Tam, H. C. Li, Y. Wang, Y. Z. Fan, Dong Liu, Y. W. Bao, P. F. Zhang, X. J. Bi, H. N. He, T. L. Chen, L. Z. Zhao, X. J. Hu, R. Zhou, Ying Zhang, Oleg Shchegolev, Junjie Mao, Y. Q. Guo, F. Y. Li, K. Levochkin, J. T. Cai, X. D. Sheng, Cong Li, X. Zuo, B. B. Li, Long Chen, Yunchao Liu, H. L. Dai, T. Wen, S. W. Cui, S. Z. Chen, David Ruffolo, Y. M. Xing, H. R. Wu, Liang Chen, Xiang-Kun Dong, S. Hu, J. Y. Liu, X. Y. Huang, P. P. Zhang, X. H. Cui, Minghao Qi, Z. B. Sun, Y. Bai, Z. Y. Pei, Cheng Guang Zhu, Yuan-Hao Wang, Zhuo Li, Warit Mitthumsiri, H. M. Zhang, Q. An, Y. H. Yao, W. H. Huang, H. Zhou, W. J. Long, Binbin Zhou, Li-Sheng Geng, R. Liu, Xiang Zhang, J. G. Guo, J. W. Zhang, S. R. Zhang, Wenwu Tian, L. L. Ma, Q. Gao, C. F. Feng, Jiangang He, J. S. Wang, Cunguo Wang, Y. L. Xin, Z. C. Huang, H. B. Hu, N. Yin, B. Q. Qiao, Xin Li, Cheng Li, Jiajun Qin, M. H. Gu, Boyang Wang, Rui Zhang, H. B. Xiao, W. Zeng, L. X. Zhang, S. H. Feng, M. M. Ge, Axikegu, Yonggang Wang, M. J. Chen, Zhao-Qi Wang, Y. Y. Guo, Li Zhang, G. H. Gong, Zhe Cao, Y. K. Hor, Y. H. Yu, T. Montaruli, Jian Wang, Chiming Jin, Z. Min, Xuelong Wang, G. G. Xin, Kai-Kai Duan, D. Bastieri, Y. L. Feng, T. Ke, S. J. Lin, X. T. Huang, L. Y. Wang, B. Liu, Jingzhi Yan, Bingshui Gao, Xiang-Yu Wang, Yulong Li, Tao Zeng, Xuliang Chen, Y. He, C. W. Yang, Jun-Hui Fan, Q. B. Gou, W. L. Li, D. X. Xiao, Qizhi Huang, J. Chen, Xiao-Hu Zhang, H. Cai, M. J. Yang, S. Q. Xi, Hong-Guang Wang, Alejandro Sáiz, Q. H. Chen, S. B. Yang, Fan Yang, A. Masood, F. Zheng, Lang Shao, and M. Heller

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Gamma ray, Flux, Astronomy and Astrophysics, Astrophysics, Galactic plane, Crab Nebula, Pulsar, Space and Planetary Science, Angular diameter, High Energy Physics::Experiment, Supernova remnant, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Galaxy Astrophysics
Abstract

We report the discovery of a new unidentified extended $\gamma$-ray source in the Galactic plane named LHAASO J0341+5258 with a pre-trial significance of 8.2 standard deviations above 25 TeV. The best fit position is R.A.$=55.34^{\circ}\pm0.11^{\circ}$ and Dec$=52.97^{\circ}\pm0.07^{\circ}$. The angular size of LHAASO J0341+5258 is $0.29^\circ \pm 0.06^\circ_{stat} \pm0.02^\circ_{sys}$. The flux above 25 TeV is about $20\%$ of the flux of Crab Nebula. Although a power-law fit of the spectrum from 10 TeV to 200 TeV with the photon index $\alpha=2.98 \pm 0.19_{stat} \pm 0.02_{sys}$ is not excluded, the LHAASO data together with the flux upper limit at 10 GeV set by the Fermi LAT observation, indicate a noticeable steepening of an initially hard power-law spectrum %($\alpha \leq 1.75$) spectrum with a cutoff at $\approx 50$ TeV. We briefly discuss the origin of UHE gamma-rays. The lack of an energetic pulsar and a young SNR inside or in the vicinity of LHAASO J0341+5258 challenge, but do not exclude both the leptonic and hadronic scenarios of gamma-ray production., Comment: Accepted by APJL

Published
2021

11. Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Author

Zhen, Cao, F, Aharonian, Q, An, Axikegu, L X, Bai, Y X, Bai, Y W, Bao, D, Bastieri, X J, Bi, Y J, Bi, H, Cai, J T, Cai, Zhe, Cao, J, Chang, J F, Chang, B M, Chen, E S, Chen, J, Chen, Liang, Chen, Long, Chen, M J, Chen, M L, Chen, Q H, Chen, S H, Chen, S Z, Chen, T L, Chen, X L, Chen, Y, Chen, N, Cheng, Y D, Cheng, S W, Cui, X H, Cui, Y D, Cui, B D'Ettorre, Piazzoli, B Z, Dai, H L, Dai, Z G, Dai, Danzengluobu, D, Della Volpe, X J, Dong, K K, Duan, J H, Fan, Y Z, Fan, Z X, Fan, J, Fang, K, Fang, C F, Feng, L, Feng, S H, Feng, Y L, Feng, B, Gao, C D, Gao, L Q, Gao, Q, Gao, W, Gao, M M, Ge, L S, Geng, G H, Gong, Q B, Gou, M H, Gu, F L, Guo, J G, Guo, X L, Guo, Y Q, Guo, Y Y, Guo, Y A, Han, H H, He, H N, He, J C, He, S L, He, X B, He, Y, He, M, Heller, Y K, Hor, C, Hou, X, Hou, H B, Hu, S, Hu, S C, Hu, X J, Hu, D H, Huang, Q L, Huang, W H, Huang, X T, Huang, X Y, Huang, Z C, Huang, F, Ji, X L, Ji, H Y, Jia, K, Jiang, Z J, Jiang, C, Jin, T, Ke, D, Kuleshov, K, Levochkin, B B, Li, Cheng, Li, Cong, Li, F, Li, H B, Li, H C, Li, H Y, Li, Jian, Li, Jie, Li, K, Li, W L, Li, X R, Li, Xin, Li, Y, Li, Y Z, Li, Zhe, Li, Zhuo, Li, E W, Liang, Y F, Liang, S J, Lin, B, Liu, C, Liu, D, Liu, H, Liu, H D, Liu, J, Liu, J L, Liu, J S, Liu, J Y, Liu, M Y, Liu, R Y, Liu, S M, Liu, W, Liu, Y, Liu, Y N, Liu, Z X, Liu, W J, Long, R, Lu, H K, Lv, B Q, Ma, L L, Ma, X H, Ma, J R, Mao, A, Masood, Z, Min, W, Mitthumsiri, T, Montaruli, Y C, Nan, B Y, Pang, P, Pattarakijwanich, Z Y, Pei, M Y, Qi, Y Q, Qi, B Q, Qiao, J J, Qin, D, Ruffolo, V, Rulev, A, Sáiz, L, Shao, O, Shchegolev, X D, Sheng, J R, Shi, H C, Song, Yu V, Stenkin, V, Stepanov, Y, Su, Q N, Sun, X N, Sun, Z B, Sun, P H T, Tam, Z B, Tang, W W, Tian, B D, Wang, C, Wang, H, Wang, H G, Wang, J C, Wang, J S, Wang, L P, Wang, L Y, Wang, R N, Wang, W, Wang, X G, Wang, X J, Wang, X Y, Wang, Y, Wang, Y D, Wang, Y J, Wang, Y P, Wang, Z H, Wang, Z X, Wang, Zhen, Wang, Zheng, Wang, D M, Wei, J J, Wei, Y J, Wei, T, Wen, C Y, Wu, H R, Wu, S, Wu, W X, Wu, X F, Wu, S Q, Xi, J, Xia, J J, Xia, G M, Xiang, D X, Xiao, G, Xiao, H B, Xiao, G G, Xin, Y L, Xin, Y, Xing, D L, Xu, R X, Xu, L, Xue, D H, Yan, J Z, Yan, C W, Yang, F F, Yang, J Y, Yang, L L, Yang, M J, Yang, R Z, Yang, S B, Yang, Y H, Yao, Z G, Yao, Y M, Ye, L Q, Yin, N, Yin, X H, You, Z Y, You, Y H, Yu, Q, Yuan, H D, Zeng, T X, Zeng, W, Zeng, Z K, Zeng, M, Zha, X X, Zhai, B B, Zhang, H M, Zhang, H Y, Zhang, J L, Zhang, J W, Zhang, L X, Zhang, Li, Zhang, Lu, Zhang, P F, Zhang, P P, Zhang, R, Zhang, S R, Zhang, S S, Zhang, X, Zhang, X P, Zhang, Y F, Zhang, Y L, Zhang, Yi, Zhang, Yong, Zhang, B, Zhao, J, Zhao, L, Zhao, L Z, Zhao, S P, Zhao, F, Zheng, Y, Zheng, B, Zhou, H, Zhou, J N, Zhou, P, Zhou, R, Zhou, X X, Zhou, C G, Zhu, F R, Zhu, H, Zhu, K J, Zhu, and X, Zuo

Subjects
General Physics and Astronomy
Abstract

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Published
2021

12. Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

Author

F, Aharonian, Q, An, Axikegu, L X, Bai, Y X, Bai, Y W, Bao, D, Bastieri, X J, Bi, Y J, Bi, H, Cai, J T, Cai, Z, Cao, J, Chang, J F, Chang, X C, Chang, B M, Chen, J, Chen, L, Chen, M J, Chen, M L, Chen, Q H, Chen, S H, Chen, S Z, Chen, T L, Chen, X L, Chen, Y, Chen, N, Cheng, Y D, Cheng, S W, Cui, X H, Cui, Y D, Cui, B Z, Dai, H L, Dai, Z G, Dai, Danzengluobu, D, Della Volpe, B, D'Ettorre Piazzoli, X J, Dong, J H, Fan, Y Z, Fan, Z X, Fan, J, Fang, K, Fang, C F, Feng, L, Feng, S H, Feng, Y L, Feng, B, Gao, C D, Gao, Q, Gao, W, Gao, M M, Ge, L S, Geng, G H, Gong, Q B, Gou, M H, Gu, J G, Guo, X L, Guo, Y Q, Guo, Y Y, Guo, Y A, Han, H H, He, H N, He, J C, He, S L, He, X B, He, Y, He, M, Heller, Y K, Hor, C, Hou, X, Hou, H B, Hu, S, Hu, S C, Hu, X J, Hu, D H, Huang, Q L, Huang, W H, Huang, X T, Huang, Z C, Huang, F, Ji, X L, Ji, H Y, Jia, K, Jiang, Z J, Jiang, C, Jin, D, Kuleshov, K, Levochkin, B B, Li, C, Li, F, Li, H B, Li, H C, Li, H Y, Li, J, Li, K, Li, W L, Li, X, Li, X R, Li, Y, Li, Y Z, Li, Z, Li, E W, Liang, Y F, Liang, S J, Lin, B, Liu, C, Liu, D, Liu, H, Liu, H D, Liu, J, Liu, J L, Liu, J S, Liu, J Y, Liu, M Y, Liu, R Y, Liu, S M, Liu, W, Liu, Y N, Liu, Z X, Liu, W J, Long, R, Lu, H K, Lv, B Q, Ma, L L, Ma, X H, Ma, J R, Mao, A, Masood, W, Mitthumsiri, T, Montaruli, Y C, Nan, B Y, Pang, P, Pattarakijwanich, Z Y, Pei, M Y, Qi, D, Ruffolo, V, Rulev, A, Sáiz, L, Shao, O, Shchegolev, X D, Sheng, J R, Shi, H C, Song, Yu V, Stenkin, V, Stepanov, Q N, Sun, X N, Sun, Z B, Sun, P H T, Tam, Z B, Tang, W W, Tian, B D, Wang, C, Wang, H, Wang, H G, Wang, J C, Wang, J S, Wang, L P, Wang, L Y, Wang, R N, Wang, W, Wang, X G, Wang, X J, Wang, X Y, Wang, Y D, Wang, Y J, Wang, Y P, Wang, Z, Wang, Z H, Wang, Z X, Wang, D M, Wei, J J, Wei, Y J, Wei, T, Wen, C Y, Wu, H R, Wu, S, Wu, W X, Wu, X F, Wu, S Q, Xi, J, Xia, J J, Xia, G M, Xiang, G, Xiao, H B, Xiao, G G, Xin, Y L, Xin, Y, Xing, D L, Xu, R X, Xu, L, Xue, D H, Yan, C W, Yang, F F, Yang, J Y, Yang, L L, Yang, M J, Yang, R Z, Yang, S B, Yang, Y H, Yao, Z G, Yao, Y M, Ye, L Q, Yin, N, Yin, X H, You, Z Y, You, Y H, Yu, Q, Yuan, H D, Zeng, T X, Zeng, W, Zeng, Z K, Zeng, M, Zha, X X, Zhai, B B, Zhang, H M, Zhang, H Y, Zhang, J L, Zhang, J W, Zhang, L, Zhang, L X, Zhang, P F, Zhang, P P, Zhang, R, Zhang, S R, Zhang, S S, Zhang, X, Zhang, X P, Zhang, Y, Zhang, Y F, Zhang, Y L, Zhang, B, Zhao, J, Zhao, L, Zhao, L Z, Zhao, S P, Zhao, F, Zheng, Y, Zheng, B, Zhou, H, Zhou, J N, Zhou, P, Zhou, R, Zhou, X X, Zhou, C G, Zhu, F R, Zhu, H, Zhu, K J, Zhu, X, Zuo, and X Y, Huang

Abstract

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Published
2021

13. Discovery of the Ultra-high energy gamma-ray source LHAASO J2108+5157

Author

Zhen Cao, F. Aharonian, Q. An, null Axikegu, L. X. Bai, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, H. Cai, J. T. Cai, Zhe Cao, J. Chang, J. F. Chang, B. M. Chen, E. S. Chen, J. Chen, Liang Chen, Long Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, X. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, S. W. Cui, X. H. Cui, Y. D. Cui, B. D’Ettorre Piazzoli, B. Z. Dai, H. L. Dai, Z. G. Dai, Dan-Zeng Dan-Zeng-Luo-Bu, D. della Volpe, X. J. Dong, K. K. Duan, J. H. Fan, Y. Z. Fan, Z. X. Fan, J. Fang, K. Fang, C. F. Feng, L. Feng, S. H. Feng, Y. L. Feng, B. Gao, C. D. Gao, L. Q. Gao, Q. Gao, W. Gao, M. M. Ge, L. S. Geng, G. H. Gong, Q. B. Gou, M. H. Gu, F. L. Guo, J. G. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, H. H. He, H. N. He, J. C. He, S. L. He, X. B. He, Y. He, M. Heller, Y. K. Hor, C. Hou, H. B. Hu, S. Hu, S. C. Hu, X. J. Hu, D. H. Huang, Q. L. Huang, W. H. Huang, X. T. Huang, X. Y. Huang, Z. C. Huang, F. Ji, X. L. Ji, H. Y. Jia, K. Jiang, Z. J. Jiang, C. Jin, T. Ke, D. Kuleshov, K. Levochkin, B. B. Li, Cheng Li, Cong Li, F. Li, H. B. Li, H. C. Li, H. Y. Li, J. Li, K. Li, W. L. Li, X. R. Li, Xin Li, Y. Li, Y. Z. Li, Zhe Li, Zhuo Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, J. S. Liu, J. Y. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. Liu, Y. N. Liu, Z. X. Liu, W. J. Long, R. Lu, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, A. Masood, Z. Min, W. Mitthumsiri, T. Montaruli, Y. C. Nan, B. Y. Pang, P. Pattarakijwanich, Z. Y. Pei, M. Y. Qi, Y. Q. Qi, B. Q. Qiao, J. J. Qin, D. Ruffolo, V. Rulev, A. Sáiz, L. Shao, O. Shchegolev, X. D. Sheng, J. Y. Shi, H. C. Song, Yu. V. Stenkin, V. Stepanov, Y. Su, Q. N. Sun, X. N. Sun, Z. B. Sun, P. H. T. Tam, Z. B. Tang, W. W. Tian, B. D. Wang, C. Wang, H. Wang, H. G. Wang, J. C. Wang, J. S. Wang, L. P. Wang, L. Y. Wang, R. N. Wang, W. Wang, X. G. Wang, X. J. Wang, X. Y. Wang, Y. Wang, Y. D. Wang, Y. J. Wang, Y. P. Wang, Z. H. Wang, Z. X. Wang, Zhen Wang, Zheng Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, S. Wu, W. X. Wu, X. F. Wu, S. Q. Xi, J. Xia, J. J. Xia, G. M. Xiang, D. X. Xiao, G. Xiao, H. B. Xiao, G. G. Xin, Y. L. Xin, Y. Xing, D. L. Xu, R. X. Xu, L. Xue, D. H. Yan, J. Z. Yan, C. W. Yang, F. F. Yang, J. Y. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, S. B. Yang, Y. H. Yao, Z. G. Yao, Y. M. Ye, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. D. Zeng, T. X. Zeng, W. Zeng, Z. K. Zeng, M. Zha, X. X. Zhai, B. B. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, J. W. Zhang, L. X. Zhang, Li Zhang, Lu Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. F. Zhang, Y. L. Zhang, Yi Zhang, Yong Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J. N. Zhou, P. Zhou, R. Zhou, X. X. Zhou, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, and X. Zuo

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Molecular cloud, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Gamma ray, Flux, Sigma, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Gamma-ray astronomy, Space and Planetary Science, Energy spectrum, Ultrahigh energy, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the discovery of a UHE gamma-ray source, LHAASO J2108+5157, by analyzing the LHAASO-KM2A data of 308.33 live days. Significant excess of gamma-ray induced showers is observed in both energy bands of 25-100 TeV and $\gt$100 TeV with 9.5 sigma and 8.5 sigma, respectively. This source is not significantly favored as an extensive source with the angular extension smaller than the point-spread function of KM2A. The measured energy spectrum from 20 to 200 TeV can be approximately described by a power-law function with an index of -2.83$\pm$ 0.18stat. A harder spectrum is demanded at lower energies considering the flux upper limit set by Fermi-LAT observations. The position of the gamma-ray emission is correlated with a giant molecular cloud, which favors a hadronic origin. No obvious counterparts have been found, deeper multiwavelength observations will help to shed new light on this intriguing UHE source., Comment: 12 pages, 7 figures, accepted by ApJL

Published
2021
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14. Geometrical reconstruction of fluorescence events observed by the LHAASO experiment *

