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6,908 results on '"Lee H-S"'

1. COSINE-100U: Upgrading the COSINE-100 Experiment for Enhanced Sensitivity to Low-Mass Dark Matter Detection

Author

Lee, D. H., Cho, J. Y., Ha, C., Jeon, E. J., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Ko, Y. J., Lee, H., Lee, H. S., Lee, I. S., Lee, J., Lee, S. H., Lee, S. M., Maruyama, R. H., Park, J. C., Park, K. S., Park, K., Park, S. D., Seo, K. M., Son, M. K., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

An upgrade of the COSINE-100 experiment, COSINE-100U, has been prepared for installation at Yemilab, a new underground laboratory in Korea, following 6.4 years of operation at the Yangyang Underground Laboratory. The COSINE-100 experiment aimed to investigate the annual modulation signals reported by the DAMA/LIBRA but observed a null result, revealing a more than 3$\sigma$ discrepancy. COSINE-100U seeks to explore new parameter spaces for dark matter detection using NaI(Tl) detectors. All eight NaI(Tl) crystals, with a total mass of 99.1 kg, have been upgraded to improve light collection efficiency, significantly enhancing dark matter detection sensitivity. This paper describes the detector upgrades, performance improvements, and the enhanced sensitivity to low-mass dark matter detection in the COSINE-100U experiment., Comment: 14 pages, 17 figures

Published
2024

2. COSINE-100 Full Dataset Challenges the Annual Modulation Signal of DAMA/LIBRA

Author

Carlin, N., Cho, J. Y., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Luan, N. T., Machado, V. H. A., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, J. C., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Son, M. K., Spooner, N. J. C., Truc, L. T., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment
Abstract

For over 25 years, the DAMA/LIBRA collaboration has claimed to observe an annual modulation signal, suggesting the existence of dark matter interactions. However, no other experiments have replicated their result using different detector materials. To address this puzzle, the COSINE-100 collaboration conducted a model-independent test using 106 kg of sodium iodide as detectors, the same target material as DAMA/LIBRA. Analyzing data collected over 6.4 years, with improved energy calibration and time-dependent background description, we found no evidence of an annual modulation signal, challenging the DAMA/LIBRA result with a confidence level greater than 3$\sigma$. This finding represents a significant step toward resolving the long-standing debate surrounding DAMA/LIBRA's dark matter claim, indicating that the observed modulation is unlikely to be caused by dark matter interactions.

Published
2024

3. Lowering threshold of NaI(Tl) scintillator to 0.7 keV in the COSINE-100 experiment

Author

Yu, G. H., Carlin, N., Cho, J. Y., Choi, J. J., Choi, S., Ezeribe, A. C., França, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Luan, N. T., Machado, V. H. A., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, J. C., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Son, M. K., Spooner, N. J. C., Truc, L. T., and Yang, L.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

COSINE-100 is a direct dark matter search experiment, with the primary goal of testing the annual modulation signal observed by DAMA/LIBRA, using the same target material, NaI(Tl). In previous analyses, we achieved the same 1 keV energy threshold used in the DAMA/LIBRA's analysis that reported an annual modulation signal with 11.6$\sigma$ significance. In this article, we report an improved analysis that lowered the threshold to 0.7 keV, thanks to the application of Multi-Layer Perception network and a new likelihood parameter with waveforms in the frequency domain. The lower threshold would enable a better comparison of COSINE-100 with new DAMA results with a 0.75 keV threshold and account for differences in quenching factors. Furthermore the lower threshold can enhance COSINE-100's sensitivity to sub-GeV dark matter searches.

Published
2024

4. Improved background modeling for dark matter search with COSINE-100

Author

Yu, G. H., Carlin, N., Cho, J. Y., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Luan, N. T., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, J. C., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Son, M. K., Spooner, N. J. C., Truc, L. T., and Yang, L.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

COSINE-100 aims to conclusively test the claimed dark matter annual modulation signal detected by DAMA/LIBRA collaboration. DAMA/LIBRA has released updated analysis results by lowering the energy threshold to 0.75 keV through various upgrades. They have consistently claimed to have observed the annual modulation. In COSINE-100, it is crucial to lower the energy threshold for a direct comparison with DAMA/LIBRA, which also enhances the sensitivity of the search for low-mass dark matter, enabling COSINE-100 to explore this area. Therefore, it is essential to have a precise and quantitative understanding of the background spectrum across all energy ranges. This study expands the background modeling from 0.7 to 4000 keV using 2.82 years of COSINE-100 data. The modeling has been improved to describe the background spectrum across all energy ranges accurately. Assessments of the background spectrum are presented, considering the nonproportionality of NaI(Tl) crystals at both low and high energies and the characteristic X-rays produced by the interaction of external backgrounds with materials such as copper. Additionally, constraints on the fit parameters obtained from the alpha spectrum modeling fit are integrated into this model. These improvements are detailed in the paper.

Published
2024

5. First Direct Search for Light Dark Matter Using the NEON Experiment at a Nuclear Reactor

Author

Choi, J. J., Ha, C., Jeon, E. J., Kim, J. Y., Kim, K. W., Kim, S. H., Kim, S. K., Kim, Y. D., Ko, Y. J., Koh, B. C., Lee, S. H., Lee, I. S., Lee, H., Lee, H. S., Lee, J. S., Oh, Y. M., and Park, B. J.

Subjects
High Energy Physics - Experiment
Abstract

We report new results from the Neutrino Elastic Scattering Observation with NaI (NEON) experiment in the search for light dark matter (LDM) using 2,636 kg$\cdot$days of NaI(Tl) exposure. The experiment employs an array of NaI(Tl) crystals with a total mass of 16.7 kg, located 23.7 meters away from a 2.8 GW thermal power nuclear reactor. We investigated LDM produced by the $\textit{invisible decay}$ of dark photons generated by high-flux photons during reactor operation. The energy spectra collected during reactor-on and reactor-off periods were compared within the LDM signal region of $1-10$ keV. No signal consistent with LDM interaction with electrons was observed, allowing us to set 90% confidence level exclusion limits for the dark matter-electron scattering cross-section ($\sigma_e$) across dark matter masses ranging from 1 keV/c$^2$ to 1 MeV/c$^2$. Our results set a 90% confidence level upper limit of $\sigma_e = 3.17\times10^{-35}~\mathrm{cm^2}$ for a dark matter mass of 100 keV/c$^2$, marking the best laboratory result in this mass range. Additionally, our search extends the coverage of LDM below 100 keV/c$^2$ first time.

Published
2024

6. Development of MMC-based lithium molybdate cryogenic calorimeters for AMoRE-II

Author

Agrawal, A., Alenkov, V. V., Aryal, P., Bae, H., Beyer, J., Bhandari, B., Boiko, R. S., Boonin, K., Buzanov, O., Byeon, C. R., Chanthima, N., Cheoun, M. K., Choe, J. S., Choi, S., Choudhury, S., Chung, J. S., Danevich, F. A., Djamal, M., Drung, D., Enss, C., Fleischmann, A., Gangapshev, A. M., Gastaldo, L., Gavrilyuk, Y. M., Gezhaev, A. M., Gileva, O., Grigorieva, V. D., Gurentsov, V. I., Ha, C., Ha, D. H., Ha, E. J., Hwang, D. H., Jeon, E. J., Jeon, J. A., Jo, H. S., Kaewkhao, J., Kang, C. S., Kang, W. G., Kazalov, V. V., Kempf, S., Khan, A., Khan, S., Kim, D. Y., Kim, G. W., Kim, H. B., Kim, H. J., Kim, H. L., Kim, H. S., Kim, M. B., Kim, S. C., Kim, S. K., Kim, S. R., Kim, W. T., Kim, Y. D., Kim, Y. H., Kirdsiri, K., Ko, Y. J., Kobychev, V. V., Kornoukhov, V., Kuzminov, V. V., Kwon, D. H., Lee, C. H., Lee, D. Y., Lee, E. K., Lee, H. J., Lee, H. S., Lee, J., Lee, J. Y., Lee, K. B., Lee, M. H., Lee, M. K., Lee, S. W., Lee, Y. C., Leonard, D. S., Lim, H. S., Mailyan, B., Makarov, E. P., Nyanda, P., Oh, Y., Olsen, S. L., Panasenko, S. I., Park, H. K., Park, H. S., Park, K. S., Park, S. Y., Polischuk, O. G., Prihtiadi, H., Ra, S., Ratkevich, S. S., Rooh, G., Sari, M. B., Seo, J., Seo, K. M., Sharma, B., Shin, K. A., Shlegel, V. N., Siyeon, K., So, J., Sokur, N. V., Son, J. K., Song, J. W., Srisittipokakun, N., Tretyak, V. I., Wirawan, R., Woo, K. R., Yeon, H. J., Yoon, Y. S., and Yue, Q.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Nuclear Experiment
Abstract

The AMoRE collaboration searches for neutrinoless double beta decay of $^{100}$Mo using molybdate scintillating crystals via low temperature thermal calorimetric detection. The early phases of the experiment, AMoRE-pilot and AMoRE-I, have demonstrated competitive discovery potential. Presently, the AMoRE-II experiment, featuring a large detector array with about 90 kg of $^{100}$Mo isotope, is under construction.This paper discusses the baseline design and characterization of the lithium molybdate cryogenic calorimeters to be used in the AMoRE-II detector modules. The results from prototype setups that incorporate new housing structures and two different crystal masses (316 g and 517 - 521 g), operated at 10 mK temperature, show energy resolutions (FWHM) of 7.55 - 8.82 keV at the 2.615 MeV $^{208}$Tl $\gamma$ line, and effective light detection of 0.79 - 0.96 keV/MeV. The simultaneous heat and light detection enables clear separation of alpha particles with a discrimination power of 12.37 - 19.50 at the energy region around $^6$Li(n, $\alpha$)$^3$H with Q-value = 4.785 MeV. Promising detector performances were demonstrated at temperatures as high as 30 mK, which relaxes the temperature constraints for operating the large AMoRE-II array.