Author

F. Aharonian, Q. An, null Axikegu, L. X. Bai, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, H. Cai, J. T. Cai, Z. Cao, J. Chang, J. F. Chang, X. C. Chang, B. M. Chen, J. Chen, L. Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, X. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, null Danzengluobu, D. della Volpe, B. D'Ettorre Piazzoli, X. J. Dong, J. H. Fan, Y. Z. Fan, Z. X. Fan, J. Fang, K. Fang, C. F. Feng, L. Feng, S. H. Feng, Y. L. Feng, B. Gao, C. D. Gao, Q. Gao, W. Gao, M. M. Ge, L. S. Geng, G. H. Gong, Q. B. Gou, M. H. Gu, J. G. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, H. H. He, H. N. He, J. C. He, S. L. He, X. B. He, Y. He, M. Heller, Y. K. Hor, C. Hou, X. Hou, H. B. Hu, S. Hu, S. C. Hu, X. J. Hu, D. H. Huang, Q. L. Huang, W. H. Huang, X. T. Huang, Z. C. Huang, F. Ji, X. L. Ji, H. Y. Jia, K. Jiang, Z. J. Jiang, C. Jin, D. Kuleshov, K. Levochkin, B. B. Li, C. Li, F. Li, H. B. Li, H. C. Li, H. Y. Li, J. Li, K. Li, W. L. Li, X. Li, X. R. Li, Y. Li, Y. Z. Li, Z. Li, E. W. Liang, Y. F. Liang, S.J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, J. S. Liu, J. Y. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. N. Liu, Z. X. Liu, W. J. Long, R. Lu, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, A. Masood, W. Mitthumsiri, T. Montaruli, Y. C. Nan, B. Y. Pang, P. Pattarakijwanich, Z. Y. Pei, M. Y. Qi, D. Ruffolo, V. Rulev, A. Sáiz, L. Shao, O. Shchegolev, X. D. Sheng, J. R. Shi, H. C. Song, Yu.V. Stenkin, V. Stepanov, Q. N. Sun, X. N. Sun, Z. B. Sun, P. H. T. Tam, Z. B. Tang, W. W. Tian, B. D. Wang, C. Wang, H. Wang, H. G. Wang, J. C. Wang, J. S. Wang, L. P. Wang, L. Y. Wang, R. N. Wang, W. Wang, X. G. Wang, X. J. Wang, X. Y. Wang, Y. D. Wang, Y. J. Wang, Y. P. Wang, Z. Wang, Z. H. Wang, Z. X. Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, S. Wu, W. X. Wu, X. F. Wu, S. Q. Xi, J. Xia, J. J. Xia, G. M. Xiang, G. Xiao, H. B. Xiao, G. G. Xin, Y. L. Xin, Y. Xing, D. L. Xu, R. X. Xu, L. Xue, D. H. Yan, C. W. Yang, F. F. Yang, J. Y. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, S. B. Yang, Y. H. Yao, Z. G. Yao, Y. M. Ye, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. D. Zeng, T. X. Zeng, W. Zeng, Z. K. Zeng, M. Zha, X. X. Zhai, B. B. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, J. W. Zhang, L. Zhang, L. X. Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. Zhang, Y. F. Zhang, Y. L. Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J. N. Zhou, P. Zhou, R. Zhou, X. X. Zhou, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, and X. Zuo

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Detector, Resolution (electron density), Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Cosmic ray, 01 natural sciences, Fluorescence, law.invention, Telescope, Optics, law, 0103 physical sciences, Trajectory, Range (statistics), 010306 general physics, business, Instrumentation, Cherenkov radiation
Abstract

The LHAASO-WFCTA experiment, which aims to observe cosmic rays in the sub-EeV range using the fluorescence technique, uses a new generation of high-performance telescopes. To ensure that the experiment has excellent detection capability associated with the measurement of the energy spectrum, the primary composition of cosmic rays, and so on, an accurate geometrical reconstruction of air-shower events is fundamental. This paper describes the development and testing of geometrical reconstruction for stereo viewed events using the WFCTA (Wide Field of view Cherenkov/Fluorescence Telescope Array) detectors. Two approaches, which take full advantage of the WFCTA detectors, are investigated. One is the stereo-angular method, which uses the pointing of triggered SiPMs in the shower trajectory, and the other is the stereo-timing method, which uses the triggering time of the fired SiPMs. The results show that both methods have good geometrical resolution; the resolution of the stereo-timing method is slightly better than the stereo-angular method because the resolution of the latter is slightly limited by the shower track length.

Published
2021
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15. Observation of the Crab Nebula with LHAASO-KM2A − a performance study *

Author

F. Aharonian, Q. An, 克古 Axikegu, L. X. Bai, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, H. Cai, J. T. Cai, Z. Cao, J. Chang, J. F. Chang, X. C. Chang, B. M. Chen, J. Chen, L. Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. H. Chen, S. Z. Chen, T. L. Chen, X. L. Chen, Y. Chen, N. Cheng, Y. D. Cheng, S. W. Cui, X. H. Cui, Y. D. Cui, B. Z. Dai, H. L. Dai, Z. G. Dai, 罗布 Danzengluobu, D. della Volpe, B. D'Ettorre Piazzoli, X. J. Dong, J. H. Fan, Y. Z. Fan, Z. X. Fan, J. Fang, K. Fang, C. F. Feng, L. Feng, S. H. Feng, Y. L. Feng, B. Gao, C. D. Gao, Q. Gao, W. Gao, M. M. Ge, L. S. Geng, G. H. Gong, Q. B. Gou, M. H. Gu, J. G. Guo, X. L. Guo, Y. Q. Guo, Y. Y. Guo, Y. A. Han, H. H. He, H. N. He, J. C. He, S. L. He, X. B. He, Y. He, M. Heller, Y. K. Hor, C. Hou, X. Hou, H. B. Hu, S. Hu, S. C. Hu, X. J. Hu, D. H. Huang, Q. L. Huang, W. H. Huang, X. T. Huang, Z. C. Huang, F. Ji, X. L. Ji, H. Y. Jia, K. Jiang, Z. J. Jiang, C. Jin, D. Kuleshov, K. Levochkin, B. B. Li, C. Li, F. Li, H. B. Li, H. C. Li, H. Y. Li, J. Li, K. Li, W. L. Li, X. Li, X. R. Li, Y. Li, Y. Z. Li, Z. Li, E. W. Liang, Y. F. Liang, S. J. Lin, B. Liu, C. Liu, D. Liu, H. Liu, H. D. Liu, J. Liu, J. L. Liu, J. S. Liu, J. Y. Liu, M. Y. Liu, R. Y. Liu, S. M. Liu, W. Liu, Y. N. Liu, Z. X. Liu, W. J. Long, R. Lu, H. K. Lv, B. Q. Ma, L. L. Ma, X. H. Ma, J. R. Mao, A. Masood, W. Mitthumsiri, T. Montaruli, Y. C. Nan, B. Y. Pang, P. Pattarakijwanich, Z. Y. Pei, M. Y. Qi, D. Ruffolo, V. Rulev, A. Sáiz, L. Shao, O. Shchegolev, X. D. Sheng, J. R. Shi, H. C. Song, Yu. V. Stenkin, V. Stepanov, Q. N. Sun, X. N. Sun, Z. B. Sun, P. H. T. Tam, Z. B. Tang, W. W. Tian, B. D. Wang, C. Wang, H. Wang, H. G. Wang, J. C. Wang, J. S. Wang, L. P. Wang, L. Y. Wang, R. N. Wang, W. Wang, X. G. Wang, X. J. Wang, X. Y. Wang, Y. D. Wang, Y. J. Wang, Y. P. Wang, Z. Wang, Z. H. Wang, Z. X. Wang, D. M. Wei, J. J. Wei, Y. J. Wei, T. Wen, C. Y. Wu, H. R. Wu, S. Wu, W. X. Wu, X. F. Wu, S. Q. Xi, J. Xia, J. J. Xia, G. M. Xiang, G. Xiao, H. B. Xiao, G. G. Xin, Y. L. Xin, Y. Xing, D. L. Xu, R. X. Xu, L. Xue, D. H. Yan, C. W. Yang, F. F. Yang, J. Y. Yang, L. L. Yang, M. J. Yang, R. Z. Yang, S. B. Yang, Y. H. Yao, Z. G. Yao, Y. M. Ye, L. Q. Yin, N. Yin, X. H. You, Z. Y. You, Y. H. Yu, Q. Yuan, H. D. Zeng, T. X. Zeng, W. Zeng, Z. K. Zeng, M. Zha, X. X. Zhai, B. B. Zhang, H. M. Zhang, H. Y. Zhang, J. L. Zhang, J. W. Zhang, L. Zhang, L. X. Zhang, P. F. Zhang, P. P. Zhang, R. Zhang, S. R. Zhang, S. S. Zhang, X. Zhang, X. P. Zhang, Y. Zhang, Y. F. Zhang, Y. L. Zhang, B. Zhao, J. Zhao, L. Zhao, L. Z. Zhao, S. P. Zhao, F. Zheng, Y. Zheng, B. Zhou, H. Zhou, J. N. Zhou, P. Zhou, R. Zhou, X. X. Zhou, C. G. Zhu, F. R. Zhu, H. Zhu, K. J. Zhu, and X. Zuo

Subjects
Physics, Nuclear and High Energy Physics, High energy, 010308 nuclear & particles physics, Cosmic distance ladder, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Crab Nebula, 0103 physical sciences, Energy spectrum, 010306 general physics, Instrumentation, Energy (signal processing)
Abstract

A sub-array of the Large High Altitude Air Shower Observatory (LHAASO), KM2A is mainly designed to observe a large fraction of the northern sky to hunt for γ-ray sources at energies above 10 TeV. Even though the detector construction is still underway, half of the KM2A array has been operating stably since the end of 2019. In this paper, we present the KM2A data analysis pipeline and the first observation of the Crab Nebula, a standard candle in very high energy γ-ray astronomy. We detect γ-ray signals from the Crab Nebula in both energy ranges of 10 100 TeV and 100 TeV with high significance, by analyzing the KM2A data of 136 live days between December 2019 and May 2020. With the observations, we test the detector performance, including angular resolution, pointing accuracy and cosmic-ray background rejection power. The energy spectrum of the Crab Nebula in the energy range 10-250 TeV fits well with a single power-law function dN/dE = (1.13 0.05 0.08 ) 10 (E/20 TeV) cm s TeV . It is consistent with previous measurements by other experiments. This opens a new window of γ-ray astronomy above 0.1 PeV through which new ultrahigh-energy γ-ray phenomena, such as cosmic PeVatrons, might be discovered.

Published
2021
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16. An Improved Projection Method for Determination of Fatigue Parameters of Metal Structures Based on Spherical Direction Cosine Group Construction

Author

Yang Baozhu, B. Chen, B. Q. Ma, Shi-De Xiao, Y. Y. Wu, Guangwu Yang, and Zhu Tao

Subjects
Engineering, business.industry, Научно-технический раздел, 020101 civil engineering, Improved method, 02 engineering and technology, Structural engineering, Welding, Fatigue limit, Bogie, Direction cosine, 0201 civil engineering, law.invention, Stress (mechanics), 020303 mechanical engineering & transports, 0203 mechanical engineering, Mechanics of Materials, law, Solid mechanics, Projection method, business
Abstract

The key components of railway rolling stock are almost constantly in the multiaxial stress state in service. To evaluate the fatigue strength of the structure, stress parameters should be obtained beforehand. The traditional projection method assumes that the maximum principal stress is the maximum tensile stress, and then the projection process is performed without taking the tension/ compression states of principal stresses into account. To address these inadequacies, a method for fatigue parameter determination was proposed based on principal stress projection toward a spherical direction cosine group. This method can determine the direction of maximum tensile stress and preserve the tension/compression attribute of stress during calculating the maximum stress and the minimum stress. Therefore, the physical meaning of present improved method is more apparent than the traditional projection method, and its algorithm is simple and effective. The fatigue strength assessments of a welded bogie frame were performed utilizing the traditional projection method and present method respectively. Results show that some maximum stresses calculated by the improved method could be 19.4% higher than those obtained by the traditional one at some nodes, while the minimum stresses and the stress ratio deduced from these two methods could even be of opposite sign. The present method, which takes the tension/compression properties of principal stresses into consideration, is more reasonable, as compared with the traditional projection method, and thus the fatigue strength assessment results are more credible.

Published
2016
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17. A Probabilistic Model for Describing Short Fatigue Crack Growth Behavior of LZ50 Steel

Author

Yang Baozhu, Yong Xiang Zhao, B. Q. Ma, and Shi-De Xiao

Subjects
Correlation coefficient, Estimation theory, 05 social sciences, Statistical model, 02 engineering and technology, Paris' law, Standard deviation, 020303 mechanical engineering & transports, 0203 mechanical engineering, Mechanics of Materials, 0502 economics and business, Solid mechanics, Applied mathematics, Growth rate, 050203 business & management, Test data, Mathematics
Abstract

Fatigue damage process of metal components and structures with smooth surface belongs primarily to the short fatigue crack stage. To characterize the random growth behavior of short fatigue crack and to apply the crack growth rate model for engineering safety assessment, a probabilistic model is proposed with consideration of the test data scattering regularity. This probabilistic model is based on the multi-microstructural barriers’ model and can describe the deceleration behavior of crack growth rate during the total short fatigue crack propagation period. To take the statistical characteristics of the test data into account, the idea from the general maximum likelihood method which is widely used in parameter estimation of fatigue S – N curves and e – N curves is inherited. While estimating the parameters of the probabilistic model, the conventional correlation coefficient optimization method is extended for calculating the parameters of both the mean and the standard deviation curves. Analysis of the test data of LZ50 steel indicates the reasonability and applicability of the proposed model.

Published
2016
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19. Erratum to: Spin density matrix elements in exclusive $$\omega $$ electroproduction on $$^1$$H and $$^2$$H targets at 27.5 GeV beam energy

Author

P. E. Reimer, V. A. Kozlov, P. F. Dalpiaz, T. A. Shibata, B. Marianski, V. Bryzgalov, E. De Sanctis, V. Gharibyan, D. Hasch, G. Schnell, Morgan Murray, L. Felawka, F. Garibaldi, C. Riedl, W.-D. Nowak, G. Ciullo, L. Lagamba, G. P. Capitani, S. Joosten, A. Kisselev, C. Van Hulse, Wouter Deconinck, Luciano Pappalardo, Y. Van Haarlem, H. P. Blok, Z. Akopov, Michael Tytgat, E. Cisbani, Wolfgang Lorenzon, E. Etzelmüller, D. Zeiler, Frank Ellinghaus, Ivana Hristova, J. J. M. Steijger, Riccardo Fabbri, S. Yaschenko, Michael Düren, M. Ehrenfried, S. Taroian, B. Zihlmann, Y. J. Mao, P. Zupranski, M. Statera, A. R. Reolon, E. R. Kinney, Y. Naryshkin, V. A. Korotkov, Alexander Borissov, M. Capiluppi, B. Seitz, M. Diefenthaler, A. Movsisyan, H. Marukyan, A. Nass, I. Vilardi, R. Perez-Benito, G. Elbakian, B. Q. Ma, S. I. Manaenkov, Adel Terkulov, P. Di Nezza, R. Truty, M. Contalbrigo, R. De Leo, A. Airapetian, D. Gabbert, P. Kravchenko, Klaus Rith, A. Petrosyan, M. Hartig, S. Frullani, Dirk Ryckbosch, H. E. Jackson, V. G. Krivokhijine, S. Yen, A. Ivanilov, Ralf Kaiser, M. Stahl, L. Lapikás, E. Steffens, G. Gavrilov, David Mahon, Andreas Schäfer, I. Lehmann, V. A. Gapienko, T. Keri, V. Vikhrov, K. P. Schüler, Y. Holler, N. Akopov, G. Karyan, Shan Wang, A. Rostomyan, A. Avetissian, G. Gapienko, P. Lenisa, A. Trzcinski, W. Augustyniak, and M. Stancari

Subjects
Physics, Nuclear physics, Matrix (mathematics), Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, 0103 physical sciences, Atomic physics, Spin density, 010306 general physics, 01 natural sciences, Engineering (miscellaneous), Omega, Beam energy
Published
2016
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20. Transverse momentum broadening of hadrons produced in semi-inclusive deep-inelastic scattering on nuclei

Author

V. A. Korotkov, Wouter Deconinck, T. Keri, G. Elbakian, W.-D. Nowak, M. Hartig, S. Frullani, P. Di Nezza, D. Veretennikov, S. I. Manaenkov, Alessandra Fantoni, V. A. Gapienko, Cynthia Marie Hadjidakis, M. Hoek, Y. Miyachi, L. Manfré, A. Martinez de la Ossa, A. López Ruiz, P. E. Reimer, T. A. Shibata, G. Hill, A. Nass, F. Sanftl, V. Vikhrov, D. Hasch, M. Statera, Y. Van Haarlem, S. Belostotski, M. Capiluppi, V. Bryzgalov, D. Zeiler, C. Vogel, Xianguo Lu, M. Negodaev, W. Augustyniak, Ferdinando Giordano, M. Diefenthaler, H. Marukyan, H. S. Jo, B. Seitz, E. Nappi, Vitaly Shutov, H. P. Blok, A. Hillenbrand, Y. Imazu, J. Burns, David Mahon, Stephen V. Gliske, P. B. van der Nat, Morgan Murray, Wolfgang Lorenzon, Andreas Schäfer, L. Felawka, Frank Ellinghaus, Y. Salomatin, N. Akopov, E. R. Kinney, B. Marianski, E. De Sanctis, Ivana Hristova, L. Lagamba, Y. Naryshkin, J. J. M. Steijger, Michael Düren, M. Stancari, S. Yaschenko, C. Bonomo, E. Cisbani, H. E. Jackson, G. P. Capitani, R. Perez-Benito, B. Q. Ma, F. Garibaldi, P. F. Dalpiaz, R. Lamb, B. Ball, K. Rith, Z. Akopov, R. De Leo, Shan Wang, W. Yu, P. Lenisa, L. De Nardo, A. Trzcinski, Zhenyu Ye, J. Dreschler, I. Vilardi, H. Böttcher, V. Gharibyan, C. Riedl, Andreas Mussgiller, A. Rostomyan, A. R. Reolon, A. Avetissian, G. Ciullo, Arne Vandenbroucke, Riccardo Fabbri, E. Avetisyan, S. Joosten, A. Kisselev, V. Kozlov, A. Jgoun, J. G. Rubin, I. Lehmann, K. P. Schüler, Nicola Bianchi, P. Zupranski, L. A. Linden-Levy, J. Stewart, G. Rosner, A. Airapetian, F. Stinzing, G. Schnell, L. Lapikás, Valeria Muccifora, M. Contalbrigo, Hengqiang Ye, B. Zihlmann, L. L. Pappalardo, Martin Raithel, Alexander Borissov, Hasko Stenzel, Michael Tytgat, E. C. Aschenauer, S. Taroian, C. A. Miller, D. Gabbert, Ralf Kaiser, M. Ehrenfried, E. Steffens, N. C. R. Makins, N. Pickert, Dirk Ryckbosch, A. Movsisyan, Y. Holler, G. Karyan, Y. J. Mao, P. Kravchenko, X. R. Lu, C. B. Van Hulse, and A. Ivanilov

Subjects
HERMES experiment, Nuclear and High Energy Physics, Particle physics, Meson, DEUTERIUM, Hadron, FOS: Physical sciences, Virtual particle, 7. Clean energy, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), TARGETS, 0103 physical sciences, ddc:530, HADRONIZATION, Nuclear Experiment, 010306 general physics, Mass number, Physics, 010308 nuclear & particles physics, HERA, Deep inelastic scattering, Physics and Astronomy, High Energy Physics::Experiment, FRAGMENTATION, Lepton
Abstract

The first direct measurement of the dependence on target nuclear mass of the average squared transverse momentum of pi+, pi-, and K+ mesons from deep-inelastic lepton scattering is obtained as a function of several kinematic variables. The data were accumulated at the HERMES experiment at DESY, in which the HERA 27.6 GeV lepton beam was scattered off several nuclear gas targets. The average squared transverse momentum was clearly observed to increase with atomic mass number. The effect increases as a function of Q**2 and x and remains constant as a function of both the virtual photon energy nu and the fractional hadron energy z, except that it vanishes as z approaches unity., Comment: 6 pages, 2 figures

Published
2010
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21. Single-spin azimuthal asymmetry in exclusive electroproduction of π+ mesons on transversely polarized protons

Author

P. Lenisa, A. Trzcinski, S. Belostotski, Xianguo Lu, V. Bryzgalov, Wouter Deconinck, Adel Terkulov, J. J. M. Steijger, W. Augustyniak, I. Vilardi, Y. Holler, V. A. Korotkov, M. Varanda, R. Perez-Benito, M. Contalbrigo, David Mahon, Morgan Murray, J. Stewart, C. Riedl, Andreas Schäfer, Michael Tytgat, T. A. Shibata, B. Zihlmann, L. L. Pappalardo, C. B. Van Hulse, S. Taroian, D. Veretennikov, Hengqiang Ye, V. A. Gapienko, A. Ivanilov, C. Bonomo, E. Cisbani, Alexander Borissov, Hasko Stenzel, A. Airapetian, B. Seitz, E. C. Aschenauer, N. Akopov, F. Giordano, T. Keri, Vitaly Shutov, H. P. Blok, Naomi C R Makins, Y. J. Mao, P. Kravchenko, G. Elbakian, Y. Naryshkin, Wolfgang Lorenzon, M. Capiluppi, Valeria Muccifora, E. Avetisyan, S. I. Manaenkov, Dirk Ryckbosch, J. Burns, G. Ciullo, Ivana Hristova, S. Yaschenko, Frank Ellinghaus, Stephen V. Gliske, E. R. Kinney, V. Vikhrov, A. Hillenbrand, Y. Imazu, L. Felawka, P. B. van der Nat, A. Movsisyan, F. Sanftl, P. Zupranski, S. Yen, K. Rith, W.-D. Nowak, G. P. Capitani, Ralf Kaiser, M. Ehrenfried, M. Statera, J. Dreschler, D. Zeiler, L. Manfré, G. Rosner, R. Lamb, G. Hill, C. Vogel, E. De Sanctis, L. Lagamba, Eugenio Nappi, Z. Akopov, Nagao Kobayashi, F. Garibaldi, C. A. Miller, X. R. Lu, W. Yu, D. Gabbert, M. Diefenthaler, H. Marukyan, P. E. Reimer, Alessandra Fantoni, M. Hoek, H. S. Jo, A. Nass, H. E. Jackson, Shan Wang, Y. Salomatin, A. Rostomyan, A. R. Reolon, B. Q. Ma, A. Avetissian, B. Ball, R. De Leo, H. Böttcher, Andreas Mussgiller, A. López Ruiz, Y. Van Haarlem, B. Martinez de la Ossa, Michael Düren, M. Stancari, M. Hartig, S. Frullani, P. Di Nezza, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, K. P. Schüler, L. De Nardo, Zhenyu Ye, Nicola Bianchi, V. Gharibyan, J. G. Rubin, I. Lehmann, B. Marianski, P. F. Dalpiaz, Arne Vandenbroucke, Riccardo Fabbri, S. Joosten, A. Kisselev, L. A. Linden-Levy, G. Schnell, and L. Lapikás

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Proton, Meson, 010308 nuclear & particles physics, Scattering, media_common.quotation_subject, Virtual particle, 01 natural sciences, Asymmetry, Nuclear physics, 0103 physical sciences, Photon polarization, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, media_common
Abstract

Exclusive electroproduction of π+ mesons was studied by scattering 27.6 GeV positrons or electrons off a transversely polarized hydrogen target. The single-spin azimuthal asymmetry with respect to target polarization was measured as a function of the Mandelstam variable t, the Bjorken scaling variable xB, and the virtuality Q2 of the exchanged photon. The extracted Fourier components of the asymmetry were found to be consistent with zero, except one that was found to be large and that involves interference of contributions from longitudinal and transverse virtual photons.

Published
2010
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22. Exclusive ρ0 electroproduction on transversely polarized protons

Author

P. Zupranski, C. A. Miller, P. Lenisa, A. Fantoni, T. A. Shibata, B. Zihlmann, L. L. Pappalardo, G. Rosner, D. Gabbert, Hengqiang Ye, A. Trzcinski, A. López Ruiz, Alexander Borissov, Hasko Stenzel, Xianguo Lu, T. Keri, G. Ciullo, W.-D. Nowak, S. Yen, M. Contalbrigo, M. Diefenthaler, E. C. Aschenauer, Ralf Kaiser, V. Muccifora, Naomi C R Makins, H. Marukyan, E. Steffens, Y. Van Haarlem, E. Avetisyan, Michael Tytgat, A. R. Reolon, A. Martinez de la Ossa, E. Cisbani, X. R. Lu, M. Ehrenfried, A. Hillenbrand, Y. Imazu, A. Airapetian, Stephen V. Gliske, F. Sanftl, S. Yaschenko, V. Vikhrov, M. Statera, C. Hadjidakis, L. Lagamba, S. Taroian, N. Akopov, Y. Salomatin, P. Di Nezza, B. Q. Ma, W. Augustyniak, D. Zeiler, M. Varanda, F. Stinzing, V. Bryzgalov, C. Vogel, Y. J. Mao, P. Kravchenko, B. Ball, Morgan Murray, L. Manfré, A. Movsisyan, M. Hartig, R. Lamb, R. De Leo, V. A. Korotkov, F. Giordano, David Mahon, J. Stewart, M. Hoek, C. B. Van Hulse, Adel Terkulov, L. Fellawka, Frank Ellinghaus, Andreas Schäfer, E. R. Kinney, R. Perez-Benito, A. Ivanilov, C. Bonomo, J. Burns, M. Capiluppi, H. Böttcher, H. E. Jackson, Y. Naryshkin, G. Elbakian, W. Yu, S. I. Manaenkov, A. Nass, J. G. Rubin, V. A. Gapienko, N. Bianchi, Andreas Mussgiller, Wouter Deconinck, G. Hill, Y. Holler, B. Seitz, I. Lehmann, K. Rith, E. Nappi, Z. Akopov, Nagao Kobayashi, P. B. van der Nat, J. Dreschler, P. E. Reimer, Shan Wang, D. Veretennikov, L. A. Linden-Levy, G. Schnell, C. Riedl, L. Lapikás, K. P. Schüler, Vitaly Shutov, P.F. Dalpiaz, A. Rostomyan, H. P. Blok, A. Avetissian, G.P. Capitani, H. S. Jo, Wolfgang Lorenzon, G. Gapienko, Ivana Hristova, E. De Sanctis, D. Hasch, S. Frullani, Dirk Ryckbosch, B. Marianski, Arne Vandenbroucke, Riccardo Fabbri, S. Joosten, A. Kisselev, J. J. M. Steijger, Michael Düren, M. Stancari, L. De Nardo, Zhenyu Ye, I. Vilardi, V. Gharibyan, Y. Miyachi, and (Astro)-Particles Physics

Subjects
14.40.Aq, Quark, Nuclear and High Energy Physics, Particle physics, Meson, FOS: Physical sciences, HERMES, Parton, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Matrix (mathematics), 13.88.+e, GENERALIZED PARTON DISTRIBUTIONS, Total angular momentum quantum number, 0103 physical sciences, Proton spin crisis, ddc:530, NUCLEON, Nuclear Experiment, 010306 general physics, VIRTUAL COMPTON-SCATTERING, Physics, 010308 nuclear & particles physics, 13.60.Le, 14.20.Dh, 12.38.Qk, QCD, Helicity, TARGET, Physics and Astronomy, High Energy Physics::Experiment, SDG 6 - Clean Water and Sanitation, Nucleon, VECTOR-MESON PRODUCTION
Abstract

The exclusive electroproduction of rho-0 mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. Spin density matrix elements for this process were determined from the measured production- and decay-angle distributions of the produced rho-0 mesons. These matrix elements embody information on helicity transfer and the validity of s-channel helicity conservation in the case of a transversely polarized target. From the spin density matrix elements, the leading-twist term in the single-spin asymmetry was calculated separately for longitudinally and transversely polarized rho-0 mesons. Neglecting s-channel helicity changing matrix elements, results for the former can be compared to calculations based on generalized parton distributions, which are sensitive to the contribution of the total angular momentum of the quarks to the proton spin., 7 pages, 5 figures

Published
2009
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23. Measurement of parton distributions of strange quarks in the nucleon from charged-kaon production in deep-inelastic scattering on the deuteron

Author

A. Reischl, W. Augustyniak, R. Perez-Benito, B. Maiheu, Alessandra Fantoni, D. Veretennikov, M. Negodaev, B. Hommez, G. Ciullo, Tetsuya Hasegawa, M. Hoek, E. De Sanctis, V. A. Gapienko, W.H.A. Hesselink, B. Zihlmann, Y. Naryshkin, P. E. Reimer, A. Kisselev, J. G. Rubin, A. Brull, B. Tchuiko, M. Kopytin, Cynthia Marie Hadjidakis, Y. Miyachi, A. Nass, G. Gapienko, I. Lehmann, D. Hasch, A. López Ruiz, Z. Akopov, A. Elalaoui-Moulay, Frank Ellinghaus, C. Shearer, B. Seitz, A. Hillenbrand, Y. Imazu, E. Nappi, Y. Van Haarlem, Michael Tytgat, E. R. Kinney, Y. Holler, A. Airapetian, U. Elschenbroich, S. Taroian, P. Lenisa, David Mahon, Y. Salomatin, B. Marianski, A. Trzcinski, P. B. van der Nat, J. Burns, Shan Wang, F. Stinzing, Andreas Schäfer, H. E. Jackson, V. G. Krivokhijine, A. Funel, B. Q. Ma, J. J. M. Steijger, Michael Düren, G. van der Steenhoven, A. Osborne, M. Stancari, P. Zupranski, C. Riedl, S. E. Rock, P. Di Nezza, V. Vikhrov, L. Rubacek, R. De Leo, A. Rostomyan, K. Rith, C. B. Van Hulse, A. Borissov, A. R. Reolon, A. Avetissian, M. Capiluppi, P. Liebing, A. Ivanilov, S. Belostotski, G. Rosner, H. Böttcher, V. Bryzgalov, J. Dreschler, L. De Nardo, W. Yu, F. Garibaldi, Morgan Murray, G. Iarygin, Zhenyu Ye, E. C. Aschenauer, G. Hill, K. P. Schüler, Y. X. Ye, P.F. Dalpiaz, J. Stewart, I. Vilardi, Andreas Mussgiller, A. Andrus, M. Diefenthaler, V. Gharibyan, P. Tait, L. A. Linden-Levy, W.-D. Nowak, T. A. Shibata, E. Avetissian, M. Demey, Nicola Bianchi, R.O. Avakian, H. Marukyan, C. Bonomo, E. Cisbani, V. A. Kozlov, D. Reggiani, G. Schnell, F. Giordano, S. Joosten, J. Streit, I. M. Gregor, H. Ye, A. Jgoun, Arne Vandenbroucke, Riccardo Fabbri, L. Manfré, Stephen V. Gliske, H. Guler, M. Varanda, L. Felawka, X. R. Lu, L. Lagamba, S. Yen, G. P. Capitani, Ralf Kaiser, E. Steffens, G. Gavrilov, L. Lapikás, M. Contalbrigo, Martin Raithel, I. Sanjiev, Naomi C R Makins, M. Ehrenfried, Andrey V. Izotov, C. A. Miller, D. Gabbert, Tsutomu Kobayashi, M. Statera, S. Frullani, N. Pickert, Dirk Ryckbosch, D. Zeiler, C. Vogel, V. A. Korotkov, G. Elbakian, S. Lu, Y. J. Mao, P. Kravchenko, Adel Terkulov, T. Keri, L. L. Pappalardo, Hasko Stenzel, Wouter Deconinck, Valeria Muccifora, V. Mexner, A. Nagaitsev, N. Akopov, S. Yaschenko, Vitaly Shutov, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, R. Lamb, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Quark, Particle physics, Strange quark, Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, Parton, 01 natural sciences, NO, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 13.60.-r, 13.88.+e, 14.20.Dh, 14.65.-q, 0103 physical sciences, ddc:530, SDG 14 - Life Below Water, 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Scattering, Deep inelastic scattering, Helicity, Strange matter, Physics and Astronomy, High Energy Physics::Experiment, Nucleon
Abstract

The momentum and helicity density distributions of the strange quark sea in the nucleon are obtained in leading order from charged-kaon production in deep-inelastic scattering on the deuteron. The distributions are extracted from spin-averaged K+/- multiplicities, and from K+/- and inclusive double-spin asymmetries for scattering of polarized positrons by a polarized deuterium target. The shape of the momentum distribution is softer than that of the average of the ubar and dbar quarks. In the region of measurement 0.02 < x < 0.6 and Q^2 > 1.0 GeV^2, the helicity distribution is zero within experimental uncertainties., 5 pages, 5 figures, 1 table; text slightly expanded, 10 references added

Published
2008
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24. Spin density matrix elements in exclusive omega electroproduction on H-1 and H-2 targets at 27.5 GeV beam energy (vol 74, 3110, 2014)

Author

Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, M., Capitani, G. P., Cisbani, E., Ciullo, Giuseppe, Contalbrigo, M., Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmueller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikas, L., Lehmann, I., Lenisa, Paolo, Lorenzon, W., B. Q., Ma, Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schaefer, A., Schnell, G., Schueler, K. P., Seitz, B., Shibata, T. A., Stahl, M., Stancari, M., Statera, Marco, Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
PHYSICS, MINIMAL FLAVOR VIOLATION, SYMMETRY, SEARCH, STANDARD MODEL, HIGGS-BOSON, DECAYS, LHC, COUPLINGS, PARTICLE, Socio-culturale
Published
2016

25. Transverse-target-spin asymmetry in exclusive $$\omega $$-meson electroproduction

Author

G. Ciullo, A. Movsisyan, A. Ivanilov, P. E. Reimer, Y. Holler, P. Lenisa, A. Trzcinski, F. Giordano, M. Contalbrigo, M. Negodaev, I. Lehmann, Klaus Rith, V. Muccifora, P. F. Dalpiaz, E. C. Aschenauer, G. Gapienko, G. Schnell, Frank Ellinghaus, V. A. Korotkov, B. Marianski, E. R. Kinney, Adel Terkulov, V. A. Gapienko, P. Zupranski, M. Statera, Y. Naryshkin, N. Akopov, E. De Sanctis, S. Yen, V. Gharibyan, W. Augustyniak, G. Karyan, G. Elbakian, Ralf Kaiser, S. I. Manaenkov, L. Lapikás, Michael Tytgat, Shan Wang, H. E. Jackson, Wouter Deconinck, V. G. Krivokhijine, S. Taroian, Y. Van Haarlem, S. Joosten, V. Vikhrov, E. Steffens, G. Rosner, R. Truty, A. Kisselev, C. Van Hulse, J. Rubin, M. Hoek, Y. Salomatin, B. Seitz, D. Gabbert, A. Rostomyan, C. Vogel, A. Avetissian, Y. J. Mao, B. Q. Ma, W.-D. Nowak, A. R. Reolon, A. Airapetian, A. Nass, B. Zihlmann, R. De Leo, L. L. Pappalardo, M. Diefenthaler, H. Marukyan, S. Belostotski, T. A. Shibata, V. Bryzgalov, Alexander Borissov, T. Keri, R. Perez-Benito, F. Stinzing, S. Frullani, P. Di Nezza, Dirk Ryckbosch, H. P. Blok, Wolfgang Lorenzon, S. Yaschenko, J. J. M. Steijger, Michael Düren, C. Riedl, Y. Miyachi, D. Hasch, I. Vilardi, A. Petrosyan, Z. Akopov, V. A. Kozlov, Stephen V. Gliske, L. Felawka, L. Lagamba, and G. P. Capitani

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Meson, media_common.quotation_subject, Momentum transfer, DESY, Omega, Asymmetry, Nuclear physics, Pion, Positron, High Energy Physics::Experiment, Nuclear Experiment, Nucleon, Engineering (miscellaneous), media_common
Abstract

Hard exclusive electroproduction of omega mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five azimuthal modulations of the single-spin asymmetry of the cross section with respect to the transverse proton polarization are measured. They are determined in the entire kinematic region as well as for two bins in photon virtuality and momentum transfer to the nucleon. Also, a separation of asymmetry amplitudes into longitudinal and transverse components is done. These results are compared to a phenomenological model that includes the pion pole contribution. Within this model, the data favor a positive pi omega transition form factor.