Published
2024

7. Improved limit on neutrinoless double beta decay of \mohundred~from AMoRE-I

Author

Agrawal, A., Alenkov, V. V., Aryal, P., Beyer, J., Bhandari, B., Boiko, R. S., Boonin, K., Buzanov, O., Byeon, C. R., Chanthima, N., Cheoun, M. K., Choe, J. S., Choi, Seonho, Choudhury, S., Chung, J. S., Danevich, F. A., Djamal, M., Drung, D., Enss, C., Fleischmann, A., Gangapshev, A. M., Gastaldo, L., Gavrilyuk, Y. M., Gezhaev, A. M., Gileva, O., Grigorieva, V. D., Gurentsov, V. I., Ha, C., Ha, D. H., Ha, E. J., Hwang, D. H., Jeon, E. J., Jeon, J. A., Jo, H. S., Kaewkhao, J., Kang, C. S., Kang, W. G., Kazalov, V. V., Kempf, S., Khan, A., Khan, S., Kim, D. Y., Kim, G. W., Kim, H. B., Kim, Ho-Jong, Kim, H. J., Kim, H. L., Kim, H. S., Kim, M. B., Kim, S. C., Kim, S. K., Kim, S. R., Kim, W. T., Kim, Y. D., Kim, Y. H., Kirdsiri, K., Ko, Y. J., Kobychev, V. V., Kornoukhov, V., Kuzminov, V. V., Kwon, D. H., Lee, C. H., Lee, DongYeup, Lee, E. K., Lee, H. J., Lee, H. S., Lee, J., Lee, J. Y., Lee, K. B., Lee, M. H., Lee, M. K., Lee, S. W., Lee, Y. C., Leonard, D. S., Lim, H. S., Mailyan, B., Makarov, E. P., Nyanda, P., Oh, Y., Olsen, S. L., Panasenko, S. I., Park, H. K., Park, H. S., Park, K. S., Park, S. Y., Polischuk, O. G., Prihtiadi, H., Ra, S., Ratkevich, S. S., Rooh, G., Sari, M. B., Seo, J., Seo, K. M., Sharma, B., Shin, K. A., Shlegel, V. N., Siyeon, K., So, J., Sokur, N. V., Son, J. K., Song, J. W., Srisittipokakun, N., Tretyak, V. I., Wirawan, R., Woo, K. R., Yeon, H. J., Yoon, Y. S., and Yue, Q.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

AMoRE searches for the signature of neutrinoless double beta decay of $^{100}$Mo with a 100 kg sample of enriched $^{100}$Mo. Scintillating molybdate crystals coupled with a metallic magnetic calorimeter operate at milli-Kelvin temperatures to measure the energy of electrons emitted in the decay. As a demonstration of the full-scale AMoRE, we conducted AMoRE-I, a pre-experiment with 18 molybdate crystals, at the Yangyang Underground Laboratory for over two years. The exposure was 8.02 kg$\cdot$year (or 3.89 kg$_{\mathrm{^{100}Mo}}\cdot$year) and the total background rate near the Q-value was 0.025 $\pm$ 0.002 counts/keV/kg/year. We observed no indication of $0\nu\beta\beta$ decay and report a new lower limit of the half-life of $^{100}$Mo $0\nu\beta\beta$ decay as $ T^{0\nu}_{1/2}>3.0\times10^{24}~\mathrm{years}$ at 90\% confidence level. The effective Majorana mass limit range is $m_{\beta\beta}<$(210--610) meV using nuclear matrix elements estimated in the framework of different models, including the recent shell model calculations., Comment: 7 pages, 4 figures

Published
2024

8. Projected background and sensitivity of AMoRE-II

Author

Agrawal, A., Alenkov, V. V., Aryal, P., Beyer, J., Bhandari, B., Boiko, R. S., Boonin, K., Buzanov, O., Byeon, C. R., Chanthima, N., Cheoun, M. K., Choe, J. S., Choi, Seonho, Choudhury, S., Chung, J. S., Danevich, F. A., Djamal, M., Drung, D., Enss, C., Fleischmann, A., Gangapshev, A. M., Gastaldo, L., Gavrilyuk, Y. M., Gezhaev, A. M., Gileva, O., Grigorieva, V. D., Gurentsov, V. I., Ha, C., Ha, D. H., Ha, E. J., Hwnag, D. H., Jeona, E. J., Jeon, J. A., Jo, H. S., Kaewkhao, J., Kang, C. S., Kang, W. G., Kazalov, V. V., Kempf, S., Khan, A., Khan, S., Kim, D. Y., Kim, G. W., Kim, H. B., Kim, Ho-Jong, Kim, H. J., Kim, H. L., Kim, H. S., Kim, M. B., Kim, S. C., Kim, S. K., Kim, S. R., Kim, W. T., Kim, Y. D., Kim, Y. H., Kirdsiri, K., Ko, Y. J., Kobychev, V. V., Kuzminov, V. Kornoukhov V. V., Kwon, D. H., Lee, C. H., Lee, DongYeup, Lee, E. K., Lee, H. J., Lee, H. S., Lee, J., Lee, J. Y., Lee, K. B., Lee, M. H., Lee, M. K., Lee, S. W., Lee, Y. C., Leonard, D. S., Lim, H. S., Mailyan, B., Makarov, E. P., Nyanda, P., Oh, Y., Olsen, S. L., Panasenko, S. I., Park, H. K., Park, H. S., Park, K. S., Park, S. Y., Polischuk, O. G., Prihtiadi, H., Ra, S., Rooh, S. S. Ratkevich G., Sari, M. B., Seob, J., Seo, K. M., Sharma, B., Shin, K. A., Shlegel, V. N., Siyeon, K., So, J., Sokur, N. V., Son, J. K., Song, J. W., Srisittipokakun, N., Tretyak, V. I., Wirawan, R., Woo, K. R., Yeon, H. J., Yoon, Y. S., and Yue, Q.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

AMoRE-II aims to search for neutrinoless double beta decay with an array of 423 Li$_2$$^{100}$MoO$_4$ crystals operating in the cryogenic system as the main phase of the Advanced Molybdenum-based Rare process Experiment (AMoRE). AMoRE has been planned to operate in three phases: AMoRE-pilot, AMoRE-I, and AMoRE-II. AMoRE-II is currently being installed at the Yemi Underground Laboratory, located approximately 1000 meters deep in Jeongseon, Korea. The goal of AMoRE-II is to reach up to $T^{0\nu\beta\beta}_{1/2}$ $\sim$ 6 $\times$ 10$^{26}$ years, corresponding to an effective Majorana mass of 15 - 29 meV, covering all the inverted mass hierarchy regions. To achieve this, the background level of the experimental configurations and possible background sources of gamma and beta events should be well understood. We have intensively performed Monte Carlo simulations using the GEANT4 toolkit in all the experimental configurations with potential sources. We report the estimated background level that meets the 10$^{-4}$counts/(keV$\cdot$kg$\cdot$yr) requirement for AMoRE-II in the region of interest (ROI) and show the projected half-life sensitivity based on the simulation study.

Published
2024

9. Upgrade of NaI(Tl) crystal encapsulation for the NEON experiment

Author

Choi, J. J., Jeon, E. J., Kim, J. Y., Kim, K. W., Kim, S. H., Kim, S. K., Kim, Y. D., Ko, Y. J., Koh, B. C., Ha, C., Park, B. J., Lee, S. H., Lee, I. S., Lee, H., Lee, H. S., Lee, J., and Oh, Y. M.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

The Neutrino Elastic-scattering Observation with NaI(Tl) experiment (NEON) aims to detect coherent elastic neutrino-nucleus scattering~(\cenns) in a NaI(Tl) crystal using reactor anti-electron neutrinos at the Hanbit nuclear power plant complex. A total of 13.3 kg of NaI(Tl) crystals were initially installed in December 2020 at the tendon gallery, 23.7$\pm$0.3\,m away from the reactor core, which operates at a thermal power of 2.8\,GW. Initial engineering operation was performed from May 2021 to March 2022 and observed unexpected photomultiplier-induced noise and a decreased light yield that were caused by leakage of liquid scintillator into the detector due to weakness of detector encapsulation. We upgraded the detector encapsulation design to prevent the leakage of the liquid scintillator. Meanwhile two small-sized detectors were replaced with larger ones resulting in a total mass of 16.7\,kg. With this new design implementation, the detector system has been operating stably since April 2022 for over a year without detector gain drop. In this paper, we present an improved crystal encapsulation design and stability of the NEON experiment.

Published
2024

10. Waveform Simulation for Scintillation Characteristics of NaI(Tl) Crystal

Author

Choi, J. J., Ha, C., Jeon, E. J., Kim, K. W., Kim, S. K., Kim, Y. D., Ko, Y. J., Koh, B. C., Lee, H. S., Lee, S. H., Lee, S. M., Park, B. J., and Yu, G. H.

Subjects
Physics - Instrumentation and Detectors
Abstract

The lowering of the energy threshold in the NaI detector is crucial not only for comprehensive validation of DAMA/LIBRA but also for exploring new possibilities in the search for low-mass dark matter and observing coherent elastic scattering between neutrino and nucleus. Alongside hardware enhancements, extensive efforts have focused on refining event selection to discern noise, achieved through parameter development and the application of machine learning. Acquiring pure, unbiased datasets is crucial in this endeavor, for which a waveform simulation was developed. The simulation data were compared with the experimental data using several pulse shape discrimination parameters to test its performance in describing the experimental data. Additionally, we present the outcomes of multi-variable machine learning trained with simulation data as a scintillation signal sample. The distributions of outcomes for experimental and simulation data show a good agreement. As an application of the waveform simulation, we validate the trigger efficiency alongside estimations derived from the minimally biased measurement data.

Published
2024
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11. Measurements of low-energy nuclear recoil quenching factors for Na and I recoils in the NaI(Tl) scintillator

Author

Lee, S. H., Joo, H. W., Kim, H. J., Kim, K. W., Kim, S. K., Kim, Y. D., Ko, Y. J., Lee, H. S., Lee, J. Y., Park, H. S., and Yoon, Y. S.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

Elastic scattering off nuclei in target detectors, involving interactions with dark matter and coherent elastic neutrino nuclear recoil (CE$\nu$NS), results in the deposition of low energy within the nuclei, dissipating rapidly through a combination of heat and ionization. The primary energy loss mechanism for nuclear recoil is heat, leading to consistently smaller measurable scintillation signals compared to electron recoils of the same energy. The nuclear recoil quenching factor (QF), representing the ratio of scintillation light yield produced by nuclear recoil to that of electron recoil at the same energy, is a critical parameter for understanding dark matter and neutrino interactions with nuclei. The low energy QF of NaI(Tl) crystals, commonly employed in dark matter searches and CE$\nu$NS measurements, is of substantial importance. Previous low energy QF measurements were constrained by contamination from photomultiplier tube (PMT)-induced noise, resulting in an observed light yield of approximately 15 photoelectrons per keVee (kilo-electron-volt electron-equivalent energy) and nuclear recoil energy above 5 keVnr (kilo-electron-volt nuclear recoil energy). Through enhanced crystal encapsulation, an increased light yield of around 26 photoelectrons per keVee is achieved. This improvement enables the measurement of the nuclear recoil QF for sodium nuclei at an energy of 3.8 $\pm$ 0.6 keVnr with a QF of 11.2 $\pm$ 1.7%. Furthermore, a reevaluation of previously reported QF results is conducted, incorporating enhancements in low energy events based on waveform simulation. The outcomes are generally consistent with various recent QF measurements for sodium and iodine.