Published
2015
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26. Bose–Einstein correlations in hadron-pairs from lepto-production on nuclei ranging from hydrogen to xenon

Author

E. Nappi, Zhenyu Ye, I. Vilardi, V. A. Gapienko, N. Bianchi, G. Gapienko, F. Giordano, Adel Terkulov, V. Vikhrov, P. F. Dalpiaz, B. Marianski, J. Rubin, C. Van Hulse, Stephen V. Gliske, L. Felawka, V. A. Korotkov, L. Lagamba, P. E. Reimer, G. Elbakian, Morgan Murray, E. Avetisyan, G. P. Capitani, I. Lehmann, Frank Ellinghaus, Klaus Rith, P. Lenisa, G. Schnell, E. R. Kinney, S. Joosten, Y. Holler, M. Statera, Y. Miyachi, Y. Naryshkin, A. Trzcinski, A. Kisselev, A. Nass, D. Hasch, Shan Wang, Andreas Mussgiller, Luciano Pappalardo, B. Zihlmann, V. A. Kozlov, J. Garay Garcia, Alexander Borissov, W.-D. Nowak, M. Capiluppi, A. R. Reolon, Michael Tytgat, E. Cisbani, Z. Akopov, A. Martinez de la Ossa, A. López Ruiz, M. Diefenthaler, S. Taroian, Riccardo Fabbri, H. Marukyan, Y. Van Haarlem, A. Rostomyan, A. Avetissian, G. Ciullo, J. Burns, W. Augustyniak, N. C. R. Makins, Y. Salomatin, Xianguo Lu, M. Stancari, B. Q. Ma, S. Yen, Ralf Kaiser, H. E. Jackson, V. G. Krivokhijine, S. Frullani, M. Hartig, E. De Sanctis, V. Gharibyan, A. Movsisyan, S. Belostotski, J. J. M. Steijger, M. Negodaev, E. Etzelmüller, V. Bryzgalov, Dirk Ryckbosch, R. De Leo, Michael Düren, F. Garibaldi, G. Gavrilov, M. Stahl, A. Ivanilov, A. Fantoni, M. Contalbrigo, E. C. Aschenauer, David Mahon, D. Veretennikov, Andreas Schäfer, A. Petrosyan, Y. J. Mao, T. Keri, Wouter Deconinck, L. Lapikás, N. Akopov, G. Karyan, P. Di Nezza, P. Kravchenko, S. Yaschenko, R. Perez-Benito, Vitaly Shutov, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, C. Riedl, Y. Imazu, A. Airapetian, T. A. Shibata, R.O. Avakian, P. Zupranski, G. Rosner, R. Truty, and B. Seitz

Subjects
Physics, Nuclear reaction, HERMES experiment, Physics and Astronomy (miscellaneous), Hadron, Elementary particle, Bose–Einstein correlations, Deep inelastic scattering, Charged particle, Nuclear physics, Pair production, Atomic physics, Nuclear Experiment, Engineering (miscellaneous)
Abstract

Bose–Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of $$^1$$ H, $$^2$$ H, $$^3$$ He, $$^4$$ He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation function is compared to two different empirical distributions that do not include the Bose–Einstein correlations. One distribution is derived from unlike-sign hadron pairs, and the second is derived from mixing like-sign pairs from different events. The extraction procedure used simulations incorporating the experimental setup in order to correct the results for spectrometer acceptance effects, and was tested using the distribution of unlike-sign hadron pairs. Clear signals of Bose–Einstein correlations for all target nuclei without a significant variation with the nuclear target mass are found. Also, no evidence for a dependence on the invariant mass W of the photon-nucleon system is found when the results are compared to those of previous experiments.

Published
2015
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27. PentaquarkΘ+search at HERMES

Author

A. Petrosyan, C. A. Miller, W. Augustyniak, R. Perez-Benito, D. Gabbert, B. Zihlmann, Alexander Borissov, Xianguo Lu, M. Negodaev, H. E. Jackson, V. G. Krivokhijine, T. Keri, V. Vikhrov, Shan Wang, I. Vilardi, S. Yaschenko, Y. Salomatin, G. Schnell, E. De Sanctis, Morgan Murray, G. Elbakian, Y. Holler, P. Zupranski, S. I. Manaenkov, Franco Garibaldi, J. Garay Garcia, A. Trzcinski, J. J. M. Steijger, P. Kravchenko, W.-D. Nowak, L. Lagamba, Z. Akopov, Michael Tytgat, A. Rostomyan, A. R. Reolon, A. Avetissian, Hengqiang Ye, B. Q. Ma, E. Cisbani, S. Taroian, G. Rosner, R. Truty, P. E. Reimer, C. Van Hulse, Y. Imazu, D. Hasch, R. De Leo, Salvatore Frullani, Riccardo Fabbri, K. P. Schüler, A. Martinez de la Ossa, B. Seitz, F. Giordano, P. F. Dalpiaz, M. Stancari, E. Avetisyan, J. Bowles, G. Ciullo, Adel Terkulov, Zhenyu Ye, H. P. Blok, Eugenio Nappi, T. A. Shibata, Dirk Ryckbosch, R.O. Avakian, A. Movsisyan, Alessandra Fantoni, Wolfgang Lorenzon, A. López Ruiz, A. Ivanilov, M. Hartig, P. Di Nezza, Y. Van Haarlem, S. Yen, A. Nass, Ivana Hristova, Stephen V. Gliske, J. G. Rubin, I. Lehmann, Ralf Kaiser, David Mahon, L. Felawka, B. Marianski, Y. Miyachi, G. P. Capitani, G. Gavrilov, S. Joosten, A. Kisselev, V. Kozlov, Luciano Pappalardo, M. Contalbrigo, C. Riedl, E. Etzelmüller, Klaus Rith, E. R. Kinney, S. Belostotski, V. Bryzgalov, J. Burns, H. Marukyan, N. Akopov, D. Veretennikov, L. Lapikás, G. Karyan, Wouter Deconinck, and Y. J. Mao

Subjects
RING, Nuclear and High Energy Physics, Particle physics, Baryon production, 01 natural sciences, Particle identification, NO, DECUPLET, Nuclear physics, 0103 physical sciences, Baryons, Invariant mass, Nuclear Experiment, 010306 general physics, Glueball and nonstandard multi-quark, SKYRME MODEL, BARYONS, Physics, 010308 nuclear & particles physics, Hyperon, Pentaquark, Baryon, Physics and Astronomy, Deuterium, Excited state, High Energy Physics::Experiment, Event (particle physics), Glueball and nonstandard multi-quark, Pentaquark, Baryon production, Baryons
Abstract

The earlier search at HERMES for narrow baryon states excited in quasireal photoproduction, decaying through the channel pK(S)(0) -> p pi(+)pi(-), has been extended with improved decay-particle reconstruction, more advanced particle identification, and increased event samples. The structure observed earlier at an invariant mass of 1528 MeV shifts to 1522 MeV and the statistical significance drops to about 2 sigma for data taken with a deuterium target. The number of events above background is 68(-31)(+98)(stat) +/- 13(sys). No such structure is observed in the hydrogen data set.

Published
2015
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28. Hard exclusive electroproduction of π+π− pairs

Author

A. Airapetian, N. Akopov, Z. Akopov, M. Amarian, V.V. Ammosov, A. Andrus, E.C. Aschenauer, W. Augustyniak, R. Avakian, A. Avetissian, E. Avetissian, P. Bailey, D. Balin, V. Baturin, M. Beckmann, S. Belostotski, S. Bernreuther, N. Bianchi, H.P. Blok, H. Böttcher, A. Borissov, A. Borysenko, M. Bouwhuis, J. Brack, A. Brüll, V. Bryzgalov, G.P. Capitani, T. Chen, G. Ciullo, M. Contalbrigo, P.F. Dalpiaz, R. De Leo, M. Demey, L. De Nardo, E. De Sanctis, E. Devitsin, P. Di Nezza, M. Düren, M. Ehrenfried, A. Elalaoui-Moulay, G. Elbakian, F. Ellinghaus, U. Elschenbroich, R. Fabbri, A. Fantoni, A. Fechtchenko, L. Felawka, S. Frullani, G. Gapienko, V. Gapienko, F. Garibaldi, K. Garrow, E. Garutti, G. Gavrilov, V. Gharibyan, G. Graw, O. Grebeniouk, L.G. Greeniaus, I.M. Gregor, K.A. Griffioen, K. Hafidi, M. Hartig, D. Hasch, D. Heesbeen, M. Henoch, R. Hertenberger, W.H.A. Hesselink, A. Hillenbrand, M. Hoek, Y. Holler, B. Hommez, G. Iarygin, A. Ivanilov, A. Izotov, H.E. Jackson, A. Jgoun, R. Kaiser, E. Kinney, A. Kisselev, M. Kopytin, V. Korotkov, V. Kozlov, B. Krauss, V.G. Krivokhijine, L. Lagamba, L. Lapikás, A. Laziev, P. Lenisa, P. Liebing, L.A. Linden-Levy, K. Lipka, W. Lorenzon, H. Lu, J. Lu, S. Lu, B.-Q. Ma, B. Maiheu, N.C.R. Makins, Y. Mao, B. Marianski, H. Marukyan, F. Masoli, V. Mexner, N. Meyners, O. Mikloukho, C.A. Miller, Y. Miyachi, V. Muccifora, A. Nagaitsev, E. Nappi, Y. Naryshkin, A. Nass, M. Negodaev, W.-D. Nowak, K. Oganessyan, H. Ohsuga, A. Osborne, N. Pickert, S. Potashov, D.H. Potterveld, M. Raithel, D. Reggiani, P.E. Reimer, A. Reischl, A.R. Reolon, C. Riedl, K. Rith, G. Rosner, A. Rostomyan, L. Rubacek, J. Rubin, D. Ryckbosch, Y. Salomatin, I. Sanjiev, I. Savin, A. Schäfer, C. Schill, G. Schnell, K.P. Schüler, J. Seele, R. Seidl, B. Seitz, R. Shanidze, C. Shearer, T.-A. Shibata, V. Shutov, K. Sinram, W. Sommer, M. Stancari, M. Statera, E. Steffens, J.J.M. Steijger, H. Stenzel, J. Stewart, F. Stinzing, P. Tait, H. Tanaka, S. Taroian, B. Tchuiko, A. Terkulov, A. Tkabladze, A. Trzcinski, M. Tytgat, A. Vandenbroucke, P. van der Nat, G. van der Steenhoven, Y. van Haarlem, M.C. Vetterli, V. Vikhrov, M.G. Vincter, C. Vogel, M. Vogt, J. Volmer, C. Weiskopf, J. Wendland, J. Wilbert, G. Ybeles Smit, Y. Ye, Z. Ye, S. Yen, B. Zihlmann, and P. Zupranski

Subjects
Physics, HERMES experiment, Nuclear and High Energy Physics, Particle physics, Meson, Isovector, 010308 nuclear & particles physics, Isoscalar, Nuclear Theory, Parton, 01 natural sciences, Helicity, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, 010306 general physics
Abstract

Hard exclusive electroproduction of π + π − pairs off hydrogen and deuterium targets has been studied by the HERMES experiment at DESY. Legendre moments 〈 P 1 〉 and 〈 P 3 〉 of the angular distributions of π + mesons in the center-of-mass frame of the pair have been measured for the first time. Their dependence on the π + π − invariant mass can be understood as being due to the interference between relative P -wave (isovector) and S -, D -wave (isoscalar) states of the two pions. The increase in magnitude of 〈 P 1 〉 as Bjorken x increases is interpreted in the framework of generalized parton distributions as an enhancement of flavour non-singlet q q ¯ exchange for larger values of x , which leads to a sizable admixture of isoscalar and isovector pion pairs. In addition, the interference between P -wave and D -wave states separately for transverse and longitudinal pion pairs has been studied. The data indicate that in the f 2 ( 1270 ) region at 〈 Q 2 〉 = 3 GeV 2 higher-twist effects can be as large as the leading-twist longitudinal component.

Published
2004
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29. Short Fatigue Crack Growth at Different Maintenance Times for LZ50 Steel

Author

Bing Yang, S. N. Xiao, B. Q. Ma, and Yong Xiang Zhao

Subjects
Time effect, Axle, Materials science, Mechanics of Materials, Solid mechanics, Crack size, Научно-технический раздел, Growth rate, Growth model, Paris' law, Composite material
Abstract

Based on the average fatigue life of LZ50 axle steel specimens without surface rolling, five maintenance times were determined. Accordingly, five groups of specimens were turned and rolled at above maintenance times and were fatigued using a replica technique. The results show that the crack growth rate is much lower than that before rolling at a given dominant short crack size. The effective short crack density of all specimens decreases significantly after maintenance. However, with the postponement of surface maintenance, the highest effective short crack density for the five studied groups of specimens increases continuously, while the average fatigue life decreases gradually. A maintenance time effect function is presented to refine a short crack growth model described previously. The revifined model can include a significant effect of the maintenance time on short crack growth and predict its patterns at different maintenance times with exiting test results for LZ50 axle steel. На основании средней усталостной долговечности образцов осевой стали LZ50, не подвергавшихся поверхностной обкатке роликами, были определены пять модельных межремонтных циклов. Соответственно пять групп образцов были обточены и обкатаны роликами при вышеуказанных межремонтных циклах и подвергнуты испытанию на усталость по методу реплик. Результаты показывают, что скорость роста трещин гораздо ниже таковой до обкатки роликами при заданном преобладающем размере коротких трещин. Эффективная плотность коротких трещин для всех образцов значительно уменьшается после обработки. Однако если поверхностную обработку вовремя не выполняют, наибольшая эффективная плотность коротких трещин для пяти исследуемых групп образцов непрерывно возрастает, тогда как средняя усталостная долговечность постепенно снижается. Приведена функция, описывающая эффект межремонтных циклов, для уточнения предложенной ранее модели роста коротких трещин. Уточненная модель может учитывать существенное влияние межремонтного цикла на рост коротких трещин и прогнозировать характер их роста при различных межремонтных циклах на основании полученных результатов испытаний осевой стали LZ50.

Published
2015

30. Spin density matrix elements in exclusive $$\omega $$ ω electroproduction on $$^1$$ 1 H and $$^2$$ 2 H targets at 27.5 GeV beam energy

Author

P. Lenisa, A. Trzcinski, L. Lapikás, B. Seitz, S. Frullani, W. Augustyniak, M. Stancari, B. Q. Ma, Frank Ellinghaus, Riccardo Fabbri, V. A. Kozlov, Dirk Ryckbosch, E. R. Kinney, G. Schnell, A. Petrosyan, E. De Sanctis, V. Gharibyan, A. Ivanilov, C. Van Hulse, A. Airapetian, Y. Naryshkin, P. Di Nezza, N. Akopov, I. Lehmann, R. De Leo, H. E. Jackson, M. Diefenthaler, Shan Wang, V. G. Krivokhijine, P. F. Dalpiaz, T. A. Shibata, R. Perez-Benito, D. Zeiler, H. Marukyan, E. Etzelmüller, C. Riedl, G. Karyan, B. Marianski, Y. J. Mao, P. Kravchenko, V. A. Korotkov, W.-D. Nowak, V. A. Gapienko, P. E. Reimer, A. Rostomyan, Klaus Rith, A. Avetissian, S. Joosten, G. Ciullo, A. Kisselev, A. Nass, I. Vilardi, Michael Tytgat, E. Cisbani, G. Gapienko, G. Elbakian, K. P. Schüler, S. Taroian, T. Keri, Luciano Pappalardo, S. I. Manaenkov, Morgan Murray, L. Felawka, Wouter Deconinck, L. Lagamba, H. P. Blok, A. Movsisyan, David Mahon, G. P. Capitani, Wolfgang Lorenzon, V. Vikhrov, V. Bryzgalov, Y. Holler, Andreas Schäfer, Ivana Hristova, J. J. M. Steijger, S. Yaschenko, Michael Düren, F. Garibaldi, Z. Akopov, D. Hasch, M. Contalbrigo, M. Hartig, P. Zupranski, Y. Van Haarlem, R. Truty, S. Yen, Ralf Kaiser, E. Steffens, G. Gavrilov, A. R. Reolon, M. Stahl, Adel Terkulov, D. Gabbert, M. Ehrenfried, M. Statera, B. Zihlmann, Alexander Borissov, and M. Capiluppi

Subjects
Physics, Density matrix, HERMES experiment, Particle physics, Physics and Astronomy (miscellaneous), Meson, 010308 nuclear & particles physics, Hadron, Elementary particle, 01 natural sciences, Helicity, Omega, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Spin-flip, Nuclear Experiment, 010306 general physics, Engineering (miscellaneous)
Abstract

Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive ρ 0 electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy and unpolarized hydrogen and deuterium targets. Eight (fifteen) SDMEs that are related (unrelated) to the longitudinal polarization of the beam are extracted in the kinematic region 1

Published
2014
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31. Beam-helicity asymmetry in associated electroproduction of real photons ep → eγπN in the Δ-resonance region

Author

Valeria Muccifora, G. Gapienko, Salvatore Frullani, Shan Wang, A. Rostomyan, A. R. Reolon, A. Avetissian, H. P. Blok, B. Marianski, M. Ehrenfried, M. Statera, C. Van Hulse, P. E. Reimer, Wolfgang Lorenzon, Y. Van Haarlem, W. Augustyniak, Zhenyu Ye, Ivana Hristova, I. Vilardi, Adel Terkulov, T. A. Shibata, N. C. R. Makins, V. Gharibyan, R.O. Avakian, H. Böttcher, J. Garay Garcia, P. F. Dalpiaz, S. Joosten, Y. Miyachi, A. Kisselev, V. Kozlov, V. A. Korotkov, David Mahon, Dirk Ryckbosch, S. Yen, M. Diefenthaler, Ralf Kaiser, Andreas Mussgiller, P. Lenisa, V. A. Gapienko, A. Trzcinski, E. Steffens, C. Riedl, H. Marukyan, Luciano Pappalardo, Frank Ellinghaus, J. Burns, E. De Sanctis, G. Gavrilov, Y. Salomatin, T. Keri, Franco Garibaldi, Andreas Schäfer, E. R. Kinney, B. Zihlmann, S. Yaschenko, G. Elbakian, Alexander Borissov, D. Hasch, Riccardo Fabbri, S. I. Manaenkov, Y. Naryshkin, B. Q. Ma, C. A. Miller, W.-D. Nowak, V. Vikhrov, Michael Tytgat, E. Cisbani, Klaus Rith, V. Zagrebelnyy, J. J. M. Steijger, F. Giordano, R. De Leo, Morgan Murray, Michael Düren, J. Bowles, S. Taroian, I. Brodski, H. E. Jackson, V. G. Krivokhijine, Stephen V. Gliske, E. Avetisyan, E. Etzelmüller, R. Perez-Benito, A. Nass, V. Bryzgalov, L. Lagamba, G. P. Capitani, J. G. Rubin, I. Lehmann, B. Seitz, Xianguo Lu, M. Negodaev, M. Hartig, P. Di Nezza, M. Stahl, A. Airapetian, F. Stinzing, G. Schnell, P. Zupranski, A. Ivanilov, G. Rosner, R. Truty, G. Ciullo, A. Movsisyan, Y. Holler, A. Petrosyan, Wouter Deconinck, L. Lapikás, P. Kravchenko, J. Stewart, N. Akopov, M. Contalbrigo, G. Karyan, Y. J. Mao, and E. C. Aschenauer

Subjects
25.30.-c Lepton-induced reactions, Lepton-Nucleon Scattering, QCD, 13.88.+e - Polarization in interactions and scattering, Photon production, Nuclear and High Energy Physics, Photon, media_common.quotation_subject, HERA, LIMIT, 01 natural sciences, Asymmetry, CROSS-SECTIONS, Nuclear physics, Recoil, DEPENDENCE, Polarization, 0103 physical sciences, 010306 general physics, VIRTUAL COMPTON-SCATTERING, media_common, Quantum chromodynamics, Physics, 010308 nuclear & particles physics, Polarization (waves), Helicity, Amplitude, Physics and Astronomy, SPIN, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics
Abstract

The beam-helicity asymmetry in associated electroproduction of real photons, ep -> aEuro parts per thousand e gamma pi N , in the Delta(1232)-resonance region is measured using the longitudinally polarized Hera positron beam and an unpolarized hydrogen target. Azimuthal Fourier amplitudes of this asymmetry are extracted separately for two channels, ep -> aEuro parts per thousand e gamma pi(0) p and ep -> aEuro parts per thousand e gamma pi(+) n, from a data set collected with a recoil detector. All asymmetry amplitudes are found to be consistent with zero.