Published
2024

12. Background study of the AMoRE-pilot experiment

Author

Agrawal, A., Alenkov, V. V., Aryal, P., Beyer, J., Bhandari, B., Boiko, R. S., Boonin, K., Buzanov, O., Byeon, C. R., Chanthima, N., Cheoun, M. K., Choe, J. S., Choi, Seonho, Choudhury, S., Chung, J. S., Danevich, F. A., Djamal, M., Drung, D., Enss, C., Fleischmann, A., Gangapshev, A. M., Gastaldo, L., Gavrilyuk, Yu. M., Gezhaev, A. M., Gileva, O., Grigorieva, V. D., Gurentsov, V. I., Ha, C., Ha, D. H., Ha, E. J., Hwang, D. H., Jeon, E. J., Jeon, J. A., Jo, H. S., Kaewkhao, J., Kang, C. S., Kang, W. G., Kazalov, V. V., Kempf, S., Khan, A., Khan, S., Kim, D. Y., Kim, G. W., Kim, H. B., Kim, Ho-Jong, Kim, H. J., Kim, H. L., Kim, H. S., Kim, M. B., Kim, S. C., Kim, S. K., Kim, S. R., Kim, W. T., Kim, Y. D., Kim, Y. H., Kirdsiri, K., Ko, Y. J., Kobychev, V. V., Kornoukhov, V., Kuzminov, V. V., Kwon, D. H., Lee, C. H., Lee, DongYeup, Lee, E. K., Lee, H. J., Lee, H. S., Lee, J., Lee, J. Y., Lee, K. B., Lee, M. H., Lee, M. K., Lee, S. W., Lee, Y. C., Leonard, D. S., Lim, H. S., Mailyan, B., Makarov, E. P., Nyanda, P., Oh, Y., Olsen, S. L., Panasenko, S. I., Park, H. K., Park, H. S., Park, K. S., Park, S. Y., Polischuk, O. G., Prihtiadi, H., Ra, S., Ratkevich, S. S., Rooh, G., Sari, M. B., Seo, J., Seo, K. M., Sharma, B., Shin, K. A., Shlegel, V. N., Siyeon, K., So, J., Sokur, N. V., Son, J. K., Song, J. W., Srisittipokakun, N., Tretyak, V. I., Wirawan, R., Woo, K. R., Yeon, H. J., Yoon, Y. S., and Yue, Q.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report a study on the background of the Advanced Molybdenum-Based Rare process Experiment (AMoRE), a search for neutrinoless double beta decay (\znbb) of $^{100}$Mo. The pilot stage of the experiment was conducted using $\sim$1.9 kg of \CAMOO~ crystals at the Yangyang Underground Laboratory, South Korea, from 2015 to 2018. We compared the measured $\beta/\gamma$ energy spectra in three experimental configurations with the results of Monte Carlo simulations and identified the background sources in each configuration. We replaced several detector components and enhanced the neutron shielding to lower the background level between configurations. A limit on the half-life of $0\nu\beta\beta$ decay of $^{100}$Mo was found at $T_{1/2}^{0\nu} \ge 3.0\times 10^{23}$ years at 90\% confidence level, based on the measured background and its modeling. Further reduction of the background rate in the AMoRE-I and AMoRE-II are discussed.

Published
2024

13. Nonproportionality of NaI(Tl) Scintillation Detector for Dark Matter Search Experiments

Author

Lee, S. M., Adhikari, G., Carlin, N., Cho, J. Y., Choi, J. J., Choi, S., Ezeribe, A. C., a, L. E. Fran., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, S. W., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, Y. J., Leonard, D. S., Luan, N. T., Manzato, B. B., Maruyama, R. H., Neal, R. J., Nikkel, J. A., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, J. C., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Scarff, A., Son, M. K., Spooner, N. J. C., Truc, L. T., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We present a comprehensive study of the nonproportionality of NaI(Tl) scintillation detectors within the context of dark matter search experiments. Our investigation, which integrates COSINE-100 data with supplementary $\gamma$ spectroscopy, measures light yields across diverse energy levels from full-energy $\gamma$ peaks produced by the decays of various isotopes. These $\gamma$ peaks of interest were produced by decays supported by both long and short-lived isotopes. Analyzing peaks from decays supported only by short-lived isotopes presented a unique challenge due to their limited statistics and overlapping energies, which was overcome by long-term data collection and a time-dependent analysis. A key achievement is the direct measurement of the 0.87 keV light yield, resulting from the cascade following electron capture decay of $^{22}$Na from internal contamination. This measurement, previously accessible only indirectly, deepens our understanding of NaI(Tl) scintillator behavior in the region of interest for dark matter searches. This study holds substantial implications for background modeling and the interpretation of dark matter signals in NaI(Tl) experiments., Comment: 12 pages, 7 figures

Published
2024
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14. Scintillation characteristics of an undoped CsI crystal at low-temperature for dark matter search

Author

Kim, W. K., Lee, H. Y., Kim, K. W., Ko, Y. J., Jeon, J. A., Kim, H. J., and Lee, H. S.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

The scintillation characteristics of 1 g undoped CsI crystal were studied by directly coupling two silicon photomultipliers (SiPMs) over a temperature range from room temperature to 86 K. The scintillation decay time and light output were measured using x-ray and gamma-ray peaks from a $^{109}$Cd radioactive source. An increase in decay time was observed as the temperature decreased from room temperature to 86 K, ranging from 76 ns to 605 ns. The light output increased as well, reaching 37.9 $\pm$ 1.5 photoelectrons per keV electron-equivalent at 86 K, which is approximately 18 times higher than the light yield at room temperature. Leveraging the significantly enhanced scintillation light output of the undoped CsI crystal at low temperature, coupling it with SiPMs results into a promising detector for dark matter search. Both cesium and iodine have a proton odd number, thus they are suitable targets to probe dark matter-proton spin dependent interactions. We evaluated the sensitivity of the detector here proposed to light dark matter-proton spin dependent interactions. We included the Migdal effect and assumed 200\,kg of undoped CsI crystals for the dark matter search. We conclude that undoped CsI coupled to SiPM can exhibit world-competitive sensitivities for low-mass dark matter detection, particularly for the dark matter-proton spin-dependent interaction.

Published
2023

15. Alpha backgrounds in NaI(Tl) crystals of COSINE-100

Author

Adhikari, G., Carlin, N., Cavalcante, D. F. F. S., Cho, J. Y., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, S. W., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Luan, N. T., Manzato, B. B., Maruyama, R. H., Neal, R. J., Nikkel, J. A., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, J. C., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Scar, A., Shin, K. A., Son, M. K., Spooner, N. J. C., Truc, L. T., Yang, L., Yu, G. H., and COSINE-100, for

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

COSINE-100 is a dark matter direct detection experiment with 106 kg NaI(Tl) as the target material. 210Pb and daughter isotopes are a dominant background in the WIMP region of interest and are detected via beta decay and alpha decay. Analysis of the alpha channel complements the background model as observed in the beta/gamma channel. We present the measurement of the quenching factors and Monte Carlo simulation results and activity quantification of the alpha decay components of the COSINE-100 NaI(Tl) crystals. The data strongly indicate that the alpha decays probabilistically undergo two possible quenching factors but require further investigation. The fitted results are consistent with independent measurements and improve the overall understanding of the COSINE-100 backgrounds. Furthermore, the half-life of 216Po has been measured to be 143.4 +/- 1.2 ms, which is consistent with and more precise than recent measurements.

Published
2023
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16. Search for inelastic WIMP-iodine scattering with COSINE-100

Author

Adhikari, G., Carlin, N., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, S., Luan, N. T., Manzato, B. B., Maruyama, R. H., Neal, R. J., Nikkel, J. A., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We report the results of a search for inelastic scattering of weakly interacting massive particles (WIMPs) off $^{127}$I nuclei using NaI(Tl) crystals with a data exposure of 97.7 kg$\cdot$years from the COSINE-100 experiment. The signature of inelastic WIMP-$^{127}$I scattering is a nuclear recoil accompanied by a 57.6 keV $\gamma$-ray from the prompt deexcitation, producing a more energetic signal compared to the typical WIMP nuclear recoil signal. We found no evidence for this inelastic scattering signature and set a 90 $\%$ confidence level upper limit on the WIMP-proton spin-dependent, inelastic scattering cross section of $1.2 \times 10^{-37} {\rm cm^{2}}$ at the WIMP mass 500 ${\rm GeV/c^{2}}$., Comment: 8 pages, 5 figures. arXiv admin note: text overlap with arXiv:2104.03537

Published
2023
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17. Search for Boosted Dark Matter in COSINE-100

Author

Adhikari, G., Carlin, N., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Luan, N. T., Manzato, B. B., Maruyama, R. H., Neal, R. J., Nikkel, J. A., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment
Abstract

We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.7 kg$\cdot$years exposure, we set limits on BDM interactions under a variety of hypotheses. Notably, we explored the dark photon parameter space, leading to competitive limits compared to direct dark photon search experiments, particularly for dark photon masses below 4\,MeV and considering the invisible decay mode. Furthermore, by comparing our results with a previous BDM search conducted by the Super-Kamionkande experiment, we found that the COSINE-100 detector has advantages in searching for low-mass dark matter. This analysis demonstrates the potential of the COSINE-100 detector to search for MeV electron recoil signals produced by the dark sector particle interactions., Comment: 7 pages, 4 figures

Published
2023
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18. Search for bosonic super-weakly interacting massive particles at COSINE-100

Author

Adhikari, G., Carlin, N., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Luan, N. T., Manzato, B. B., Maruyama, R. H., Neal, R. J., Nikkel, J. A., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

We present results of a search for bosonic super-weakly interacting massive particles (BSW) as keV scale dark matter candidates that is based on an exposure of 97.7 kg$\cdot$year from the COSINE experiment. In this search, we employ, for the first time, Compton-like as well as absorption processes for pseudoscalar and vector BSWs. No evidence for BSWs is found in the mass range from 10 $\mathrm{keV/c}^2$ to 1 $\mathrm{MeV/c}^2$, and we present the exclusion limits on the dimensionless coupling constants to electrons $g_{ae}$ for pseudoscalar and $\kappa$ for vector BSWs at 90% confidence level. Our results show that these limits are improved by including the Compton-like process in masses of BSW, above $\mathcal{O}(100\,\mathrm{keV/c}^2)$.

Published
2023
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19. Global gradient estimates for the mixed local and nonlocal problems with measurable nonlinearities

Author

Byun, S. -S., Kumar, D., and Lee, H. -S.