Published
2014
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32. Reevaluation of the parton distribution of strange quarks in the nucleon

Author

S. Belostotski, V. Bryzgalov, M. Diefenthaler, Paolo Lenisa, S. Joosten, A. Kisselev, V. Kozlov, Luciano Pappalardo, S. Frullani, D. Hasch, Dirk Ryckbosch, P. Zupranski, C. Riedl, Y. Miyachi, W. Augustyniak, B. Marianski, Frank Ellinghaus, T. Keri, M. Ehrenfried, E. R. Kinney, Adel Terkulov, Xianguo Lu, W.-D. Nowak, M. Hoek, G. Gapienko, V. Vikhrov, Morgan Murray, M. Negodaev, G. Rosner, R. Truty, A. Trzcinski, M. Hartig, Y. Naryshkin, I. Vilardi, D. Gabbert, A. Ivanilov, H. P. Blok, E. Avetisyan, P. Di Nezza, Zhenyu Ye, H. E. Jackson, Wolfgang Lorenzon, A. Nass, M. Stahl, V. Gharibyan, V. G. Krivokhijine, B. Zihlmann, Ivana Hristova, S. Yaschenko, Alexander Borissov, B. Seitz, Y. Holler, J. G. Rubin, M. Capiluppi, C. Van Hulse, J. J. M. Steijger, I. Lehmann, Michael Düren, David Mahon, Valeria Muccifora, M. Statera, E. De Sanctis, Franco Garibaldi, Andreas Schäfer, P. E. Reimer, A. Movsisyan, E. Etzelmüller, L. Lapikás, C. Vogel, Shan Wang, Y. Van Haarlem, J. Burns, V. A. Korotkov, A. Rostomyan, A. R. Reolon, A. Avetissian, K. Rith, A. Petrosyan, G. Elbakian, S. I. Manaenkov, A. Airapetian, D. Veretennikov, Y. Salomatin, F. Stinzing, Stephen V. Gliske, L. Felawka, B. Q. Ma, G. P. Capitani, H. Marukyan, L. Lagamba, Z. Akopov, R. De Leo, Andreas Mussgiller, G. Ciullo, V. A. Gapienko, R. Perez-Benito, G. Schnell, J. Garay Garcia, S. Yen, Ralf Kaiser, Wouter Deconinck, E. Steffens, G. Gavrilov, M. Contalbrigo, F. Giordano, E. C. Aschenauer, P. F. Dalpiaz, T. A. Shibata, N. Akopov, G. Karyan, Y. J. Mao, P. Kravchenko, Michael Tytgat, E. Cisbani, and S. Taroian

Subjects
HERMES experiment, Quark, Nuclear and High Energy Physics, Strange quark, Particle physics, Distribution (number theory), strangeness [nucleon], Nuclear Theory, FOS: Physical sciences, Parton, HERMES, 01 natural sciences, sea [strangeness], High Energy Physics - Experiment, x-dependence, Nuclear physics, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), semi-inclusive reaction [deep inelastic scattering], 0103 physical sciences, ddc:530, 010306 general physics, Nuclear Experiment, HIGH-ENERGY COLLISIONS, Physics, 010308 nuclear & particles physics, Scattering, High Energy Physics - Phenomenology, DESY HERA Stor, Physics and Astronomy, High Energy Physics::Experiment, multiplicity [K], deep inelastic scattering [electron deuteron], Nucleon, distribution function [parton]
Abstract

An earlier extraction from the HERMES experiment of the polarization-averaged parton distribution of strange quarks in the nucleon has been reevaluated using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering obtained with a kinematically more comprehensive method of correcting for experimental effects. General features of the distribution are confirmed, but the rise at low $x$ is less pronounced than previously reported.

Published
2014
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33. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

Author

J. Burns, G. Gapienko, J. J. M. Steijger, Michael Düren, Riccardo Fabbri, K. Rith, H. E. Jackson, Michael Tytgat, E. Cisbani, M. Stancari, M. Golembiovskaya, D. Veretennikov, T. Keri, V. G. Krivokhijine, E. Avetisyan, M. Capiluppi, A. Petrosyan, G. Ciullo, S. Taroian, A. Hillenbrand, M. Negodaev, L. De Nardo, Zhenyu Ye, P. E. Reimer, M. Contalbrigo, Shan Wang, S. Yaschenko, I. Vilardi, C. Hadjidakis, Martin Raithel, P. Di Nezza, Frank Ellinghaus, E. C. Aschenauer, W.-D. Nowak, B. Seitz, E. Nappi, J. Bowles, V. Vikhrov, P. Lenisa, E. R. Kinney, B. Marianski, V. A. Korotkov, V. A. Gapienko, C. A. Miller, E. De Sanctis, V. Gharibyan, A. Martinez de la Ossa, Y. Naryshkin, Morgan Murray, N. Bianchi, A. Rostomyan, V. Zagrebelnyy, A. Fantoni, A. Avetissian, D. Gabbert, L. Lapikás, David Mahon, P. F. Dalpiaz, Andreas Schäfer, A. Trzcinski, Stephen V. Gliske, S. Joosten, Wouter Deconinck, M. Ehrenfried, A. Kisselev, L. Felawka, F. Giordano, N. C. R. Makins, G. Elbakian, L. Lagamba, A. R. Reolon, Y. Miyachi, S. Belostotski, V. Bryzgalov, S. I. Manaenkov, Vitaly Shutov, H. P. Blok, S. Frullani, D. Hasch, G. P. Capitani, A. Airapetian, Wolfgang Lorenzon, Dirk Ryckbosch, W. Yu, P. Kravchenko, C. Van Hulse, R. Perez-Benito, Andreas Mussgiller, Ivana Hristova, M. Statera, J. Stewart, W. Augustyniak, D. Zeiler, S. Yen, T. A. Shibata, V. A. Kozlov, R.O. Avakian, F. Stinzing, Ralf Kaiser, G. Schnell, E. Steffens, G. Gavrilov, M. Hartig, P. Zupranski, Z. Akopov, C. Riedl, M. Hoek, N. Akopov, J. G. Rubin, I. Lehmann, G. Rosner, R. Truty, G. Karyan, Y. J. Mao, Adel Terkulov, A. López Ruiz, Y. Van Haarlem, Y. Salomatin, B. Q. Ma, R. De Leo, B. Zihlmann, L. L. Pappalardo, Alexander Borissov, F. Sanftl, M. Diefenthaler, H. Marukyan, A. Movsisyan, A. Ivanilov, Y. Holler, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HERMES, Student Lab and Education, and (Astro)-Particles Physics

Subjects
HERMES experiment, Hadron, Nuclear Theory, analizing power, Electron, 01 natural sciences, sivers asymmetries, High Energy Physics - Experiment, CROSS-SECTIONS, DEEP-INELASTIC SCATTERING, High Energy Physics - Experiment (hep-ex), hard scattering, arrow-p, Mathematics::Probability, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], chiral-odd contibution, Nuclear Experiment (nucl-ex), cross-sections, Nuclear Experiment, ARROW-P, media_common, Physics, polarized proton-beam, POLARIZED PROTON-BEAM, CHIRAL-ODD CONTRIBUTION, SIVERS ASYMMETRIES, ANALYZING POWER, 200 GEV/C, PI(0) PRODUCTION, HARD SCATTERING, deep-inelastic scattering, ddc:530, PI(0) production, PHYSICS, NUCLEAR, Transverse plane, symbols, Particle physics, Nuclear and High Energy Physics, media_common.quotation_subject, Mathematics::Analysis of PDEs, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Asymmetry, Mathematics::Numerical Analysis, Nuclear physics, symbols.namesake, Pion, 0103 physical sciences, Feynman diagram, SDG 7 - Affordable and Clean Energy, 010306 general physics, 010308 nuclear & particles physics, Deep inelastic scattering, 530 Physik, Physics and Astronomy, High Energy Physics::Experiment
Abstract

Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\psi$ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum relative to the direction of the incident beam, and the Feynman variable $x_F$. The $\sin(\psi)$ amplitudes are positive for positive pions and kaons, slightly negative for negative pions and consistent with zero for negative kaons, with particular transverse-momentum but weak $x_F$ dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer., Comment: 10 pages, 5 figures

Published
2014
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34. Spin density matrix elements in exclusive omega electroproduction on H-1 and H-2 targets at 27.5 GeV beam energy

Author

Airapetian, A., Akopov, N., Akopov, Z., Augustyniak, W., Avetissian, A., Blok, H. P., Borissov, A., Bryzgalov, V., Capiluppi, Marco, Capitani, G. P., Cisbani, E., Ciullo, Giuseppe, Contalbrigo, Marco, Dalpiaz, P. F., Deconinck, W., De Leo, R., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Düren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Etzelmüller, E., Fabbri, R., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Hartig, M., Hasch, D., Holler, Y., Hristova, I., Ivanilov, A., Jackson, H. E., Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Krivokhijine, V. G., Lagamba, L., Lapikás, L., Lehmann, I., Lenisa, Paolo, Lorenzon, W., B. Q., Ma, Mahon, D., Manaenkov, S. I., Mao, Y., Marianski, B., Marukyan, H., Movsisyan, A., Murray, M., Naryshkin, Y., Nass, A., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Petrosyan, A., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rostomyan, A., Ryckbosch, D., Schäfer, A., Schnell, G., Schüler, K. P., Seitz, B., Shibata, T. A., Stahl, M., Stancari, Michelle Dawn, Statera, Marco, Steffens, E., Steijger, J. J. M., Taroian, S., Terkulov, A., Truty, R., Trzcinski, A., Tytgat, M., Van Haarlem, Y., Van Hulse, C., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Yen, S., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
13.60.-r Photon and charged-lepton interactions with hadrons, 29.27.Hj Polarized beams, 13.60.-r Photon and charged-lepton interactions with hadrons, 34.80.Nz Spin dependence of cross sections, polarized beam experiments, 29.27.Hj Polarized beams, 34.80.Nz Spin dependence of cross sections, NO
Published
2014

35. Azimuthal distributions of charged hadrons, pions, and kaons produced in deep-inelastic scattering off unpolarized protons and deuterons

Author

A. Trzcinski, J. Burns, N. C. R. Makins, S. Frullani, A. Hillenbrand, Y. Imazu, K. Rith, Dirk Ryckbosch, Adel Terkulov, V. A. Gapienko, A. Ivanilov, Y. Holler, S. Yen, G. Gapienko, J. Bowles, J. G. Rubin, David Mahon, M. Golembiovskaya, Ralf Kaiser, F. Sanftl, I. Lehmann, Michael Tytgat, E. Cisbani, Andreas Schäfer, A. Movsisyan, C. A. Miller, W. Yu, F. Giordano, Wouter Deconinck, V. Zagrebelnyy, B. Marianski, B. Zihlmann, G. Ciullo, W. Augustyniak, G. Gavrilov, Alexander Borissov, H. E. Jackson, C. Van Hulse, V. G. Krivokhijine, H. P. Blok, T. A. Shibata, M. Statera, R.O. Avakian, A. Airapetian, M. Capiluppi, Arne Vandenbroucke, M. Stancari, Alessandra Fantoni, Y. Naryshkin, W.-D. Nowak, Shan Wang, Wolfgang Lorenzon, D. Zeiler, E. De Sanctis, Franco Garibaldi, P. F. Dalpiaz, L. Manfré, P. E. Reimer, M. Hoek, Ivana Hristova, A. Martinez de la Ossa, A. López Ruiz, D. Veretennikov, Paolo Lenisa, S. Yaschenko, S. Joosten, M. Negodaev, I. Vilardi, V. A. Korotkov, Eugenio Nappi, A. Kisselev, V. Kozlov, Luciano Pappalardo, Y. Van Haarlem, A. Rostomyan, A. R. Reolon, A. Avetissian, Y. J. Mao, P. Kravchenko, L. Lapikás, T. Keri, M. Diefenthaler, A. Nass, H. S. Jo, F. Stinzing, J. Stewart, G. Schnell, M. Contalbrigo, E. Avetisyan, G. Elbakian, S. I. Manaenkov, Martin Raithel, E. C. Aschenauer, R. Perez-Benito, V. Vikhrov, M. Hartig, A. Petrosyan, P. Di Nezza, C. Riedl, Morgan Murray, B. Seitz, D. Hasch, K. P. Schüler, P. Zupranski, G. Rosner, R. Truty, N. Akopov, S. Belostotski, G. Karyan, V. Bryzgalov, Frank Ellinghaus, E. R. Kinney, Y. Salomatin, B. Q. Ma, H. Marukyan, R. De Leo, Stephen V. Gliske, L. Felawka, L. Lagamba, Z. Akopov, L. De Nardo, Zhenyu Ye, V. Gharibyan, J. J. M. Steijger, Michael Düren, Cynthia Marie Hadjidakis, and Y. Miyachi

Subjects
Drell-Yan process, HERMES experiment, generalized parton distribution, Nuclear Theory, Hadron, HERMES, Parton, 01 natural sciences, multiple production [charged particle], High Energy Physics - Experiment, HARD-SCATTERING, High Energy Physics - Experiment (hep-ex), semi-inclusive reaction [deep inelastic scattering], transverse momentum [parton], HERMES EXPERIMENT, deep inelastic scattering [positron p], Collins, Nuclear Experiment (nucl-ex), Nuclear Experiment, electroproduction [pi], Physics, FINAL-STATE INTERACTIONS, ANGULAR-DISTRIBUTIONS, PARTON-MODEL, DUAL RADIATOR RICH, angular dependence, modulation, DESY HERA Stor, SPIN PRODUCTION ASYMMETRIES, Nucleon, Quark, Nuclear and High Energy Physics, Particle physics, DRELL-YAN, FOS: Physical sciences, Nuclear physics, angular distribution [charged particle], Pion, 0103 physical sciences, ddc:530, PHYSICS EVENT GENERATION, TRANSVERSE-MOMENTUM, 010306 general physics, deep inelastic scattering [lepton deuteron], 27.6 GeV, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, polarization [quark], Deep inelastic scattering, Physics and Astronomy, electroproduction [K], deep inelastic scattering [electron p], High Energy Physics::Experiment, experimental results
Abstract

The azimuthal cos{\phi} and cos2{\phi} modulations of the distribution of hadrons produced in unpolarized semi-inclusive deep-inelastic scattering of electrons and positrons off hydrogen and deuterium targets have been measured in the HERMES experiment. For the first time these modulations were determined in a four-dimensional kinematic space for positively and negatively charged pions and kaons separately, as well as for unidentified hadrons. These azimuthal dependences are sensitive to the transverse motion and polarization of the quarks within the nucleon via, e.g., the Cahn, Boer-Mulders and Collins effects.

Published
2013
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36. Multiplicities of charged pions and kaons from semi-inclusive deep-inelastic scattering by the proton and the deuteron

Author

N. Akopov, G. Karyan, V. A. Korotkov, Y. J. Mao, A. Trzcinski, Wouter Deconinck, Frank Ellinghaus, E. R. Kinney, A. Petrosyan, W.-D. Nowak, Andreas Mussgiller, David Mahon, J. Burns, Vitaly Shutov, H. P. Blok, G. Elbakian, L. Manfré, A. Martinez de la Ossa, P. E. Reimer, Wolfgang Lorenzon, Andreas Schäfer, C. A. Miller, Ivana Hristova, Eugenio Nappi, L. De Nardo, Alessandra Fantoni, S. Yaschenko, S. I. Manaenkov, A. Hillenbrand, Y. Imazu, L. Lagamba, M. Diefenthaler, I. Vilardi, S. Belostotski, M. Hoek, Shan Wang, B. Zihlmann, P. F. Dalpiaz, Z. Akopov, Nagao Kobayashi, Zhenyu Ye, V. Zagrebelnyy, V. Bryzgalov, F. Garibaldi, H. S. Jo, W. Augustyniak, Riccardo Fabbri, C. Van Hulse, Alexander Borissov, A. López Ruiz, D. Gabbert, M. Statera, K. Rith, V. Gharibyan, Y. Naryshkin, M. Stancari, Y. Van Haarlem, M. Capiluppi, J. Bowles, I. Brodski, D. Zeiler, C. Vogel, Y. Salomatin, A. Nass, M. Golembiovskaya, A. Rostomyan, A. R. Reolon, A. Avetissian, H. E. Jackson, Stephen V. Gliske, T. Keri, M. Contalbrigo, D. Veretennikov, V. G. Krivokhijine, B. Q. Ma, Martin Raithel, G. Gapienko, J. J. M. Steijger, E. C. Aschenauer, H. Marukyan, R. De Leo, L. Felawka, B. Marianski, Michael Düren, E. De Sanctis, C. Riedl, W. Yu, G. P. Capitani, Michael Tytgat, Adel Terkulov, M. Ehrenfried, Cynthia Marie Hadjidakis, Y. Miyachi, Paolo Lenisa, E. Cisbani, S. Joosten, T. A. Shibata, A. Kisselev, V. Kozlov, V. Gapienko, R.O. Avakian, Morgan Murray, S. Taroian, S. Yen, Luciano Pappalardo, B. Seitz, Andrey V. Izotov, Ralf Kaiser, E. Avetisyan, N. C. R. Makins, E. Steffens, G. Gavrilov, S. Frullani, Dirk Ryckbosch, R. Perez-Benito, B. Maiheu, F. Giordano, G. Ciullo, J. G. Rubin, I. Lehmann, M. Hartig, P. Di Nezza, D. Hasch, M. Negodaev, A. Airapetian, F. Stinzing, G. Schnell, A. Ivanilov, L. Lapikás, P. Kravchenko, J. Stewart, Y. Holler, P. Zupranski, G. Rosner, R. Truty, F. Sanftl, and A. Movsisyan

Subjects
HERMES experiment, AZIMUTHAL DEPENDENCE, FRAGMENTATION FUNCTIONS, Hadron, Parton, HERMES, momentum transfer dependence, 01 natural sciences, 7. Clean energy, CROSS-SECTIONS, High Energy Physics - Experiment, 13.60.-r, 13.60.Le, 13.87.Fh, 14.20.Dh, High Energy Physics - Experiment (hep-ex), semi-inclusive reaction [deep inelastic scattering], LEPTOPRODUCTION, MONTE-CARLO, deep inelastic scattering [positron p], Nuclear Experiment (nucl-ex), Nuclear Experiment, electroproduction [pi], Physics, HERA, fragmentation [quark], DESY HERA Stor, CHAMBERS, FACTORIZATION, Quark, Nuclear and High Energy Physics, Particle physics, Meson, PARTON MODEL, FOS: Physical sciences, x-dependence, Nuclear physics, Pion, 0103 physical sciences, ddc:530, 010306 general physics, deep inelastic scattering [lepton deuteron], 010308 nuclear & particles physics, 27.6 GeV, High Energy Physics::Phenomenology, ELECTROPRODUCTION, Deep inelastic scattering, multiplicity: measured [charged particle], Physics and Astronomy, electroproduction [K], deep inelastic scattering [electron p], High Energy Physics::Experiment, experimental results
Abstract

Multiplicities in semi-inclusive deep-inelastic scattering are presented for each charge state of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ and ${\mathrm{K}}^{\ifmmode\pm\else\textpm\fi{}}$ mesons. The data were collected by the HERMES experiment at the HERA storage ring using 27.6 GeV electron and positron beams incident on a hydrogen or deuterium gas target. The results are presented as a function of the kinematic quantities ${x}_{\mathrm{B}}$, ${Q}^{2}$, $z$, and ${P}_{h\ensuremath{\perp}}$. They represent a unique data set for identified hadrons that will significantly enhance our understanding of the fragmentation of quarks into final-state hadrons in deep-inelastic scattering.

Published
2012
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37. Measurements of double-spin asymmetries associated with deeply virtual Compton scattering on a transversely polarized hydrogen target

Author

V. A. Korotkov, David Mahon, V. A. Kozlov, Andreas Schäfer, Y. J. Mao, G. Ciullo, W. Augustyniak, G. Elbakian, V. Zagrebelnyy, E. De Sanctis, Paolo Lenisa, S. Joosten, V. Gharibyan, G. Gapienko, A. Kisselev, S. I. Manaenkov, P. E. Reimer, Klaus Rith, A. R. Reolon, J. Burns, Y. Naryshkin, P. Kravchenko, M. Hoek, N. C. R. Makins, Z. Akopov, X. R. Lu, M. Contalbrigo, A. Movsisyan, S. Belostotski, V. Bryzgalov, A. Trzcinski, V. A. Gapienko, Martin Raithel, E. C. Aschenauer, N. Bianchi, F. Garibaldi, S. Frullani, B. Marianski, A. Nass, Y. Holler, Adel Terkulov, I. Brodski, E. Avetisyan, Dirk Ryckbosch, S. Yen, Y. Imazu, Ralf Kaiser, P. F. Dalpiaz, H. S. Jo, M. Golembiovskaya, N. Akopov, B. Seitz, E. Nappi, C. A. Miller, Morgan Murray, G. Karyan, A. Fantoni, E. Steffens, Stephen V. Gliske, D. Gabbert, G. Gavrilov, C. Riedl, J. Bowles, Shan Wang, L. Felawka, Wouter Deconinck, L. Lagamba, Riccardo Fabbri, D. Veretennikov, Michael Tytgat, E. Cisbani, G. P. Capitani, M. Statera, D. Zeiler, S. Taroian, P. Di Nezza, F. Giordano, M. Capiluppi, C. B. Van Hulse, B. Zihlmann, Xianguo Lu, M. Negodaev, L. L. Pappalardo, T. A. Shibata, R. Perez-Benito, A. Ivanilov, H. E. Jackson, Alexander Borissov, V. G. Krivokhijine, R.O. Avakian, Vitaly Shutov, H. P. Blok, A. Rostomyan, A. Avetissian, T. Keri, Frank Ellinghaus, Wolfgang Lorenzon, E. R. Kinney, Ivana Hristova, S. Yaschenko, V. Vikhrov, L. Manfré, K. P. Schüler, P. Zupranski, J. G. Rubin, I. Lehmann, G. Rosner, R. Truty, M. Hartig, A. Airapetian, F. Stinzing, A. López Ruiz, Y. Van Haarlem, Andreas Mussgiller, Y. Salomatin, B. Q. Ma, M. Ehrenfried, H. Marukyan, R. De Leo, Y. Miyachi, D. Hasch, G. Schnell, L. Lapikás, J. J. M. Steijger, Michael Düren, W.-D. Nowak, M. Stancari, A. Martinez de la Ossa, L. De Nardo, Zhenyu Ye, and I. Vilardi

Subjects
Nuclear and High Energy Physics, Photon, EVOLUTION KERNELS, HERA, FOS: Physical sciences, HERMES, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), GPDs, GENERALIZED PARTON DISTRIBUTIONS, 0103 physical sciences, ddc:530, NUCLEON, 010306 general physics, DVCS, GPDs, HERMES experiments, Transversely polarized hydrogen target, Physics, Quantum chromodynamics, 010308 nuclear & particles physics, Compton scattering, Transversely polarized hydrogen target, HERMES experiments, Polarization (waves), QCD, Helicity, Transverse plane, Physics and Astronomy, ELECTRON STORAGE-RING, DVCS, Nucleon
Abstract

Double-spin asymmetries in exclusive electroproduction of real photons from a transversely polarized hydrogen target are measured with respect to the product of target polarization with beam helicity and beam charge, and with respect to the product of target polarization with beam helicity alone. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe--Heitler process. They are related to the real part of the same combination of Compton form factors as that determining the previously published transverse target single-spin asymmetries through the imaginary part. The results for the double-spin asymmetries are found to be compatible with zero within the uncertainties of the measurement, and are not incompatible with the predictions of the only available GPD-based calculation., Comment: 9 pages, 4 figures, and 3 tables

Published
2011
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38. Transverse spin structure of the nucleon through target single-spin asymmetry in semi-inclusive deep-inelastic (e, e’ $ \pi^{\pm}_{}$ ) reaction at Jefferson Lab

Author

A. Prokudin, Y. J. Mao, Mauro Anselmino, C. W. de Jager, X. Jiang, J. P. Chen, B. Q. Ma, Xin Qian, E. Chudakov, Andrei Afanasev, M. Huang, Marc Schlegel, H. Avakian, Z. E. Meziani, L. Zhu, Z. G. Xiao, Paul Souder, G. D. Cates, Jen-Chieh Peng, Yujie Qiang, K. S. Kumar, E. Cisbani, F. Garibaldi, B. T. Hu, Yuzhen Ye, Leonard Gamberg, H. J. Lu, X. M. Li, and Haiyan Gao

Subjects
Quark, Physics, Particle physics, Angular momentum, media_common.quotation_subject, Nuclear Theory, General Physics and Astronomy, Deep inelastic scattering, Asymmetry, Particle identification, Nuclear physics, High Energy Physics - Phenomenology, Pion, High Energy Physics::Experiment, Neutron, Nuclear Experiment, Nucleon, media_common
Abstract

Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to perform precision studies of the transverse spin and transverse-momentum-dependent structure in the valence quark region for both the proton and the neutron. In this paper, we focus our discussion on a recently approved experiment on the neutron as an example of the precision studies planned at JLab. The new experiment will perform precision measurements of target Single Spin Asymmetries (SSA) from semi-inclusive electro-production of charged pions from a 40-cm long transversely polarized $^3$He target in Deep-Inelastic-Scattering kinematics using 11 and 8.8 GeV electron beams. This new coincidence experiment in Hall A will employ a newly proposed solenoid spectrometer (SoLID). The large acceptance spectrometer and the high polarized luminosity will provide precise 4-D ($x$, $z$, $P_T$ and $Q^2$) data on the Collins, Sivers, and pretzelocity asymmetries for the neutron through the azimuthal angular dependence. The full 2$\pi$ azimuthal angular coverage in the lab is essential in controlling the systematic uncertainties. The results from this experiment, when combined with the proton Collins asymmetry measurement and the Collins fragmentation function determined from the e$^+$e$^-$ collision data, will allow for a quark flavor separation in order to achieve a determination of the tensor charge of the d quark to a 10% accuracy. The extracted Sivers and pretzelocity asymmetries will provide important information to understand the correlations between the quark orbital angular momentum and the nucleon spin and between the quark spin and nucleon spin., Comment: 23 pages, 13 figures, minor corrections, matches published version

Published
2011
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39. Leading-order determination of the gluon polarization from high-p T hadron electroproduction

Author

Airapetian, A., Akopov, N., Akopov, Z., Amarian, M., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Ball, B., Belostotski, S., Bianchi, N., Blok, H. P., Bottcher, H., Borissov, A., Bowles, J., Bryzgalov, V., Burns, J., Capiluppi, Marco, Capitani, G. P., Cisbani, E., Ciullo, G., Contalbrigo, Marco, Ferretti, Paola, Deconinck, W., Leo, R. D., Nardo, L. D., Sanctis, E. D., Diefenthaler, M., Nezza, P. D., Duren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gavrilov, G., Gharibyan, V., Giordano, Francesca, Gliske, S., Guler, H., Guzey, V., Haan, S., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Jackson, H. E., H. S., Jo, Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Korotkov, V., Kozlov, V., Kravchenko, P., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, Paolo, Ruiz, A. L., Lorenzon, W., X. G., Lu, X. R., Lu, B. Q., Ma, Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., de la Ossa, A. M., Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Muccifora, V., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Raithel, M., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Schafer, A., Schnell, G., Schuler, K. P., Shanidze, R., Shibata, T. A., Shutov, V., Stancari, Michelle Dawn, Statera, Marco, Steffens, E., Steijger, J. J. M., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., Vandenbroucke, A., Haarlem, Y. V., Hulse, C. V., Varanda, M., Veretennikov, D., Vikhrov, V., Vilardi, I., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yu, W., Zeiler, D., Zihlmann, B., and Zupranski, P.

Subjects
Nuclear and High Energy Physics, Particle physics, High Energy Physics::Lattice, Nuclear Theory, Lepton-Nucleon Scattering, Hadron, Monte Carlo method, FOS: Physical sciences, neutron spin structure, transverse momentum, 01 natural sciences, High Energy Physics - Experiment, NO, High Energy Physics - Experiment (hep-ex), deep inelastic scattering, 0103 physical sciences, ddc:530, Nuclear Experiment, 010306 general physics, s Hermes experiment, Lepton-Nucleon Scattering, deep inelastic scattering, neutron spin structure, dependent structure functions, electron storage ring, parton distribution,s Hermes experiment, transverse momentum, proton scattering, EP scattering, Physics, electron storage ring, dependent structure functions, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, EP scattering, HERA, Polarization (waves), parton distribution, Gluon, Deuterium, proton scattering, Transverse momentum, High Energy Physics::Experiment, Nucleon
Abstract

Longitudinal double-spin asymmetries of charged hadrons with high transverse momentum $p_T$ have been measured in electroproduction using the \hermes\ detector at \hera. Processes involving gluons in the nucleon have been enhanced relative to others by selecting hadrons with $p_T$ typically above 1 GeV. In this kinematic domain the gluon polarization has been extracted in leading order making use of the model embedded in the Monte Carlo Generator \Pythia\ 6.2. The gluon polarization obtained from single inclusive hadrons in the $p_T$ range 1 GeV $< p_T

Published
2010
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40. Effects of transversity in deep-inelastic scattering by polarized protons

Author

N. C. R. Makins, B. Seitz, U. Elschenbroich, Stephen V. Gliske, G. Gapienko, L. Felawka, G. P. Capitani, P. B. van der Nat, S. Frullani, R. Lamb, F. Sanftl, G. Hill, N. Pickert, Dirk Ryckbosch, Y. J. Mao, P. Kravchenko, J. G. Rubin, A. Movsisyan, C. A. Miller, I. Lehmann, L. Lapikás, Xianguo Lu, M. Negodaev, D. Veretennikov, M. Statera, Y. Holler, Alessandra Fantoni, M. Hoek, S. Belostotski, D. Gabbert, A. Trzcinski, V. A. Gapienko, D. Zeiler, E. De Sanctis, J. Stewart, Y. Salomatin, C. Vogel, V. Bryzgalov, F. Garibaldi, Shan Wang, P. E. Reimer, W. Yu, Paolo Lenisa, L. A. Linden-Levy, S. Joosten, F. Giordano, A. Nass, P. Zupranski, A. Kisselev, J. Burns, Wouter Deconinck, S. Yen, V. A. Korotkov, G. Schnell, Frank Ellinghaus, E. R. Kinney, Hengqiang Ye, P. F. Dalpiaz, Adel Terkulov, T. A. Shibata, C. B. Van Hulse, B. Q. Ma, V. Kozlov, M. Ehrenfried, Luciano Pappalardo, K. Rith, A. Rostomyan, A. R. Reolon, E. Avetisyan, Ralf Kaiser, A. Avetissian, A. Ivanilov, R.O. Avakian, H. S. Jo, H. Marukyan, R. De Leo, G. Ciullo, M. Golembiovskaya, E. Steffens, N. Akopov, G. Elbakian, M. Hartig, G. Karyan, G. Rosner, S. I. Manaenkov, P. Di Nezza, Riccardo Fabbri, W. Augustyniak, M. Diefenthaler, A. López Ruiz, B. Zihlmann, M. Contalbrigo, Michael Tytgat, E. Cisbani, M. Stancari, Alessandro Bacchetta, H. E. Jackson, Martin Raithel, Alexander Borissov, Hasko Stenzel, M. Capiluppi, Y. Van Haarlem, S. Taroian, Nicola Bianchi, T. Keri, R. Perez-Benito, A. Hillenbrand, Y. Imazu, B. Marianski, X. R. Lu, J. Bowles, A. Airapetian, Andreas Mussgiller, F. Stinzing, V. Vikhrov, I. Vilardi, S. Yaschenko, L. De Nardo, Zhenyu Ye, E. C. Aschenauer, Morgan Murray, V. Gharibyan, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, J. J. M. Steijger, Michael Düren, L. Lagamba, Z. Akopov, Nagao Kobayashi, David Mahon, Andreas Schäfer, Y. Naryshkin, C. Riedl, Vitaly Shutov, H. P. Blok, Wolfgang Lorenzon, W.-D. Nowak, L. Manfré, A. Martinez de la Ossa, Ivana Hristova, Eugenio Nappi, and I. Brodsky

Subjects
Nuclear and High Energy Physics, Antiparticle, Meson, Hadron, FOS: Physical sciences, HERMES, Inelastic scattering, COLLINS, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, ASYMMETRIES, LEPTOPRODUCTION, 0103 physical sciences, DISTRIBUTIONS, ddc:530, QUARKS, 010306 general physics, NUCLEON, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Scattering, Collins function, Deep inelastic scattering, QCD, Polarized structure functions, TARGET, Physics and Astronomy, Single-spin asymmetries, Transversity, Antimatter, Semi-inclusive DIS, High Energy Physics::Experiment, Atomic physics
Abstract

Single-spin asymmetries for pions and charged kaons are measured in semi-inclusive deep-inelastic scattering of positrons and electrons off a transversely nuclear-polarized hydrogen target. The dependence of the cross section on the azimuthal angles of the target polarization (phi_S)and the produced hadron (phi) is found to have a substantial sin(phi+phi_S) modulation for the production of pi+, pi- and K+. This Fourier component can be interpreted in terms of non-zero transversity distribution functions and non-zero favored and disfavored Collins fragmentation functions with opposite sign. For pi0 and K- production the amplitude of this Fourier component is consistent with zero., Comment: 7 pages, 3 figures

Published
2010
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41. Separation of contributions from deeply virtual Compton scattering and its interference with the Bethe-Heitler process in measurements on a hydrogen target

Author

Airapetian, A., Akopov, N., Akopov, Z., Aschenauer, E. C., Augustyniak, W., Avakian, R., Avetissian, A., Avetisyan, E., Bacchetta, A., Belostotski, S., Bianchi, N., Blok, H. P., Borissov, A., Bowles, J., Brodski, I., Bryzgalov, V., Burns, J., Capiluppi, Marco, Capitani, G. P., Cisbani, E., Ciullo, Giuseppe, Contalbrigo, Marco, Ferretti, Paola, Deconinck, W., De Leo, R., De Nardo, L., De Sanctis, E., Diefenthaler, M., Di Nezza, P., Dueren, M., Ehrenfried, M., Elbakian, G., Ellinghaus, F., Elschenbroich, U., Fabbri, R., Fantoni, A., Felawka, L., Frullani, S., Gabbert, D., Gapienko, G., Gapienko, V., Garibaldi, F., Gharibyan, V., Giordano, Francesca, Gliske, S., Golembiovskaya, M., Hadjidakis, C., Hartig, M., Hasch, D., Hill, G., Hillenbrand, A., Hoek, M., Holler, Y., Hristova, I., Imazu, Y., Ivanilov, A., Izotov, A., Jackson, H. E., H. S., Jo, Joosten, S., Kaiser, R., Karyan, G., Keri, T., Kinney, E., Kisselev, A., Kobayashi, N., Korotkov, V., Kozlov, V., Kravchenko, P., Lagamba, L., Lamb, R., Lapikas, L., Lehmann, I., Lenisa, Paolo, Linden Levy, L. A., Lopez Ruiz, A., Lorenzon, W., X. G., Lu, X. R., Lu, B. Q., Ma, Mahon, D., Makins, N. C. R., Manaenkov, S. I., Manfre, L., Mao, Y., Marianski, B., Martinez de la Ossa, A., Marukyan, H., Miller, C. A., Miyachi, Y., Movsisyan, A., Murray, M., Mussgiller, A., Nappi, E., Naryshkin, Y., Nass, A., Negodaev, M., Nowak, W. D., Pappalardo, Luciano Libero, Perez Benito, R., Pickert, N., Raithel, M., Reimer, P. E., Reolon, A. R., Riedl, C., Rith, K., Rosner, G., Rostomyan, A., Rubin, J., Ryckbosch, D., Salomatin, Y., Sanftl, F., Schaefer, A., Schnell, G., Seitz, B., Shibata, T. A., Shutov, V., Stancari, Michelle Dawn, Statera, Marco, Steffens, E., Steijger, J. J. M., Stenzel, H., Stewart, J., Stinzing, F., Taroian, S., Terkulov, A., Trzcinski, A., Tytgat, M., van der Nat, P. B., Van Haarlem, Y., Van Hulse, C., Veretennikov, D., Vikhrov, V., Vilardi, I., Vogel, C., Wang, S., Yaschenko, S., Ye, H., Ye, Z., Yen, S., Yu, W., Zeiler, D., Zihlmann, B., Zupranski, P., and Biophotonics and Medical Imaging

Subjects
Nuclear and High Energy Physics, Particle physics, Photon, Proton, 12.39.-x Phenomenological quark models, FOS: Physical sciences, Parton, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Cross section (physics), Lepton-nucleon scattering, 0103 physical sciences, time reversal and other discrete symmetries, ddc:530, 010306 general physics, 11.30.Er Charge conjugation, Physics, Luminosity (scattering theory), 010308 nuclear & particles physics, Compton scattering, Helicity, 13.60.Fz Elastic and Compton scattering, parity, 11.30.Er Charge conjugation, parity, time reversal and other discrete symmetries, 13.60.Hb Total and inclusive cross sections (including deep-inelastic processes), Beam (structure)
Abstract