Subjects
Mathematics - Analysis of PDEs
Abstract

A non-homogeneous mixed local and nonlocal problem in divergence form is investigated for the validity of the global Calder\'on-Zygmund estimate for the weak solution to the Dirichlet problem of a nonlinear elliptic equation. We establish an optimal Calder\'on-Zygmund theory by finding not only a minimal regularity requirement on the mixed local and nonlocal operators but also a lower level of geometric assumption on the boundary of the domain for the global gradient estimate. More precisely, assuming that the nonlinearity of the local operator, whose prototype is the classical $(-\Delta_p)^1$-Laplace operator with $1

Published
2023

20. Search for solar bosonic dark matter annual modulation with COSINE-100

Author

Adhikari, G., Carlin, N., Choi, J. J., Choi, S., Ezeribe, A. C., França, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Luan, N. T., Manzato, B. B., Maruyama, R. H., Neal, R. J., Nikkel, J. A., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment
Abstract

We present results from a search for solar bosonic dark matter using the annual modulation method with the COSINE-100 experiment. The results were interpreted considering three dark sector bosons models: solar dark photon; DFSZ and KSVZ solar axion; and Kaluza-Klein solar axion. No modulation signal that is compatible with the expected from the models was found from a data-set of 2.82 yr, using 61.3 kg of NaI(Tl) crystals. Therefore, we set a 90$\%$ confidence level upper limits for each of the three models studied. For the solar dark photon model, the most stringent mixing parameter upper limit is $1.61 \times 10^{-14}$ for dark photons with a mass of 215 eV. For the DFSZ and KSVZ solar axion, and the Kaluza-Klein axion models, the upper limits exclude axion-electron couplings, $g_{ae}$, above $1.61 \times 10^{-11}$ for axion mass below 0.2 keV; and axion-photon couplings, $g_{a\gamma\gamma}$, above $1.83 \times 10^{-11}$ GeV$^{-1}$ for an axion number density of $4.07 \times 10^{13}$ cm$^{-3}$. This is the first experimental search for solar dark photons and DFSZ and KSVZ solar axions using the annual modulation method. The lower background, higher light yield and reduced threshold of NaI(Tl) crystals of the future COSINE-200 experiment are expected to enhance the sensitivity of the analysis shown in this paper. We show the sensitivities for the three models studied, considering the same search method with COSINE-200., Comment: 13 pages, 16 figures

Published
2023
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21. Isoscaling in central Sn+Sn collisions at 270 MeV/u

Author

Lee, J. W., Tsang, M. B., Tsang, C. Y., Wang, R., Barney, J., Estee, J., Isobe, T., Kaneko, M., Kurata-Nishimura, M., Lynch, W. G., Murakami, T., Ono, A., Souza, S. R., Ahn, D. S., Atar, L., Aumann, T., Baba, H., Boretzky, K., Brzychczyk, J., Cerizza, G., Chiga, N., Fukuda, N., Gasparic, I., Hong, B., Horvat, A., Ieki, K., Ikeno, N., Inabe, N., Jhang, G., Kim, Y. J., Kobayashi, T., Kondo, Y., Lasko, P., Lee, H. S., Leifels, Y., Łukasik, J., Manfredi, J., McIntosh, A. B., Morfouace, P., Nakamura, T., Nakatsuka, N., Nishimura, S., Otsu, H., Pawłowski, P., Pelczar, K., Rossi, D., Sakurai, H., Santamaria, C., Sato, H., Scheit, H., Shane, R., Shimizu, Y., Simon, H., Snoch, A., Sochocka, A., Sumikama, T., Suzuki, H., Suzuki, D., Takeda, H., Tangwancharoen, S., Togano, Y., Xiao, Z. G., Yennello, S. J., and Zhang, Y.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Experimental information on fragment emissions is important in understanding the dynamics of nuclear collisions and in the development of transport model simulating heavy-ion collisions. The composition of complex fragments emitted in the heavy-ion collisions can be explained by statistical models, which assume that thermal equilibrium is achieved at collision energies below 100 MeV/u. Our new experimental data together with theoretical analyses for light particles from Sn+Sn collisions at 270 MeV/u, suggest that the hypothesis of thermal equilibrium breaks down for particles emitted with high transfer momentum. To inspect the system's properties in such limit, the scaling features of the yield ratios of particles from two systems, a neutron-rich system of ${}^{132}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ and a nearly symmetric system of ${}^{108}\mathrm{Sn}+{}^{112}\mathrm{Sn}$, are examined in the framework of the statistical multifragmentation model and the antisymmetrized molecular dynamics model. The isoscaling from low energy particles agree with both models. However the observed breakdown of isoscaling for particles with high transverse momentum cannot be explained by the antisymmetrized molecular dynamics model.

Published
2022
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22. Status and performance of the AMoRE-I experiment on neutrinoless double beta decay

Author

Kim, H. B., Ha, D. H., Jeon, E. J., Jeon, J. A., Jo, H. S., Kang, C. S., Kang, W. G., Kim, H. S., Kim, S. C., Kim, S. G., Kim, S. K., Kim, S. R., Kim, W. T., Kim, Y. D., Kim, Y. H., Kwon, D. H., Lee, E. S., Lee, H. J., Lee, H. S., Lee, J. S., Lee, M. H., Lee, S. W., Lee, Y. C., Leonard, D. S., Lim, H. S., Mailyan, B., Nyanda, P. B., Oh, Y. M., Sari, M. B., Seo, J. W., Seo, K. M., Seo, S. H., So, J. H., Woo, K. R., and Yoon, Y. S.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract

AMoRE is an international project to search for the neutrinoless double beta decay of $^{100}$Mo using a detection technology consisting of magnetic microcalorimeters (MMCs) and molybdenum-based scintillating crystals. Data collection has begun for the current AMORE-I phase of the project, an upgrade from the previous pilot phase. AMoRE-I employs thirteen $^\mathrm{48depl.}$Ca$^{100}$MoO$_4$ crystals and five Li$_2$$^{100}$MoO$_4$ crystals for a total crystal mass of 6.2 kg. Each detector module contains a scintillating crystal with two MMC channels for heat and light detection. We report the present status of the experiment and the performance of the detector modules., Comment: 8 pages, 4 figures, published in Journal of Low Temperature Physics (2022)

Published
2022
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24. Radon concentration variations at the Yangyang underground laboratory

Author

Ha, C., Jeong, Y., Kang, W. G., Kim, J., Kim, K. W., Kim, S. K., Kim, Y. D., Lee, H. S., Lee, M. H., Lee, M. J., Lee, Y. J., and Seo, K. M.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract

The concentration of radon in the air has been measured in the 700 m-deep Yangyang underground laboratory between October 2004 and May 2022. The average concentrations in two experimental areas, called A6 and A5, were measured to be 53.4$\pm$0.2 Bq/m3 and 33.5$\pm$0.1 Bq/m3, respectively. The lower value in the A5 area reflects the presence of better temperature control and ventilation. The radon concentrations sampled within the two A5 experimental rooms' air are found to be correlated to the local surface temperature outside of the rooms, with correlation coefficients r = 0.22 and r = 0.70. Therefore, the radon concentrations display a seasonal variation, because the local temperature driven by the overground season influences air ventilation in the experimental areas. A fit on the annual residual concentrations finds that the amplitude occurs each year on August, 31$\pm$6 days., Comment: 8 pages, 7 figures

Published
2022

25. An induced annual modulation signature in COSINE-100 data by DAMA/LIBRA's analysis method

Author

Adhikari, G., Carlin, N., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Lee, Y. J., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Nikkel, J. A., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, Nuclear Experiment
Abstract

The DAMA/LIBRA collaboration has reported the observation of an annual modulation in the event rate that has been attributed to dark matter interactions over the last two decades. However, even though tremendous efforts to detect similar dark matter interactions were pursued, no definitive evidence has been observed to corroborate the DAMA/LIBRA signal. Many studies assuming various dark matter models have attempted to reconcile DAMA/LIBRA's modulation signals and null results from other experiments, however no clear conclusion can be drawn. Apart from the dark matter hypothesis, several studies have examined the possibility that the modulation is induced by variations in their detector's environment or their specific analysis methods. In particular, a recent study presents a possible cause of the annual modulation from an analysis method adopted by the DAMA/LIBRA experiment in which the observed annual modulation could be reproduced by a slowly varying time-dependent background. Here, we study the COSINE-100 data using an analysis method similar to the one adopted by the DAMA/LIBRA experiment and observe a significant annual modulation, although the modulation phase is almost opposite to that of the DAMA/LIBRA data. Assuming the same background composition for COSINE-100 and DAMA/LIBRA, simulated experiments for the DAMA/LIBRA without dark matter signals also provide significant annual modulation with an amplitude similar to DAMA/LIBRA with opposite phase. Even though this observation does not explain the DAMA/LIBRA's results directly, this interesting phenomenon motivates deeper studies of the time-dependent DAMA/LIBRA background data.

Published
2022
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26. Exploring coherent elastic neutrino-nucleus scattering using reactor electron antineutrinos in the NEON experiment

Author

Choi, J. J., Jeon, E. J., Kim, J. Y., Kim, K. W., Kim, S. H., Kim, S. K., Kim, Y. D., Ko, Y. J., Koh, B. C., Ha, C., Park, B. J., Lee, S. H., Lee, I. S., Lee, H., Lee, H. S., Lee, J., and Oh, Y. M.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

Neutrino elastic scattering observation with NaI (NEON) is an experiment designed to detect neutrino-nucleus coherent scattering using reactor electron antineutrinos. NEON is based on an array of six NaI(Tl) crystals with a total mass of 13.3 kg, located at the tendon gallery that is 23.7 m away from a reactor core with a thermal power of 2.8 GW in the Hanbit nuclear power complex. The installation of the NEON detector was completed in December 2020, and since May 2021, the detector has acquired data at full reactor power. Based on the observed light yields of the NaI crystals of approximately 22, number of photoelectrons per unit keV electron-equivalent energy (keVee), and 6 counts/kg/keV/day background level at 2-6 keVee energy, coherent elastic neutrino-nucleus scattering observation sensitivity is evaluated as more than 3$\sigma$ assuming one-year reactor-on and 100 days reactor-off data, 0.2 keVee energy threshold, and 7 counts/keV/kg/day background in the signal region of 0.2-0.5 keVee. This paper describes the design of the NEON detector, including the shielding arrangement, configuration of NaI(Tl) crystals, and associated operating systems. The initial performance and associated sensitivity of the experiment are also presented., Comment: 21 pages 27 figures

Published
2022
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27. Coherent elastic neutrino-nucleus scattering: Terrestrial and astrophysical applications