Hard exclusive leptoproduction of real photons from an unpolarized proton target is studied in an effort to elucidate generalized parton distributions. The data accumulated during the years 1996--2005 with the HERMES spectrometer are analyzed to yield asymmetries with respect to the combined dependence of the cross section on beam helicity and charge, thereby revealing previously unseparated contributions from deeply virtual Compton scattering and its interference with the Bethe--Heitler process. The integrated luminosity is sufficient to show correlated dependences on two kinematic variables, and provides the most precise determination of the dependence on only the beam charge., 21 pages, 5 Figures, and 5 Tables

Published
2009
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42. Observation of the Naive-T-odd Sivers Effect in Deep-Inelastic Scattering

Author

P. Lenisa, A. Trzcinski, P. E. Reimer, C. A. Miller, E. De Sanctis, V. Gharibyan, Franco Garibaldi, A. López Ruiz, E. Avetisyan, V. A. Korotkov, Alessandra Fantoni, M. Hoek, M. Contalbrigo, Y. Van Haarlem, L. Lagamba, Z. Akopov, G. Elbakian, D. Gabbert, Y. Salomatin, K. P. Schüler, S. I. Manaenkov, B. Q. Ma, B. Ball, C. B. Van Hulse, Frank Ellinghaus, A. Nass, E. R. Kinney, R. De Leo, H. S. Jo, B. Zihlmann, Shan Wang, Nicola Bianchi, Y. Naryshkin, R. Perez-Benito, E. Cisbani, Alexander Borissov, A. Ivanilov, W. Yu, Xianguo Lu, M. Negodaev, H. Böttcher, J. G. Rubin, M. Ehrenfried, F. Sanftl, Hasko Stenzel, S. Yen, M. Capiluppi, I. Lehmann, W. Augustyniak, J. Stewart, M. Statera, Ralf Kaiser, Andreas Mussgiller, V. A. Gapienko, A. Hillenbrand, Y. Imazu, C. Riedl, S. Yaschenko, Hengqiang Ye, M. Stancari, P. Zupranski, G. Ciullo, D. Zeiler, A. Rostomyan, A. R. Reolon, A. Avetissian, V. Bryzgalov, C. Vogel, H. E. Jackson, A. Movsisyan, N. C. R. Makins, B. Seitz, G. Gapienko, Y. Holler, Stephen V. Gliske, T. A. Shibata, Wouter Deconinck, U. Elschenbroich, Adel Terkulov, Michael Tytgat, J. J. M. Steijger, Michael Düren, P. B. van der Nat, Dirk Ryckbosch, G. Rosner, Vitaly Shutov, H. P. Blok, X. R. Lu, L. Felawka, Wolfgang Lorenzon, S. Taroian, Ivana Hristova, G. Hill, G. P. Capitani, D. Veretennikov, Salvatore Frullani, M. Hartig, P. F. Dalpiaz, R. Lamb, P. Di Nezza, F. Giordano, J. Burns, N. Akopov, K. Rith, A. Airapetian, Y. J. Mao, P. Kravchenko, M. Diefenthaler, J. Dreschler, L. De Nardo, Zhenyu Ye, E. C. Aschenauer, F. Stinzing, David Mahon, Andreas Schäfer, H. Marukyan, L. A. Linden-Levy, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, G. Schnell, W.-D. Nowak, L. Manfré, A. Martinez de la Ossa, L. Lapikás, Eugenio Nappi, C. Bonomo, M. Varanda, T. Keri, V. Vikhrov, Morgan Murray, I. Vilardi, B. Marianski, Arne Vandenbroucke, Riccardo Fabbri, Alessandro Bacchetta, S. Joosten, A. Kisselev, V. Kozlov, Luciano Pappalardo, (Astro)-Particles Physics, Network Institute, Student Lab and Education, and Artificial Intelligence (section level)

Subjects
Particle physics, Meson, Polarized hydrogen target, Hadron, General Physics and Astronomy, FOS: Physical sciences, Elementary particle, Parton, Inelastic scattering, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Transverse momentum dependents, High Energy Physics - Experiment (hep-ex), Pion, 0103 physical sciences, ddc:550, 010306 general physics, Nuclear Experiment, Physics, Cross section, 010308 nuclear & particles physics, Scattering, Deep inelastic scattering, Parton distribution functions, Single-spin asymmetries, Hydrogen, Distribution functions, High Energy Physics::Experiment
Abstract

Azimuthal single-spin asymmetries of lepto-produced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for a naive-T-odd, transverse-momentum-dependent parton distribution function is deduced from non-vanishing Sivers effects for pi+, pi0, and K+, K-, as well as in the difference of the pi+ and pi- cross sections., Comment: 6 pages, 4 figures

Published
2009
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43. Nuclear-mass dependence of azimuthal beam-helicity and beam-charge asymmetries in deeply virtual Compton scattering

Author

Y. Holler, D. Veretennikov, Xianguo Lu, M. Negodaev, F. Giordano, Y. Salomatin, P. E. Reimer, M. Contalbrigo, Alessandra Fantoni, Hengqiang Ye, M. Hoek, Rezo Shanidze, Martin Raithel, E. C. Aschenauer, J. Burns, B. Zihlmann, Michael Tytgat, A. Nass, B. Q. Ma, M. Hartig, P. Lenisa, K. Rith, V. A. Korotkov, S. Taroian, Alexander Borissov, B. Ball, C. B. Van Hulse, M. Capiluppi, H. S. Jo, M. Ehrenfried, T. Keri, Salvatore Frullani, M. Statera, A. Airapetian, R. De Leo, A. Ivanilov, P. F. Dalpiaz, Stephen V. Gliske, Shan Wang, V. A. Gapienko, E. Avetisyan, P. Di Nezza, A. Trzcinski, M. Diefenthaler, Valeria Muccifora, C. A. Miller, C. Riedl, G. Elbakian, S. I. Manaenkov, H. Marukyan, N. Akopov, L. Felawka, M. Amarian, S. Yaschenko, S. Haan, G. Hill, S. Joosten, V. Vikhrov, J. G. Rubin, F. Stinzing, X. R. Lu, A. López Ruiz, G. Karyan, I. Lehmann, N. C. R. Makins, G. P. Capitani, W. Yu, A. Kisselev, W. Augustyniak, V. Kozlov, Wouter Deconinck, Ralf Kaiser, Y. Van Haarlem, S. Belostotski, R. Lamb, V. Bryzgalov, Dirk Ryckbosch, M. Stancari, L. Lagamba, Adel Terkulov, A. Rostomyan, A. R. Reolon, G. Ciullo, A. Avetissian, E. Steffens, Luciano Pappalardo, Z. Akopov, T. A. Shibata, P. Zupranski, I. Vilardi, G. Gavrilov, H. Böttcher, R.O. Avakian, G. Gapienko, D. Zeiler, R. Perez-Benito, H. E. Jackson, E. Cisbani, Vadim Guzey, B. Marianski, D. Gabbert, Morgan Murray, K. P. Schüler, Andreas Mussgiller, E. De Sanctis, J. Stewart, Frank Ellinghaus, G. Rosner, Franco Garibaldi, Vitaly Shutov, H. P. Blok, A. Movsisyan, E. R. Kinney, Nicola Bianchi, Wolfgang Lorenzon, Y. Naryshkin, Arne Vandenbroucke, Riccardo Fabbri, A. Hillenbrand, Y. Imazu, Ivana Hristova, J. Bowles, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, L. De Nardo, Zhenyu Ye, V. Gharibyan, J. J. M. Steijger, Michael Düren, W.-D. Nowak, L. Manfré, A. Martinez de la Ossa, H. Guler, Eugenio Nappi, G. Schnell, L. Lapikás, M. Varanda, David Mahon, Andreas Schäfer, Y. J. Mao, and P. Kravchenko

Subjects
Nuclear and High Energy Physics, Particle physics, Photon, Nuclear Theory, HERA, FOS: Physical sciences, IMPACT PARAMETER SPACE, Parton, GENERALIZED PARTON DISTRIBUTIONS, SPIN, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, ddc:530, Nuclear Experiment, 010306 general physics, Physics, Elastic scattering, 010308 nuclear & particles physics, Scattering, Compton scattering, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon, Beam (structure)
Abstract

The nuclear-mass dependence of azimuthal cross section asymmetries with respect to charge and longitudinal polarization of the lepton beam is studiedfor hard exclusive electroproduction of real photons. The observed beam-charge and beam-helicity asymmetries are attributed to the interference between the Bethe-Heitler and deeply virtual Compton scattering processes. For various nuclei, the asymmetries are extracted for both coherent and incoherent-enriched regions, which involve different (combinations of) generalized parton distributions. For both regions, the asymmetries are compared to those for a free proton, and no nuclear-mass dependence is found., Comment: 11 pages, 9 figures, 4 tables, minor revisions of text

Published
2009
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44. catena-Poly[[diaqua(3-cyanobenzoato-O,O')erbium]-bis-μ-(3-cyanobenzoato-O:O')]

Author

Chun-Hua Yan, Z.-M. Wang, Song Gao, G.-X. Xu, Tao Yi, and B.-Q. Ma

Subjects
chemistry.chemical_compound, Crystallography, Chain structure, Nitrile, Chemistry, Stereochemistry, Atom, Molecule, Chelation, General Medicine, Carboxylate, Crystal structure, General Biochemistry, Genetics and Molecular Biology
Abstract

The title compound, [Er(C 8 H 4 NO 2 ) 3 (H 2 O) 2 ] n , has a one-dimensional chain structure bridged by carboxylate groups. The Er III atom and one 3-cyanobenzoate ligand lie on a twofold axis and this ligand has its cyano group disordered over two sites. Each Er III atom is surrounded by two O atoms from one chelating carboxylate group, four O atoms from four different bridging carboxylate groups and two water molecules, leading to a square-antiprism coordination polyhedron.

Published
1999
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45. Measurement of Azimuthal Asymmetries With Respect To Both Beam Charge and Transverse Target Polarization in Exclusive Electroproduction of Real Photons

Author

HERMES collaboration, A Airapetian, N Akopov, Z Akopov, A Andrus, E.C Aschenauer, W Augustyniak, R Avakian, A Avetissian, E Avetisyan, L Barion, S Belostotski, N Bianchi, H.P Blok, H Böttcher, C Bonomo, A Borissov, A Brüll, V Bryzgalov, J Burns, M Capiluppi, G.P Capitani, E Cisbani, G Ciullo, M Contalbrigo, P.F Dalpiaz, W Deconinck, R. De Leo, M Demey, L. De Nardo, E. De Sanctis, M Diefenthaler, P. Di Nezza, J Dreschler, M Düren, M Ehrenfried, G Elbakian, F Ellinghaus, U Elschenbroich, R Fabbri, A Fantoni, L Felawka, S Frullani, A Funel, D Gabbert, G Gapienko, V Gapienko, F Garibaldi, G Gavrilov, V Gharibyan, F Giordano, S Gliske, H Guler, C Hadjidakis, D Hasch, T Hasegawa, G Hill, A Hillenbrand, M Hoek, Y Holler, I Hristova, G Iarygin, Y Imazu, A Ivanilov, A Izotov, H.E Jackson, A Jgoun, S Joosten, R Kaiser, T Keri, E Kinney, A Kisselev, M Kopytin, V Korotkov, V Kozlov, P Kravchenko, V.G Krivokhijine, L Lagamba, R Lamb, L Lapikás, I Lehmann, P Lenisa, L.A Linden-Levy, W Lorenzon, S Lu, X Lu, B.-Q Ma, D Mahon, B Maiheu, N.C.R Makins, Y Mao, B Marianski, H Marukyan, C.A Miller, Y Miyachi, V Muccifora, M Murray, A Mussgiller, A Nagaitsev, E Nappi, Y Naryshkin, A Nass, M Negodaev, W.-D Nowak, A Osborne, L.L Pappalardo, R Perez-Benito, N Pickert, M Raithel, P.E Reimer, A Reischl, A.R Reolon, C Riedl, K Rith, S.E Rock, G Rosner, A Rostomyan, L Rubacek, J Rubin, A.L Ruiz, D Ryckbosch, Y Salomatin, I Sanjiev, A Schäfer, G Schnell, K.P Schüler, B Seitz, C Shearer, T.-A Shibata, V Shutov, M Stancari, M Statera, E Steffens, J.J.M Steijger, H Stenzel, J Stewart, F Stinzing, P Tait, S Taroian, A Terkulov, A Trzcinski, M Tytgat, A Vandenbroucke, P.B. van der Nat, G. van der Steenhoven, Y. Van Haarlem, C. Van Hulse, M Varanda, D Veretennikov, V Vikhrov, I Vilardi, C Vogel, S Wang, S Yaschenko, H Ye, Z Ye, S Yen, W Yu, D Zeiler, B Zihlmann, P Zupranski, (Astro)-Particles Physics, and Student Lab and Education

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Photon, 010308 nuclear & particles physics, media_common.quotation_subject, Lepton-Nucleon Scattering, Compton scattering, FOS: Physical sciences, Parton, Polarization (waves), 01 natural sciences, Asymmetry, NO, High Energy Physics - Experiment, Transverse plane, High Energy Physics - Experiment (hep-ex), 0103 physical sciences, ddc:530, High Energy Physics::Experiment, 010306 general physics, Nucleon, Nuclear Experiment, media_common
Abstract

Azimuthal asymmetries in exclusive electroproduction of real photons are measured for the first time with respect to transverse target polarisation, providing new constraints on Generalized Parton Distributions. From the same data set on a hydrogen target, new results for the beam-charge asymmetry are also extracted with better precision than those previously reported. By comparing model calculations with measured asymmetries attributed to the interference between the deeply virtual Compton scattering and Bethe-Heitler processes, a model-dependent constraint is obtained on the total angular momenta carried by up and down quarks in the nucleon., 24 pages, 10 figures, 2 tables; 1 figure,3 references added, slight text change

Published
2008
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46. Precise determination of the spin structure function g(1) of the proton, deuteron, and neutron

Author

L. A. Linden-Levy, W.-D. Nowak, V. A. Gapienko, P. Zupranski, J. Streit, L. Felawka, I.A. Savin, N. Meyners, G. Rosner, W. Augustyniak, Shan Wang, G. P. Capitani, H. Böttcher, Andreas Schäfer, N. Bianchi, L. Rubacek, L. Lapikás, D. Veretennikov, G. Schnell, A. Funel, A. Nagaitsev, G. van der Steenhoven, A. Osborne, Salvatore Frullani, U. Stosslein, H. Ohsuga, Arne Vandenbroucke, L. Lagamba, Z. Akopov, Riccardo Fabbri, J. G. Rubin, P. F. Dalpiaz, Y. Naryshkin, Hidekazu Tanaka, G. Iarygin, P. Tait, Morgan Murray, T. A. Shibata, R.O. Avakian, Tetsuya Hasegawa, F. Giordano, A. Rostomyan, A. R. Reolon, Tsutomu Kobayashi, Y. Salomatin, M. Contalbrigo, A. Avetissian, P. Lenisa, A. Trzcinski, H. E. Jackson, H. Marukyan, N. Akopov, V. G. Krivokhijine, A. Airapetian, H. P. Blok, Y. X. Ye, M. Statera, A. Brull, B. Marianski, Martin Raithel, E. Devitsin, Wolfgang Lorenzon, E. C. Aschenauer, V. Shutov, A. Kisselev, B. Q. Ma, K. Garrow, Ivana Hristova, Hasko Stenzel, M. Capiluppi, C. Vogel, B. Hommez, C. Weiskopf, Alessandra Fantoni, M. Hoek, I. Sanjiev, G. Gapienko, F. Stinzing, J. Stewart, V. A. Kozlov, D. Reggiani, M. Ehrenfried, K. Rith, R. De Leo, P. E. Reimer, V. A. Korotkov, Michael Tytgat, Naomi C R Makins, R. Perez-Benito, B. Tchuiko, M. Kopytin, B. Maiheu, J. Dreschler, V. Vikhrov, M. Hartig, M. Demey, O. Grebeniouk, M. Stancari, Wouter Deconinck, P. Di Nezza, S. Taroian, P. Liebing, J. Lu, I. M. Gregor, Andrey V. Izotov, A. Jgoun, S. Yen, C. Shearer, B. Seitz, A. Borissov, Valeria Muccifora, C. Riedl, Ralf Kaiser, U. Elschenbroich, W.H.A. Hesselink, Y. Van Haarlem, M. Diefenthaler, E. Steffens, J. Seele, P. B. van der Nat, K. P. Schüler, E. De Sanctis, T. Michler, G. Elbakian, Franco Garibaldi, A. Hillenbrand, G. Gavrilov, H. Guler, A. Borysenko, A. Gute, A. Andrus, Eugenio Nappi, V. Mexner, E. Avetissian, N. Pickert, O. Mikloukho, Dirk Ryckbosch, M. Negodaev, S. Lu, Adel Terkulov, C. A. Miller, Y. Gärber, D. Gabbert, Y. J. Mao, P. Kravchenko, F. Masoli, T. Keri, J. J. M. Steijger, Michael Düren, A. Elalaoui-Moulay, Frank Ellinghaus, B. Zihlmann, E. R. Kinney, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, S. Belostotski, V. Bryzgalov, K. Sinram, L. De Nardo, Zhenyu Ye, V. Gharibyan, A. Reischl, B. Krauss, G. Ciullo, Y. Holler, A. Ivanilov, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Physics, HERMES experiment, Nuclear and High Energy Physics, Proton, FOS: Physical sciences, 14.20.Dh, 13.88.+e, 13.60.Hb, 13.60.−r, HERA, Inelastic scattering, High Energy Physics - Experiment, NO, Nuclear physics, High Energy Physics - Experiment (hep-ex), Deuterium, High Energy Physics::Experiment, Neutron, ddc:530, Atomic physics, Nuclear Experiment, Nucleon, Spin-½
Abstract

Precise measurements of the spin structure functions of the proton $g_1^p(x,Q^2)$ and deuteron $g_1^d(x,Q^2)$ are presented over the kinematic range $0.0041 \leq x \leq 0.9$ and $0.18 $ GeV$^2$ $\leq Q^2 \leq 20$ GeV$^2$. The data were collected at the HERMES experiment at DESY, in deep-inelastic scattering of 27.6 GeV longitudinally polarized positrons off longitudinally polarized hydrogen and deuterium gas targets internal to the HERA storage ring. The neutron spin structure function $g_1^n$ is extracted by combining proton and deuteron data. The integrals of $g_1^{p,d}$ at $Q^2=5$ GeV$^2$ are evaluated over the measured $x$ range. Neglecting any possible contribution to the $g_1^d$ integral from the region $x \leq 0.021$, a value of $0.330 \pm 0.011\mathrm{(theo.)}\pm0.025\mathrm{(exp.)}\pm 0.028$(evol.) is obtained for the flavor-singlet axial charge $a_0$ in a leading-twist NNLO analysis.