Author

Abdullah, M., Abele, H., Akimov, D., Angloher, G., Aristizabal-Sierra, D., Augier, C., Balantekin, A. B., Balogh, L., Barbeau, P. S., Baudis, L., Baxter, A. L., Beaufort, C., Beaulieu, G., Belov, V., Bento, A., Berge, L., Bernardi, I. A., Billard, J., Bolozdynya, A., Bonhomme, A., Bres, G., Bret, J-. L., Broniatowski, A., Brossard, A., Buck, C., Cadeddu, M., Calvo, M., Canonica, L., Cappella, F., Cardani, L., Casali, N., Cazes, A., Cerulli, R., Chaize, D., Chang, C., Chapellier, M., Chaplinsky, L., Chemin, G., Chen, R., Colantoni, I., Colas, J., Coloma, P., Corcoran, E. C., Crawford, S., Cruciani, A., Fard, A. Dastgheibi, De Jesus, M., de Marcillac, P., De Romeri, V., del Castello, G., del GalloRoccagiovine, M., Delicato, D., Demarteau, M., Deng, Y., Dent, J. B., Denton, P. B., Dering, K., Doblhammer, A., Dordei, F., Dorer, S., Dumoulin, L., Dunford, D., Dutta, B., Erhart, A., Exshaw, O., Ferriol, S., Figueroa-Feliciano, E., Filippini, J. B., Flores, L . J., Formaggio, J. A., Friedl, M., Fuard, S., Gao, F., Garai, A., Garces, E. A., Gascon, J., Gehrlein, J., Gerbier, G., Ghete, V. M., Giomataris, I., Giroux, G., Giuliani, A., Giunti, C., Gorel, P., Goupy, C., Goupy, J., Goy, C., Green, M. P., Gros, M., Guerin, C., Guidi, V., Guillaudin, O., Guy, E., Ha, C., Hauff, D., Hakenmuller, J., Harrington, P. M., Hedges, S., Heine, S. T., Hertel, S., Heusch, M., Hoarau, C., Hoferichter, M., Hoppe, E. W., Hong, Z., Horiuchi, S., Huber, P., Ianigro, J. C., Jachowicz, N., Jericha, E., Jin, Y., Johnston, J. P., Juillard, A., Katsioulas, I., Kazarcev, S., Kaznacheeva, M., Kelly, F., Kelly, K. J., Kim, D., Kinast, A., Klinkenberg, L., Kluck, H., Knights, P., Ko, Y. J., Kosmas, T. S., Kwon, L., Lamblin, J., Lang, R. F., Langenkamper, A., Langrock, S., Lasserre, T., Lattaud, H., Lautridou, P., Lee, H. S., Lenardo, B. G., Lhuillier, D., Li, M., Li, S. C., Li, Y. F., Li, Z., Lindner, M., Liu, J., Loomba, D., Lubashevskiy, A., Machado, P. A. N., Mancuso, M., Maneschg, W., Markoff, D. M., Marnieros, S., Martin, R., Martin, R. D., Mauri, B., Mayer, D. W., Mazzolari, A., Mazzucato, E., Menendez, J., Minet, J., Miranda, O. G., Misiak, D., Mols, J. -P., Monfardini, A., Mounier, F., Muraz, J. F., Neep, T., Neilson, R., Newby, J., Newstead, J. L., Neyrial, H., Ni, K., Nikolopoulos, K., Nones, C., Norcini, D., Pandey, V., O'Brien, P., O'Hare, C. A. J., Oberauer, L., Oliver, W., Olivieri, E., Onillon, A., Oriol, C., Ortmann, T., Owen, R., Palladino, K. J., Papoulias, D. K., Park, J. C., Parno, D. S., Patel, P. K., Pattavina, L., Peinado, E., Perbet, E., Peters, L., Petricca, F., Pinckney, H. D., Piro, M. -C., Ponomarev, D., Poda, D., Potzel, W., Probst, F., Pucci, F., Rarbi, F., Rapp, R., Ray, H., Real, J. -S., Reindl, F., Rich, G. C., Ricol, J. S., Rink, T., Redon, T., Rogly, R., Robert, A., Rothe, J., Rozov, S., Rozova, I., Salagnac, T., Garcia, E. Sanchez, Garcia, G. Sanchez, Sanders, O., Sanglard, V., Santos, D., Sarkis, Y., Savu, V., Savvidis, G., Savvidis, I., Schermer, N., Schieck, J., Schmidt, B., Schonert, S., Scholberg, K., Schwenk, A., Schwertner, C., Scola, L., Shevchik, Ye., Shin, S., Sibille, V., Shoemaker, I. M., Snowden-Ifft, D. P., Soldner, T., Soum, G., Spooner, N. J. C., Stachurska, J., Stodolsky, L., Strauss, R., Strigari, L. E., Stutz, A., Suh, B. D., Suhonen, J., Tabrizi, Z., Takhistov, V., Thompson, A., Tomei, C., Tortola, M., Tripathi, M., Vagneron, L., Valle, J. W. F., Mirbach, K. v., Van De Ponteseele, W., Vignati, M., Vivier, M., Fernandez, F. Vazquez de Sola, Vezzu, F., Vidal, M., Wagner, V., Walker, J. W., Ward, R., Wex, A., Winslow, L., Wong, H. T., Wood, M. H., Xu, J., Yang, L., Yakushev, E., Zampaolo, M., Zettlemoyer, J., Zhang, Y. Y., and Zinatulina, D.

Subjects
High Energy Physics - Phenomenology, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) is a process in which neutrinos scatter on a nucleus which acts as a single particle. Though the total cross section is large by neutrino standards, CE$\nu$NS has long proven difficult to detect, since the deposited energy into the nucleus is $\sim$ keV. In 2017, the COHERENT collaboration announced the detection of CE$\nu$NS using a stopped-pion source with CsI detectors, followed up the detection of CE$\nu$NS using an Ar target. The detection of CE$\nu$NS has spawned a flurry of activities in high-energy physics, inspiring new constraints on beyond the Standard Model (BSM) physics, and new experimental methods. The CE$\nu$NS process has important implications for not only high-energy physics, but also astrophysics, nuclear physics, and beyond. This whitepaper discusses the scientific importance of CE$\nu$NS, highlighting how present experiments such as COHERENT are informing theory, and also how future experiments will provide a wealth of information across the aforementioned fields of physics., Comment: contribution to Snowmasss 2021. Contact authors: P. S. Barbeau, R. Strauss, L. E. Strigari

Published
2022

28. Three-year annual modulation search with COSINE-100

Author

Collaboration, COSINE-100, Adhikari, G., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Ezeribe, A. C., França, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Kwon, H. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

COSINE-100 is a direct detection dark matter experiment that aims to test DAMA/LIBRA's claim of dark matter discovery by searching for a dark matter-induced annual modulation signal with NaI(Tl) detectors. We present new constraints on the annual modulation signal from a dataset with a 2.82 yr livetime utilizing an active mass of 61.3 kg, for a total exposure of 173 kg$\cdot$yr. This new result features an improved event selection that allows for both lowering the energy threshold to 1 keV and a more precise time-dependent background model. In the 1-6 keV and 2-6 keV energy intervals, we observe best-fit values for the modulation amplitude of 0.0067$\pm$0.0042 and 0.0051$\pm$0.0047 counts/(day$\cdot$kg$\cdot$keV), respectively, with a phase fixed at 152.5 days., Comment: 11 pages, 8 figures

Published
2021
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29. Study on NaI(Tl) crystal at -35 C for dark matter detection

Author

Lee, S. H., Kim, G. S., Kim, H. J., Kim, K. W., Lee, J. Y., and Lee, H. S.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We present the responses of a NaI(Tl) crystal in terms of the light yield and pulse shape characteristics of nuclear recoil events at two different temperatures: 22 C (room temperature) and -35 C (low temperature). The light yield is measured using 59.54 keV gamma-rays using a 241Am source relative to the mean charge of single photoelectrons. At the low temperature, we measure a 4.7 +/- 1.3% increase in the light yield compared to that at room temperature. A significantly increased decay time is also observed at the low temperature. The responses to nuclear recoil events are measured using neutrons from a 252Cf source and compared to those to electron recoil events. The measured pulse shape discrimination (PSD) power of the NaI(Tl) crystal at the low temperature is found to be improved in the entire energy range studied because of the increased light yield and the different scintillation characteristics. We also find an approximately 9% increased quenching factor of alpha-induced events, which is the light yield ratio of alpha recoil to electron recoil, at the low temperature. This supports the possibility of an increased quenching factor of the nuclear recoil events that are known to have similar processes of dark matter interaction. The increased light yield and the improved PSD power of nuclear recoil events enhance the sensitivity for dark matter detection via dark matter-nuclei interactions.

Published
2021
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30. A novel measurement of initial-state gluon radiation in hadron collisions using Drell-Yan events

Author

CDF Collaboration, Aaltonen, T., Amerio, S., Amidei, D., Anastassov, A., Annovi, A., Antos, J., Apollinari, G., Appel, J. A., Arisawa, T., Artikov, A., Asaadi, J., Ashmanskas, W., Auerbach, B., Aurisano, A., Azfar, F., Badgett, W., Bae, T., Barbaro-Galtieri, A., Barnes, V. E., Barnett, B. A., Barria, P., Bartos, P., Bauce, M., Bedeschi, F., Behari, S., Bellettini, G., Bellinger, J., Benjamin, D., Beretvas, A., Bhatti, A., Bland, K. R., Blumenfeld, B., Bocci, A., Bodek, A., Bortoletto, D., Boudreau, J., Boveia, A., Brigliadori, L., Bromberg, C., Brucken, E., Budagov, J., Budd, H. S., Burkett, K., Busetto, G., Bussey, P., Butti, P., Buzatu, A., Calamba, A., Camarda, S., Campanelli, M., Canelli, F., Carls, B., Carlsmith, D., Carosi, R., Carrillo, S., Casal, B., Casarsa, M., Castro, A., Catastini, P., Cauz, D., Cavaliere, V., Cerri, A., Cerrito, L., Chen, Y. C., Chertok, M., Chiarelli, G., Chlachidze, G., Cho, K., Chokheli, D., Clark, A., Clarke, C., Convery, M. E., Conway, J., Corbo, M., Cordelli, M., Cox, C. A., Cox, D. J., Cremonesi, M., Cruz, D., Cuevas, J., Culbertson, R., d'Ascenzo, N., Datta, M., de Barbaro, P., Demortier, L., Deninno, M., D'Errico, M., Devoto, F., Di Canto, A., Di Ruzza, B., Dittmann, J. R., Donati, S., D'Onofrio, M., Dorigo, M., Driutti, A., Ebina, K., Edgar, R., Elagin, A., Erbacher, R., Errede, S., Esham, B., Farrington, S., Ramos, J. P. Fernández, Field, R., Flanagan, G., Forrest, R., Franklin, M., Freeman, J. C., Frisch, H., Funakoshi, Y., Galloni, C., Garfinkel, A. F., Garosi, P., Gerberich, H., Gerchtein, E., Giagu, S., Giakoumopoulou, V., Gibson, K., Ginsburg, C. M., Giokaris, N., Giromini, P., Glagolev, V., Glenzinski, D., Gold, M., Goldin, D., Golossanov, A., Gomez, G., Gomez-Ceballos, G., Goncharov, M., López, O. González, Gorelov, I., Goshaw, A. T., Goulianos, K., Gramellini, E., Grosso-Pilcher, C., da Costa, J. Guimaraes, Hahn, S. R., Han, J. Y., Happacher, F., Hara, K., Hare, M., Harr, R. F., Harrington-Taber, T., Hatakeyama, K., Hays, C., Heinrich, J., Herndon, M., Hocker, A., Hong, Z., Hopkins, W., Hou, S., Hughes, R. E., Husemann, U., Hussein, M., Huston, J., Introzzi, G., Iori, M., Ivanov, A., James, E., Jang, D., Jayatilaka, B., Jeon, E. J., Jindariani, S., Jones, M., Joo, K. K., Jun, S. Y., Junk, T. R., Kambeitz, M., Kamon, T., Karchin, P. E., Kasmi, A., Kato, Y., Ketchum, W., Keung, J., Kilminster, B., Kim, D. H., Kim, H. S., Kim, J. E., Kim, M. J., Kim, S. H., Kim, S. B., Kim, Y. J., Kim, Y. K., Kimura, N., Kirby, M., Kondo, K., Kong, D. J., Konigsberg, J., Kotwal, A. V., Kreps, M., Kroll, J., Kruse, M., Kuhr, T., Kurata, M., Laasanen, A. T., Lammel, S., Lancaster, M., Lannon, K., Latino, G., Lee, H. S., Lee, J. S., Leo, S., Leone, S., Lewis, J. D., Limosani, A., Lipeles, E., Lister, A., Liu, Q., Liu, T., Lockwitz, S., Loginov, A., Lucchesi, D., Lucà, A., Lueck, J., Lujan, P., Lukens, P., Lungu, G., Lys, J., Lysak, R., Madrak, R., Maestro, P., Malik, S., Manca, G., Manousakis-Katsikakis, A., Marchese, L., Margaroli, F., Marino, P., Matera, K., Mattson, M. E., Mazzacane, A., Mazzanti, P., McNulty, R., Mehta, A., Mehtala, P., Mesropian, C., Miao, T., Michielin, E., Mietlicki, D., Mitra, A., Miyake, H., Moed, S., Moggi, N., Moon, C. S., Moore, R., Morello, M. J., Mukherjee, A., Muller, Th., Murat, P., Mussini, M., Nachtman, J., Nagai, Y., Naganoma, J., Nakano, I., Napier, A., Nett, J., Nigmanov, T., Nodulman, L., Noh, S. Y., Norniella, O., Oakes, L., Oh, S. H., Oh, Y. D., Okusawa, T., Orava, R., Ortolan, L., Pagliarone, C., Palencia, E., Palni, P., Papadimitriou, V., Parker, W., Pauletta, G., Paulini, M., Paus, C., Phillips, T. J., Piacentino, G., Pianori, E., Pilot, J., Pitts, K., Plager, C., Pondrom, L., Poprocki, S., Potamianos, K., Pranko, A., Prokoshin, F., Ptohos, F., Punzi, G., Fernández, I. Redondo, Renton, P., Rescigno, M., Rimondi, F., Ristori, L., Robson, A., Rodriguez, T., Rolli, S., Ronzani, M., Roser, R., Rosner, J. L., Ruffini, F., Ruiz, A., Russ, J., Rusu, V., Sakumoto, W. K., Sakurai, Y., Santi, L., Sato, K., Saveliev, V., Savoy-Navarro, A., Schlabach, P., Schmidt, E. E., Schwarz, T., Scodellaro, L., Scuri, F., Seidel, S., Seiya, Y., Semenov, A., Seo, H., Sforza, F., Shalhout, S. Z., Shears, T., Shepard, P. F., Shimojima, M., Shochet, M., Shreyber-Tecker, I., Simonenko, A., Sliwa, K., Smith, J. R., Snider, F. D., Song, H., Sorin, V., Denis, R. St., Stancari, M., Stentz, D., Strologas, J., Sudo, Y., Sukhanov, A., Suslov, I., Takemasa, K., Takeuchi, Y., Tang, J., Tecchio, M., Teng, P. K., Thom, J., Thomson, E., Thukral, V., Toback, D., Tokar, S., Tollefson, K., Tomura, T., Tonelli, D., Torre, S., Torretta, D., Totaro, P., Trovato, M., Ukegawa, F., Uozumi, S., Vázquez, F., Velev, G., Vellidis, C., Vernieri, C., Vidal, M., Vilar, R., Vizán, J., Vogel, M., Volpi, G., Wagner, P., Wallny, R., Wang, S. M., Waters, D., Wester III, W. C., Whiteson, D., Wicklund, A. B., Wilbur, S., Williams, H. H., Wilson, J. S., Wilson, P., Winer, B. L., Wittich, P., Wolbers, S., Wolfmeister, H., Wright, T., Wu, X., Wu, Z., Yamamoto, K., Yamato, D., Yang, T., Yang, U. K., Yang, Y. C., Yao, W. -M., Yeh, G. P., Yi, K., Yoh, J., Yorita, K., Yoshida, T., Yu, G. B., Yu, I., Zanetti, A. M., Zeng, Y., Zhou, C., and Zucchelli, S.

Subjects
High Energy Physics - Experiment
Abstract

A study of initial-state gluon radiation (ISR) in hadron collisions is presented using Drell-Yan (DY) events produced in proton-antiproton collisions by the Tevatron collider at a center-of-mass energy of 1.96 TeV. This paper adopts a novel approach which uses the mean value of the Z/$\gamma^*$ transverse momentum $$ in DY events as a powerful observable to characterize the effect of ISR. In a data sample corresponding to an integrated luminosity of 9.4 fb$^{-1}$ collected with the CDF Run II detector, $$ is measured as a function of the Z/$\gamma^*$ invariant mass. It is found that these two observables have a dependence, $ = -8 + 2.2 \ln m_{DY}^2$ [GeV/c], where $m_{DY}$ is the value of the Z/$\gamma^*$ mass measured in units of GeV/$c^2$. This linear dependence is observed for the first time in this analysis. It may be exploited to model the effect of ISR and constrain its impact in other processes., Comment: 14 pages, 14 figures

Published
2021

31. Searching for low-mass dark matter via Migdal effect in COSINE-100

Author

Adhikari, G., Carlin, N., Choi, J. J., Choi, S., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Hollick, S. J., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, H., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Kwon, H. J., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We report on the search for weakly interacting massive particle (WIMP) dark matter candidates in the galactic halo that interact with sodium and iodine nuclei in the COSINE-100 experiment and produce energetic electrons that accompany recoil nuclei via the the Migdal effect. The WIMP mass sensitivity of previous COSINE-100 searches that relied on the detection of ionization signals produced by target nuclei recoiling from elastic WIMP-nucleus scattering was restricted to WIMP masses above $\sim$5 GeV/$c^2$ by the detectors' 1 keVee energy-electron-equivalent threshold. The search reported here looks for recoil signals enhanced by the Migdal electrons that are ejected during the scattering process. This is particularly effective for the detection of low-mass WIMP scattering from the crystals' sodium nuclei in which a relatively larger fraction of the WIMP's energy is transferred to the nucleus recoil energy and the excitation of its orbital electrons. In this analysis, the low-mass WIMP search window of the COSINE-100 experiment is extended to WIMP mass down to 200 MeV/$c^2$. The low-mass WIMP sensitivity will be further improved by lowering the analysis threshold based on a multivariable analysis technique. We consider the influence of these improvements and recent developments in detector performance to re-evaluate sensitivities for the future COSINE-200 experiment. With a 0.2 keVee analysis threshold and high light-yield NaI(Tl) detectors (22 photoelectrons/keVee), the COSINE-200 experiment can explore low-mass WIMPs down to 20 MeV/$c^2$ and probe previously unexplored regions of parameter space., Comment: 10 pages, 8 figures

Published
2021
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32. Scintillation characteristics of a NaI(Tl) crystal at low-temperature with silicon photomultiplier

Author

Lee, H. Y., Jeon, J. A., Kim, K. W., Kim, W. K., Lee, H. S., and Lee, M. H.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

Scintillation characteristics of a thallium doped sodium iodide (NaI(Tl)) crystal with a dimension of 0.6 x 0.6 x 2 cm3 are studied by attaching a silicon photomultiplier (SiPM) direct to the crystal over a temperature range from 93 to 300 K. The scintillation light output and decay time are measured by irradiating 59.54 keV gamma-rays from a 241Am source. We observed approximately 20% increase in light yield at 230K compared to that at the room temperature. At this condition, the NaI(Tl) crystal coupled with the SiPM can be a good candidate for future dark matter search detector.

Published
2021
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33. Alpha backgrounds in the AMoRE-Pilot experiment

Author

Alenkov, V., Bae, H. W., Beyer, J., Boiko, R. S., Boonin, K., Buzanov, O., Chanthima, N., Cheoun, M. K., Choi, S. H., Danevich, F. A., Djamal, M., Drung, D., Enss, C., Fleischmann, A., Gangapshev, A., Gastaldo, L., Gavriljuk, Yu. M., Gezhaev, A., Grigoryeva, V. D., Gurentsov, V., Ha, D. H., Ha, C., Ha, E. J., Hahn, I., Jeon, E. J., Jeon, J., Jo, H. S., Kaewkhao, J., Kang, C. S., Kang, S. J., Kang, W. G., Karki, S., Kazalov, V., Khan, A., Khan, S., Kim, D. -Y., Kim, G. W., Kim, H. B., Kim, H. J., Kim, H. L., Kim, H. S., Kim, I., Kim, W. T., Kim, S., Kim, S. C., Kim, S. K., Kim, Y. D., Kim, Y. H., Kirdsiri, K., Ko, Y. J., Kobychev, V. V., Kornoukhov, V., Kuzminov, V., Kwon, D. H., Lee, C., Lee, E. K., Lee, H. J., Lee, H. S., Lee, J., Lee, J. S., Lee, J. Y., Lee, K. B., Lee, M. H., Lee, M. K., Lee, S. H., Lee, S. W., Leonard, D. S., Li, J., Li, Y., Limkitjaroenporn, P., Mailyan, B., Makarov, E. P., Oh, S. Y., Oh, Y. M., Gileva, O., Olsen, S., Pabitra, A., Panasenko, S., Pandey, I., Park, C. W., Park, H. K., Park, H. S., Park, K. S., Park, S. Y., Polischuk, O. G., Prihtiadi, H., Ra, S. J., Ratkevich, S., Rooh, G., Sari, M. B., Seo, J., Seo, K. M., Shin, J. W., Shin, K. A., Shlegel, V. N., Siyeon, K., Sokur, N. V., Son, J. -K., Srisittipokakun, N., Toibaev, N., Tretyak, V. I., Wirawan, R., Woo, K. R., Yoon, Y. S., and Yue, Q.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Advanced Mo-based Rare process Experiment (AMoRE)-Pilot experiment is an initial phase of the AMoRE search for neutrinoless double beta decay of $^{100}$Mo, with the purpose of investigating the level and sources of backgrounds. Searches for neutrinoless double beta decay generally require ultimately low backgrounds. Surface $\alpha$ decays on the crystals themselves or nearby materials can deposit a continuum of energies that can be as high as the $Q$-value of the decay itself and may fall in the region of interest (ROI). To understand these background events, we studied backgrounds from radioactive contaminations internal to and on the surface of the crystals or nearby materials with Geant4-based Monte Carlo simulations. In this study, we report on the measured $\alpha$ energy spectra fitted with the corresponding simulated spectra for six crystal detectors, where sources of background contributions could be identified through high energy $\alpha$ peaks and continuum parts in the energy spectrum for both internal and surface contaminations. We determine the low-energy contributions from internal and surface $\alpha$ contaminations by extrapolating from the $\alpha$ background fitting model.