Published
2007
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47. Beam-spin asymmetries in the azimuthal distribution of pion electroproduction

Author

V. A. Korotkov, Wouter Deconinck, V. Mexner, J. Lu, S. Yen, B. Zihlmann, G. Elbakian, Y. Miyachi, H. Guler, Ralf Kaiser, B. Hommez, A. Nagaitsev, A. Borissov, M. Demey, G. Iarygin, H. Marukyan, E. Steffens, Dirk Ryckbosch, Hasko Stenzel, A. Airapetian, P. Lenisa, I.A. Savin, I. M. Gregor, V. Kozlov, A. Brull, G. Gavrilov, J. G. Rubin, A. Andrus, A. Trzcinski, B. Marianski, K. Sinram, L. De Nardo, T. Keri, Tsutomu Kobayashi, Y. J. Mao, P. Kravchenko, O. Grebeniouk, A. Elalaoui-Moulay, Frank Ellinghaus, E. R. Kinney, S. Lu, Y. Naryshkin, M. Negodaev, G.P. Capitani, M. Statera, S. Frullani, F. Stinzing, H. E. Jackson, V. G. Krivokhijine, Andreas Schäfer, N. Pickert, L. Felawka, M. Amarian, H. P. Blok, A. R. Reolon, T. A. Shibata, Adel Terkulov, C. Vogel, A. Funel, W.H.A. Hesselink, V. Muccifora, V. Vikhrov, J. J. M. Steijger, Michael Düren, Michael Tytgat, Y. Salomatin, Wolfgang Lorenzon, M. Stancari, P. E. Reimer, L. Lagamba, P. Di Nezza, P. Bailey, G. van der Steenhoven, C. A. Miller, Arne Vandenbroucke, P. Zupranski, Morgan Murray, R.O. Avakian, L. Rubacek, Riccardo Fabbri, B. Krauss, S. Taroian, K. P. Schüler, A. Fantoni, Ivana Hristova, H. Avakian, P.F. Dalpiaz, B. Q. Ma, A. Borysenko, F. Giordano, Alessandro Bacchetta, W. Augustyniak, M. Contalbrigo, E. Devitsin, O. Mikloukho, M. Ehrenfried, N. Meyners, Martin Raithel, W.-D. Nowak, R. De Leo, J. Stewart, K. Garrow, G. Rosner, E. C. Aschenauer, A. Kisselev, V. Shutov, A. Osborne, R. Seidl, E. Avetisyan, E. De Sanctis, T. Michler, Klaus Rith, V. Gharibyan, K. Oganessyan, I. Sanjiev, H. Böttcher, Naomi C R Makins, J. Streit, F. Masoli, S. Belostotski, D. Reggiani, M. Hartig, V. Bryzgalov, F. Garibaldi, C. Hadjidakis, P. Tait, J. Dreschler, M. Capiluppi, P. Liebing, Andrey V. Izotov, Z. Akopov, D. Hasch, Z. Ye, Hidekazu Tanaka, A. Jgoun, Y. Van Haarlem, C. Riedl, G. Gapienko, Shan Wang, H. Ohsuga, A. Rostomyan, A. Avetissian, K. Hafidi, M. Diefenthaler, J. Seele, A. Hillenbrand, A. Ivanilov, A. Reischl, Y. Holler, G. Ciullo, Tetsuya Hasegawa, V. A. Gapienko, N. Bianchi, R. Perez-Benito, B. Maiheu, C. Shearer, B. Seitz, E. Nappi, U. Elschenbroich, L. Lapikás, P. B. van der Nat, Y. X. Ye, L. A. Linden-Levy, M. Hoek, G. Schnell, B. Tchuiko, M. Kopytin, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Nuclear and High Energy Physics, Meson, Hadron, FOS: Physical sciences, Virtual particle, Inelastic scattering, 01 natural sciences, 7. Clean energy, 24.85.+p, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, 13.88.+e, 0103 physical sciences, ddc:530, SDG 7 - Affordable and Clean Energy, 010306 general physics, Nuclear Experiment, 13.60.-r, Physics, 010308 nuclear & particles physics, 13.87.Fh, 14.20.Dh, HERA, Science General, Scattering amplitude, Physics::Accelerator Physics, High Energy Physics::Experiment, Dimensionless quantity
Abstract

A measurement of the beam-spin asymmetry in the azimuthal distribution of pions produced in semi-inclusive deep-inelastic scattering off protons is presented. The measurement was performed using the HERMES spectrometer with a hydrogen gas target and the longitudinally polarized 27.6 GeV positron beam of HERA. The sinusoidal amplitude of the dependence of the asymmetry on the angle ϕ of the hadron production plane around the virtual photon direction relative to the lepton scattering plane was measured for π + π + , π − π − and π 0 π 0 mesons. The dependence of this amplitude on the Bjorken scaling variable and on the pion fractional energy and transverse momentum is presented. The results are compared to theoretical model calculations.

Published
2007
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48. Beam-charge azimuthal asymmetry and deeply virtual Compton scattering

Author

A. Airapetian, A. Reischl, L. Lagamba, C. Shearer, B. Seitz, Z. Akopov, Shan Wang, H. Ohsuga, Klaus Rith, U. Elschenbroich, F. Stinzing, P. B. van der Nat, H. Y. Lu, A. Borissov, V. A. Gapienko, A. Nagaitsev, S. Frullani, G. Ciullo, M. Demey, C. A. Miller, N. Pickert, Dirk Ryckbosch, A. Rostomyan, A. R. Reolon, A. Avetissian, P. F. Dalpiaz, V. A. Korotkov, G. Iarygin, I. M. Gregor, R. Seidl, Hidekazu Tanaka, M. Stancari, M. Beckmann, A. Elalaoui-Moulay, Frank Ellinghaus, W.-D. Nowak, E. R. Kinney, M. Statera, A. Laziev, P. E. Reimer, K. Garrow, N. Akopov, L. Rubacek, Andrey V. Izotov, M. Bouwhuis, H. Böttcher, V. A. Kozlov, J. Seele, Valeria Muccifora, H. Marukyan, A. Osborne, Y. Naryshkin, Y. X. Ye, G. Gapienko, A. Hillenbrand, G. Elbakian, J. Volmer, Alessandra Fantoni, A. Funel, M. Hoek, A. Ivanilov, J. Stewart, K. P. Schüler, P. Zupranski, Y. J. Mao, P. Tait, B. Maiheu, A. Brull, B. Tchuiko, M. Kopytin, M. Contalbrigo, Tsutomu Kobayashi, L. Felawka, M. Amarian, W. Augustyniak, A. Andrus, Martin Raithel, Eugenio Nappi, E. De Sanctis, T. Michler, Y. Salomatin, S. Lu, E. C. Aschenauer, J. J. M. Steijger, M. Negodaev, Michael Düren, G. van der Steenhoven, V. Shutov, B. Krauss, G. P. Capitani, Adel Terkulov, I. Sanjiev, F. Masoli, Naomi C R Makins, Michael Tytgat, E. Avetissian, D. Balin, Nicola Bianchi, O. Mikloukho, W.H.A. Hesselink, G. Schnell, T. Chen, D. Gaskell, A. Jgoun, B. Q. Ma, H. E. Jackson, M. Hartig, N. Meyners, G. Rosner, L. A. Linden-Levy, K. Oganessyan, Y. Holler, S. Taroian, A. Borysenko, V. G. Krivokhijine, M. Ehrenfried, B. Marianski, J. Lu, C. Vogel, S. Yen, P. Lenisa, R. De Leo, Rezo Shanidze, A. Trzcinski, Ralf Kaiser, S. Belostotski, V. Bryzgalov, Wouter Deconinck, P. Di Nezza, F. Garibaldi, P. Liebing, E. Steffens, J. Dreschler, G. Gavrilov, V. Vikhrov, K. Sinram, L. De Nardo, Zhenyu Ye, Manuella Vincter, Hasko Stenzel, M. Capiluppi, L. Lapikás, I.A. Savin, J. G. Rubin, V. Gharibyan, V. Mexner, K. Hafidi, Morgan Murray, Y. Van Haarlem, B. Zihlmann, P. Bailey, T. A. Shibata, Cynthia Marie Hadjidakis, Y. Miyachi, R.O. Avakian, Andreas Schäfer, J. Wendland, W. Sommer, D. Hasch, D. H. Potterveld, E. Devitsin, A. Kisselev, Arne Vandenbroucke, Riccardo Fabbri, D. Reggiani, O. Grebeniouk, C. Riedl, H. P. Blok, Wolfgang Lorenzon, Ivana Hristova, B. Hommez, (Astro)-Particles Physics, and Photo Conversion Materials

Subjects
HERMES experiment, Elastic scattering, Physics, Nuclear and High Energy Physics, Particle physics, Photon, Scattering, media_common.quotation_subject, High Energy Physics::Phenomenology, Compton scattering, FOS: Physical sciences, DESY, HERA, 13.60.Fz Elastic and Compton scattering, 14.20.Dh, 24.85.+p, Asymmetry, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), ddc:530, High Energy Physics::Experiment, Nuclear Experiment, media_common
Abstract

The first observation of an azimuthal cross section asymmetry with respect to the charge of the incoming lepton beam is reported from a study of hard exclusive electroproduction of real photons. The data have been accumulated by the HERMES experiment at DESY, in which the HERA 27.6 GeV electron or positron beam scattered off an unpolarized hydrogen gas target. The observed asymmetry is attributed to the interference between the Bethe-Heitler process and the deeply virtual Compton scattering (DVCS) process. The interference term is sensitive to DVCS amplitudes, which provide the most direct access to generalized parton distributions. © 2007 The American Physical Society.

Published
2007
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49. Double-hadron leptoproduction in the nuclear medium

Author

V. A. Korotkov, Klaus Rith, M. Stancari, J. Stewart, J. J. M. Steijger, A. Brüll, Michael Düren, G. Elbakian, D. Veretennikov, A. Airapetian, B. Zihlmann, K. Sinram, L. De Nardo, Zhenyu Ye, V. Gharibyan, W. Augustyniak, Cynthia Marie Hadjidakis, Y. Miyachi, D. Hasch, A. Funel, F. Giordano, P. Di Nezza, G. van der Steenhoven, M. Demey, Shan Wang, H. Ohsuga, A. Osborne, P. Liebing, R. Seidl, F. Stinzing, Hasko Stenzel, V. A. Gapienko, I. M. Gregor, G. Iarygin, M. Capiluppi, P. Lenisa, L. A. Linden-Levy, H. Böttcher, Michael Tytgat, A. Trzcinski, W.H.A. Hesselink, W.-D. Nowak, Tsutomu Kobayashi, A. Borysenko, H. Marukyan, J. G. Rubin, A. Rostomyan, A. Avetissian, S. Taroian, L. Lapikás, Dirk Ryckbosch, B. Hommez, Frank Ellinghaus, J. Streit, S. Lu, Adel Terkulov, G. Gapienko, I.A. Savin, E. R. Kinney, O. Grebeniouk, C. Riedl, C. Vogel, Salvatore Frullani, P. Tait, P. Bailey, L. Lagamba, H. Guler, Z. Akopov, Y. Naryshkin, P. F. Dalpiaz, Eugenio Nappi, A. Borissov, V. Vikhrov, A. R. Roelon, J. Dreschler, Hidekazu Tanaka, R. Perez-Benito, B. Maiheu, A. Andrus, H. E. Jackson, Andreas Schäfer, H. P. Blok, M. Negodaev, Morgan Murray, A. Jgoun, B. Krauss, Y. Van Haarlem, B. Marianski, Wolfgang Lorenzon, Tetsuya Hasegawa, Valeria Muccifora, Ivana Hristova, Y. Salomatin, K. P. Schüler, S. Belostotski, P. Zupranski, B. Q. Ma, V. Bryzgalov, M. Ehrenfried, R. De Leo, E. Avetissian, Nicola Bianchi, O. Mikloukho, Arne Vandenbroucke, N. Meyners, G. Rosner, Riccardo Fabbri, I. Sanjiev, K. Garrow, V. A. Kozlov, L. Felawka, M. Amarian, A. Nagaitsev, G. P. Capitani, G. Schnell, N. Akopov, Y. J. Mao, P. Kravchenko, V. G. Krivokhijine, F. Masoli, P. E. Reimer, M. Contalbrigo, Y. X. Ye, Martin Raithel, E. C. Aschenauer, V. Shutov, C. Shearer, B. Seitz, Naomi C R Makins, U. Elschenbroich, T. Keri, P. B. van der Nat, M. Hartig, J. Lu, Alessandra Fantoni, Wouter Deconinck, S. Yen, M. Hoek, K. A. Griffioen, Ralf Kaiser, B. Tchuiko, M. Kopytin, E. Steffens, G. Gavrilov, V. Mexner, T. A. Shibata, R.O. Avakian, A. Ivanilov, A. Reischl, E. Devitsin, A. Kisselev, G. Ciullo, D. Reggiani, Y. Holler, E. De Sanctis, T. Michler, Franco Garibaldi, M. Diefenthaler, J. Seele, A. Hillenbrand, N. Pickert, C. A. Miller, A. Elalaoui-Moulay, M. Statera, Andrey V. Izotov, L. Rubacek, (Astro)-Particles Physics, Photo Conversion Materials, and Student Lab and Education

Subjects
Particle physics, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Inelastic scattering, 25.30.Rw, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Xenon, ddc:550, 13.60.−r, 13.87.Fh, 25.75.Gz, Nuclear Experiment, Physics, Scattering, High Energy Physics::Phenomenology, Krypton, HERA, Nuclear matter, Deep inelastic scattering, chemistry, Deuterium, High Energy Physics::Experiment
Abstract

Physical review letters 96, 162301 (2006). doi:10.1103/PhysRevLett.96.162301, Published by APS, College Park, Md.

Published
2006
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50. Longitudinal spin transfer to the Lambda hyperon in semiinclusive deep-inelastic scattering

Author

B. Hommez, B. Marianski, K. Sinram, L. De Nardo, A. Osborne, B. Krauss, Zhenyu Ye, Y. Van Haarlem, A. Borissov, V. Gharibyan, K. Hafidi, R. Seidl, P. E. Reimer, M. Bouwhuis, H. Böttcher, M. Diefenthaler, Morgan Murray, G. Iarygin, J. Seele, B. Zihlmann, V. Vikhrov, Manuella Vincter, A. Hillenbrand, Houbing Lu, P. Tait, J. Dreschler, A. Andrus, Cynthia Marie Hadjidakis, Y. Miyachi, J. Wendland, W. Sommer, M. Demey, M. Negodaev, D. Hasch, D. H. Potterveld, Dirk Ryckbosch, H. Marukyan, S. Belostotski, V. Bryzgalov, P. Bailey, I. M. Gregor, Y. Salomatin, Tsutomu Kobayashi, W. Augustyniak, M. Statera, Arne Vandenbroucke, Riccardo Fabbri, C. Vogel, B. Q. Ma, H. P. Blok, M. Beckmann, M. Ehrenfried, R. De Leo, Wolfgang Lorenzon, Andrey V. Izotov, Klaus Rith, J. J. M. Steijger, Michael Düren, T. A. Shibata, V. A. Korotkov, R.O. Avakian, A. Elalaoui-Moulay, Frank Ellinghaus, H. Ohsuga, Ivana Hristova, E. R. Kinney, M. Stancari, A. Jgoun, E. Devitsin, C. Riedl, Y. Naryshkin, Michael Tytgat, H. E. Jackson, A. Kisselev, V. G. Krivokhijine, A. Brüll, P. Lenisa, A. Trzcinski, N. Pickert, D. Reggiani, W.-D. Nowak, G. Elbakian, T. Chen, S. Taroian, C. A. Miller, Eugenio Nappi, S. I. Manaenkov, A. Nagaitsev, K. Oganessyan, A. Rostomyan, Salvatore Frullani, A. Funel, A. R. Reolon, A. Avetissian, G. van der Steenhoven, P. F. Dalpiaz, A. Borysenko, G. Gapienko, K. P. Schüler, I.A. Savin, Andreas Schäfer, E. De Sanctis, T. Michler, Franco Garibaldi, C. Shearer, B. Seitz, B. Maiheu, E. Avetissian, D. Balin, Nicola Bianchi, N. Akopov, O. Mikloukho, U. Elschenbroich, P. B. van der Nat, Y. J. Mao, P. Kravchenko, V. A. Gapienko, P. Di Nezza, P. Liebing, F. Masoli, J. G. Rubin, A. Laziev, H. C. Chiang, Song-Ming Wang, Y. X. Ye, Alessandra Fantoni, M. Hoek, B. Tchuiko, M. Kopytin, T. Keri, Wouter Deconinck, V. Mexner, Hidekazu Tanaka, K. Garrow, V. A. Kozlov, P. Zupranski, L. Lagamba, Z. Akopov, N. Meyners, J. Lu, G. Rosner, S. Yen, Ralf Kaiser, A. Airapetian, E. Steffens, F. Stinzing, G. Gavrilov, Xian Chen, J. Volmer, A. Ivanilov, L. Felawka, M. Amarian, X. R. Lu, M. Contalbrigo, G. P. Capitani, Martin Raithel, E. C. Aschenauer, G. Schnell, V. Shutov, I. Sanjiev, Naomi C R Makins, M. Hartig, A. Reischl, G. Ciullo, L. Rubacek, O. Grebeniouk, L. A. Linden-Levy, Y. Holler, L. Lapikás, J. Stewart, W.H.A. Hesselink, Valeria Muccifora, S. Lu, Adel Terkulov, Hasko Stenzel, M. Capiluppi, (Astro)-Particles Physics, and Photo Conversion Materials

Subjects
HERMES experiment, Nuclear and High Energy Physics, Particle physics, Lambda baryon, Lambda, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Positron, 13.88.+e, 0103 physical sciences, ddc:530, 13.60.−r, 13.60.Rj, SDG 7 - Affordable and Clean Energy, 010306 general physics, Physics, 010308 nuclear & particles physics, Scattering, Hyperon, HERA, Deep inelastic scattering, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract

The transfer of polarization from a high-energy positron to a {lambda}{sup 0} hyperon produced in semiinclusive deep-inelastic scattering has been measured. The data have been obtained by the HERMES experiment at DESY using the 27.6 GeV longitudinally polarized positron beam of the HERA collider and unpolarized gas targets internal to the positron (electron) storage ring. The longitudinal spin-transfer coefficient is found to be D{sub LL{sup '}}{sup {lambda}}=0.11{+-}0.10(stat){+-}0.03(syst) at an average fractional energy carried by the {lambda}{sup 0} hyperon =0.45. The dependence of D{sub LL{sup '}}{sup {lambda}} on both the fractional energy z and the fractional longitudinal momentum x{sub F} is presented.

Published
2006
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