Published
2021
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34. The environmental monitoring system at the COSINE-100 experiment

Author

Kim, H., Adhikari, G., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., França, L. E., Ha, C., Hahn, I. S., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, H. J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

The COSINE-100 experiment is designed to test the DAMA experiment which claimed an observation of a dark matter signal from an annual modulation in their residual event rate. To measure the 1 %-level signal amplitude, it is crucial to control and monitor nearly all environmental quantities that might systematically mimic the signal. The environmental monitoring also helps ensure a stable operation of the experiment. Here, we describe the design and performance of the centralized environmental monitoring system for the COSINE-100 experiment., Comment: 13 pages, 11 figures

Published
2021
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35. Measurement of the charge asymmetry of electrons from the decays of $W$ bosons produced in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

Author

CDF Collaboration, Aaltonen, T., Amerio, S., Amidei, D., Anastassov, A., Annovi, A., Antos, J., Apollinari, G., Appel, J. A., Arisawa, T., Artikov, A., Asaadi, J., Ashmanskas, W., Auerbach, B., Aurisano, A., Azfar, F., Badgett, W., Bae, T., Barbaro-Galtieri, A., Barnes, V. E., Barnett, B. A., Barria, P., Bartos, P., Bauce, M., Bedeschi, F., Behari, S., Bellettini, G., Bellinger, J., Benjamin, D., Beretvas, A., Bhatti, A., Bland, K. R., Blumenfeld, B., Bocci, A., Bodek, A., Bortoletto, D., Boudreau, J., Boveia, A., Brigliadori, L., Bromberg, C., Brucken, E., Budagov, J., Budd, H. S., Burkett, K., Busetto, G., Bussey, P., Butti, P., Buzatu, A., Calamba, A., Camarda, S., Campanelli, M., Canelli, F., Carls, B., Carlsmith, D., Carosi, R., Carrillo, S., Casal, B., Casarsa, M., Castro, A., Catastini, P., Cauz, D., Cavaliere, V., Cerri, A., Cerrito, L., Chen, Y. C., Chertok, M., Chiarelli, G., Chlachidze, G., Cho, K., Chokheli, D., Clark, A., Clarke, C., Convery, M. E., Conway, J., Corbo, M., Cordelli, M., Cox, C. A., Cox, D. J., Cremonesi, M., Cruz, D., Cuevas, J., Culbertson, R., d'Ascenzo, N., Datta, M., de Barbaro, P., Demortier, L., Deninno, M., D'Errico, M., Devoto, F., Di Canto, A., Di Ruzza, B., Dittmann, J. R., Donati, S., D'Onofrio, M., Dorigo, M., Driutti, A., Ebina, K., Edgar, R., Elagin, A., Erbacher, R., Errede, S., Esham, B., Farrington, S., Ramos, J. P. Fernández, Field, R., Flanagan, G., Forrest, R., Franklin, M., Freeman, J. C., Frisch, H., Funakoshi, Y., Galloni, C., Garfinkel, A. F., Garosi, P., Gerberich, H., Gerchtein, E., Giagu, S., Giakoumopoulou, V., Gibson, K., Ginsburg, C. M., Giokaris, N., Giromini, P., Glagolev, V., Glenzinski, D., Gold, M., Goldin, D., Golossanov, A., Gomez, G., Gomez-Ceballos, G., Goncharov, M., López, O. González, Gorelov, I., Goshaw, A. T., Goulianos, K., Gramellini, E., Grosso-Pilcher, C., da Costa, J. Guimaraes, Hahn, S. R., Han, J. Y., Happacher, F., Hara, K., Hare, M., Harr, R. F., Harrington-Taber, T., Hatakeyama, K., Hays, C., Heinrich, J., Herndon, M., Hocker, A., Hong, Z., Hopkins, W., Hou, S., Hughes, R. E., Husemann, U., Hussein, M., Huston, J., Introzzi, G., Iori, M., Isgrò, A., Ivanov, A., James, E., Jang, D., Jayatilaka, B., Jeon, E. J., Jindariani, S., Jones, M., Joo, K. K., Jun, S. Y., Junk, T. R., Kambeitz, M., Kamon, T., Karchin, P. E., Kasmi, A., Kato, Y., Ketchum, W., Keung, J., Kilminster, B., Kim, D. H., Kim, H. S., Kim, J. E., Kim, M. J., Kim, S. H., Kim, S. B., Kim, Y. J., Kim, Y. K., Kimura, N., Kirby, M., Kondo, K., Kong, D. J., Konigsberg, J., Kotwal, A. V., Kreps, M., Kroll, J., Kruse, M., Kuhr, T., Kurata, M., Laasanen, A. T., Lammel, S., Lancaster, M., Lannon, K., Latino, G., Lee, H. S., Lee, J. S., Leo, S., Leone, S., Lewis, J. D., Limosani, A., Lipeles, E., Lister, A., Liu, Q., Liu, T., Lockwitz, S., Loginov, A., Lucchesi, D., Lucà, A., Lueck, J., Lujan, P., Lukens, P., Lungu, G., Lys, J., Lysak, R., Madrak, R., Maestro, P., Malik, S., Manca, G., Manousakis-Katsikakis, A., Marchese, L., Margaroli, F., Marino, P., Matera, K., Mattson, M. E., Mazzacane, A., Mazzanti, P., McNulty, R., Mehta, A., Mehtala, P., Mesropian, C., Miao, T., Michielin, E., Mietlicki, D., Mitra, A., Miyake, H., Moed, S., Moggi, N., Moon, C. S., Moore, R., Morello, M. J., Mukherjee, A., Muller, Th., Murat, P., Mussini, M., Nachtman, J., Nagai, Y., Naganoma, J., Nakano, I., Napier, A., Nett, J., Nigmanov, T., Nodulman, L., Noh, S. Y., Norniella, O., Oakes, L., Oh, S. H., Oh, Y. D., Okusawa, T., Orava, R., Ortolan, L., Pagliarone, C., Palencia, E., Palni, P., Papadimitriou, V., Parker, W., Pauletta, G., Paulini, M., Paus, C., Phillips, T. J., Piacentino, G., Pianori, E., Pilot, J., Pitts, K., Plager, C., Pondrom, L., Poprocki, S., Potamianos, K., Pranko, A., Prokoshin, F., Ptohos, F., Punzi, G., Fernández, I. Redondo, Renton, P., Rescigno, M., Rimondi, F., Ristori, L., Robson, A., Rodriguez, T., Rolli, S., Ronzani, M., Roser, R., Rosner, J. L., Ruffini, F., Ruiz, A., Russ, J., Rusu, V., Sakumoto, W. K., Sakurai, Y., Santi, L., Sato, K., Saveliev, V., Savoy-Navarro, A., Schlabach, P., Schmidt, E. E., Schwarz, T., Scodellaro, L., Scuri, F., Seidel, S., Seiya, Y., Semenov, A., Sforza, F., Shalhout, S. Z., Shears, T., Shepard, P. F., Shimojima, M., Shochet, M., Shreyber-Tecker, I., Simonenko, A., Sliwa, K., Smith, J. R., Snider, F. D., Song, H., Sorin, V., Denis, R. St., Stancari, M., Stentz, D., Strologas, J., Sudo, Y., Sukhanov, A., Suslov, I., Takemasa, K., Takeuchi, Y., Tang, J., Tecchio, M., Teng, P. K., Thom, J., Thomson, E., Thukral, V., Toback, D., Tokar, S., Tollefson, K., Tomura, T., Tonelli, D., Torre, S., Torretta, D., Totaro, P., Trovato, M., Ukegawa, F., Uozumi, S., Vecchio, V., Velev, G., Vellidis, C., Vernieri, C., Vidal, M., Vilar, R., Vizán, J., Vogel, M., Volpi, G., Vázquez, F., Wagner, P., Wallny, R., Wang, S. M., Waters, D., Wester III, W. C., Whiteson, D., Wicklund, A. B., Wilbur, S., Williams, H. H., Wilson, J. S., Wilson, P., Winer, B. L., Wittich, P., Wolbers, S., Wolfmeister, H., Wright, T., Wu, X., Wu, Z., Yamamoto, K., Yamato, D., Yang, T., Yang, U. K., Yang, Y. C., Yao, W. -M., Yeh, G. P., Yi, K., Yoh, J., Yorita, K., Yoshida, T., Yu, G. B., Yu, I., Zanetti, A. M., Zeng, Y., Zhou, C., and Zucchelli, S.

Subjects
High Energy Physics - Experiment
Abstract

At the Fermilab Tevatron proton-antiproton ($p\bar{p}$) collider, high-mass electron-neutrino ($e\nu$) pairs are produced predominantly in the process $p \bar{p} \rightarrow W(\rightarrow e\nu) + X$. The asymmetry of the electron and positron yield as a function of their pseudorapidity constrain the slope of the ratio of the $u$- to $d$-quark parton distributions versus the fraction of the proton momentum carried by the quarks. This paper reports on the measurement of the electron-charge asymmetry using the full data set recorded by the Collider Detector at Fermilab in 2001--2011 and corresponding to 9.1~fb$^{-1}$ of integrated luminosity. The measurement significantly improves the precision of the Tevatron constraints on the parton-distribution functions of the proton. Numerical tables of the measurement are provided., Comment: 27 pages, 25 figures. To be published in PRD

Published
2021

36. Strong constraints from COSINE-100 on the DAMA dark matter results using the same sodium iodide target

Author

Adhikari, G., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., França, L. E., Ha, C., Hahn, I. S., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, H., Kim, H. J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scar, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present new constraints on dark matter interactions using 1.7 years of COSINE-100 data. The COSINE-100 experiment, consisting of 106 kg of tallium-doped sodium iodide (NaI(Tl)) target material, is aimed at testing DAMA's claim of dark matter observation using the same NaI(Tl) detectors. Improved event selection requirements, a more precise understanding of the detector background and the use of a larger data set considerably enhances the COSINE-100 sensitivity for dark matter detection. No signal consistent with the dark matter interaction is identified, and rules out model-dependent dark matter interpretations of the DAMA signals in the specific context of standard halo model with the same NaI(Tl) target for various interaction hypotheses.

Published
2021
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37. Probing the Symmetry Energy with the Spectral Pion Ratio

Author

Estee, J., Lynch, W. G., Tsang, C. Y., Barney, J., Jhang, G., Tsang, M. B., Wang, R., Kaneko, M., Lee, J. W., Isobe, T., Kurata-Nishimura, M., Murakami, T., Ahn, D. S., Atar, L., Aumann, T., Baba, H., Boretzky, K., Brzychczyk, J., Cerizza, G., Chiga, N., Fukuda, N., Gasparic, I., Hong, B., Horvat, A., Ieki, K., Inabe, N., Kim, Y. J., Kobayashi, T., Kondo, Y., Lasko, P., Lee, H. S., Leifels, Y., Łukasik, J., Manfredi, J., McIntosh, A. B., Morfouace, P., Nakamura, T., Nakatsuka, N., Nishimura, S., Otsu, H., Pawłowski, P., Pelczar, K., Rossi, D., Sakurai, H., Santamaria, C., Sato, H., Scheit, H., Shane, R., Shimizu, Y., Simon, H., Snoch, A., Sochocka, A., Sumikama, T., Suzuki, H., Suzuki, D., Takeda, H., Tangwancharoen, S., Toernqvist, H., Togano, Y., Xiao, Z. G., Yennello, S. J., Zhang, Y., and Cozma, M. D.

Subjects
Nuclear Experiment
Abstract

Many neutron star (NS) properties, such as the proton fraction within a NS, reflect the symmetry energy contributions to the Equation of State that dominate when neutron and proton densities differ strongly. To constrain these contributions at supra-saturation densities, we measure the spectra of charged pions produced by colliding rare isotope tin (Sn) beams with isotopically enriched Sn targets. Using ratios of the charged pion spectra measured at high transverse momenta, we deduce the slope of the symmetry energy to be $42 < L < 117$ MeV. This value is slightly lower but consistent with the $L$ values deduced from a recent measurement of the neutron skin thickness of $^{208}$Pb.

Published
2021
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38. Identification of new isomers in $^{228}$Ac : Impact on dark matter searches

Author

Kim, K. W., Adhikari, G., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Jeon, E. J., Jo, J. H., Joo, H. W., Kang, W. G., Kauer, M., Kim, H., Kim, H. J., Kim, S. H., Kim, S. K., Kim, W. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. M., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

We report the identification of metastable isomeric states of $^{228}$Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the $\beta$-decay of $^{228}$Ra, a component of the $^{232}$Th decay chain, with $\beta$ Q-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to its low Q-value as well as the relative abundance of $^{232}$Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments., Comment: 9 pages, 9 figures

Published
2021
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39. Background modeling for dark matter search with 1.7 years of COSINE-100 data

Author

Adhikari, G., Adhikari, P., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Jeon, E. J., Jo, J. H., Kang, W. G., Kauer, M., Kim, G. S., Kim, H., Kim, H. J., Kim, K. W., Kim, N. Y., Kim, S. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Kudryavtsev, V. A., Lee, E. K., Lee, H. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Leonard, D. S., Lynch, W. A., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, H. K., Park, H. S., Park, K. S., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We present a background model for dark matter searches using an array of NaI(Tl) crystals in the COSINE-100 experiment that is located in the Yangyang underground laboratory. The model includes background contributions from both internal and external sources, including cosmogenic radionuclides and surface $^{210}$Pb contamination. To build the model in the low energy region, with a threshold of 1 keV, we used a depth profile of $^{210}$Pb contamination in the surface of the NaI(Tl) crystals determined in a comparison between measured and simulated spectra. We also considered the effect of the energy scale errors propagated from the statistical uncertainties and the nonlinear detector response at low energies. The 1.7 years COSINE-100 data taken between October 21, 2016 and July 18, 2018 were used for this analysis. Our Monte Carlo simulation provides a non-Gaussian peak around 50 keV originating from beta decays of bulk $^{210}$Pb in a good agreement with the measured background. This model estimates that the activities of bulk $^{210}$Pb and $^{3}$H are dominating the background rate that amounts to an average level of 2.85$\pm$0.15 counts/day/keV/kg in the energy region of (1-6) keV, using COSINE-100 data with a total exposure of 97.7 kg$\cdot$years.

Published
2021
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40. Symmetry energy investigation with pion production from Sn+Sn systems

Author

Jhang, G., Estee, J., Barney, J., Cerizza, G., Kaneko, M., Lee, J. W., Lynch, W. G., Isobe, T., Kurata-Nishimura, M., Murakami, T., Tsang, C. Y ., Tsang, M. B., Wang, R., Ahn, D. S., Atar, L., Aumann, T., Baba, H., Boretzky, K., Brzychczyk, J., Chiga, N., Fukuda, N., Gasparic, I., Hong, B., Horvat, A., Ieki, K., Inabe, N., Kim, Y. J., Kobayashi, T., Kondo, Y., Lasko, P., Lee, H. S., Leifels, Y., Łukasik, J., Manfredi, J., McIntosh, A. B., Morfouace, P., Nakamura, T., Nakatsuka, N., Nishimura, S., Olsen, R., Otsu, H., Pawłowski, P., Pelczar, K., Rossi, D., Sakurai, H., Santamaria, C., Sato, H., Scheit, H., Shane, R., Shimizu, Y., Simon, H., Snoch, A., Sochocka, A., Sosin, Z., Sumikama, T., Suzuki, H., Suzuki, D., Takeda, H., Tangwancharoen, S., Toernqvist, H., Togano, Y., Xiao, Z. G., Yennello, S. J., Yurkon, J., Zhang, Y., Colonna, Maria, Cozma, Dan, Danielewicz, Paweł, Elfner, Hannah, Ikeno, Natsumi, Ko, Che Ming, Mohs, Justin, Oliinychenko, Dmytro, Ono, Akira, Su, Jun, Wang, Yong Jia, Wolter, Hermann, Xu, Jun, Zhang, Ying-Xun, and Zhang, Zhen

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

In the past two decades, pions created in the high density regions of heavy ion collisions have been predicted to be sensitive at high densities to the symmetry energy term in the nuclear equation of state, a property that is key to our understanding of neutron stars. In a new experiment designed to study the symmetry energy, the multiplicities of negatively and positively charged pions have been measured with high accuracy for central $^{132}$Sn+$^{124}$Sn, $^{112}$Sn+$^{124}$Sn, and $^{108}$Sn+$^{112}$Sn collisions at $E/A=270~\mathrm{MeV}$ with the S$\pi$RIT Time Projection Chamber. While the uncertainties of individual pion multiplicities are measured to 4\%, those of the charged pion multiplicity ratios are measured to 2\%. We compare these data to predictions from seven major transport models. The calculations reproduce qualitatively the dependence of the multiplicities and their ratios on the total neutron to proton number in the colliding systems. However, the predictions of the transport models from different codes differ too much to allow extraction of reliable constraints on the symmetry energy from the data. This finding may explain previous contradictory conclusions on symmetry energy constraints obtained from pion data in Au+Au system. These new results call for better understanding of the differences among transport codes, and new observables that are more sensitive to the density dependence of the symmetry energy., Comment: 8 pages, 4 figures, 1 table (accepted for publication in PLB)

Published
2020
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41. Comparison of $pp$ and $p \bar{p}$ differential elastic cross sections and observation of the exchange of a colorless $C$-odd gluonic compound

Author

Abazov, V. M., Abbott, B., Acharya, B. S., Adams, M., Adams, T., Agnew, J. P., Alexeev, G. D., Alkhazov, G., Alton, A., Alves, G. A., Antchev, G., Askew, A., Aspell, P., Jesus, A. C. S. Assis, Atanassov, I., Atkins, S., Augsten, K., Aushev, V., Aushev, Y., Avati, V., Avila, C., Badaud, F., Baechler, J., Bagby, L., Barrera, C. Baldenegro, Baldin, B., Bandurin, D. V., Banerjee, S., Barberis, E., Baringer, P., Barreto, J., Bartlett, J. F., Bassler, U., Bazterra, V., Bean, A., Begalli, M., Bellantoni, L., Berardi, V., Beri, S. B., Bernardi, G., Bernhard, R., Berretti, M., Bertram, I., Besanccon, M., Beuselinck, R., Bhat, P. C., Bhatia, S., Bhatnagar, V., Blazey, G., Blessing, S., Bloom, K., Boehnlein, A., Boline, D., Boos, E. E., Borchsh, V., Borissov, G., Borysova, M., Bossini, E., Bottigli, U., Bozzo, M., Brandt, A., Brandt, O., Brochmann, M., Brock, R., Bross, A., Brown, D., Bu, X. B., Buehler, M., Buescher, V., Bunichev, V., Burdin, S., Burkhardt, H., Buszello, C. P., Cafagna, F. S., Camacho-P'erez, E., Carvahlo, W., Casey, B. C. K., Castilla-Valdez, H., Catanesi, M. G., Caughron, S., Chakrabarti, S., Chan, K. M., Chandra, A., Chapon, E., Chen, G., Cho, S. W., Choi, S., Choudhary, B., Cihangir, S., Claes, D., Clutter, J., Cooke, M., Cooper, W. E., Corcoran, M., Couderc, F., Cousinou, M. -C., Csan'ad, M., Cs"orgHo, T., Cuth, J., Cutts, D., Das, A., Davies, G., Deile, M., de Jong, S. J., De La Cruz-Burelo, E., De Leonardis, F., D'eliot, F., Demina, R., Denisov, D., Denisov, S. P., Desai, S., Deterre, C., DeVaughan, K., Diehl, H. T., Diesburg, M., Ding, P. F., Dominguez, A., Doubek, M., Drutskoy, A., Druzhkin, D., Dubey, A., Dudko, L. V., Duperrin, A., Dutt, S., Eads, M., Edmunds, D., Eggert, K., Ellison, J., Elvira, V. D., Enari, Y., Eremin, V., Evans, H., Evdokimov, A., Evdokimov, V. N., Faur'e, A., Feng, L., Ferbel, T., Ferro, F., Fiedler, F., Fiergolski, A., Filthaut, F., Fisher, W., Fisk, H. E., Forthomme, L., Fortner, M., Fox, H., Franc, J., Fuess, S., Garbincius, P. H., Garcia, F., Garcia-Bellido, A., Garc'ia-Gonz'alez, J. A., Gavrilov, V., Geng, W., Georgiev, V., Gerber, C. E., Gershtein, Y., Giani, S., Ginther, G., Gogota, O., Golovanov, G., Grannis, P. D., Greder, S., Greenlee, H., Grenier, G., Gris, Ph., Grivaz, J. -F., Grohsjean, A., Gr"unendahl, S., Gr"unewald, M. W., Grzanka, L., Guillemin, T., Gutierrez, G., Gutierrez, P., Haley, J., Hammerbauer, J., Han, L., Harder, K., Harel, A., Hauptman, J. M., Hays, J., Head, T., Hebbeker, T., Hedin, D., Hegab, H., Heinson, A. P., Heintz, U., Hensel, C., La Cruz, I. Heredia-De, Herner, K., Hesketh, G., Hildreth, M. D., Hirosky, R., Hoang, T., Hobbs, J. D., Hoeneisen, B., Hogan, J., Hohlfeld, M., Holzbauer, J. L., Howley, I., Hubacek, Z., Hynek, V., Iashvili, I., Ilchenko, Y., Illingworth, R., Isidori, T., Ito, A. S., Ivanchenko, V., Jabeen, S., Jaffr'e, M., Janda, M., Jayasinghe, A., Jeong, M. S., Jesik, R., Jiang, P., Johns, K., Johnson, E., Johnson, M., Jonckheere, A., Jonsson, P., Joshi, J., Jung, A. W., Juste, A., Kajfasz, E., Karev, A., Karmanov, D., Kavspar, J., Katsanos, I., Kaur, M., Kaynak, B., Kehoe, R., Kermiche, S., Khalatyan, N., Khanov, A., Kharchilava, A., Kharzheev, Y. N., Kiselevich, I., Kohli, J. M., Kopal, J., Kozelov, A. V., Kraus, J., Kumar, A., Kundr'at, V., Kupco, A., Kurvca, T., Kuzmin, V. A., Lami, S., Lammers, S., Latino, G., Lebrun, P., Lee, H. S., Lee, S. W., Lee, W. M., Le, X., Lellouch, J., Li, D., Li, H., Li, L., Li, Q. Z., Lim, J. K., Lincoln, D., Lindsey, C., Linhart, R., Linnemann, J., Lipaev, V. V., Lipton, R., Liu, H., Liu, Y., Lobodenko, A., Lokajicek, M., Lokaj'ivcek, M. V., de Sa, R. Lopes, Losurdo, L., Rodr'iguez, F. Lucas, Luna-Garcia, R., Lyon, A. L., Maciel, A. K. A., Macr'i, M., Madar, R., na-Villalba, R. Maga, Malawski, M., Malbouisson, H. B., Malik, S., Malyshev, V. L., Mansour, J., Mart'inez-Ortega, J., McCarthy, R., McGivern, C. L., Meijer, M. M., Melnitchouk, A., Menezes, D., Mercadante, P. G., Merkin, M., Meyer, A., Meyer, J., Miconi, F., Minafra, N., Minutoli, S., Molina, J., Mondal, N. K., Da Motta, H., Mulhearn, M., Mundim, L., Naaranoja, T., Nagy, E., Narain, M., Nayyar, R., Neal, H. A., Negret, J. P., Nemes, F., Neustroev, P., Nguyen, H. T., Niewiadomski, H., Nov'ak, T., Nunnemann, T., Oguri, V., Oliveri, E., Oljemark, F., Orduna, J., Oriunno, M., Osman, N., "Osterberg, K., Pal, A., Palazzi, P., Parashar, N., Parihar, V., Park, S. K., Partridge, R., Parua, N., Pasechnik, R., Passaro, V., Patwa, A., Penning, B., Perfilov, M., Peroutka, Z., Peters, Y., Petridis, K., Petrillo, G., P'etroff, P., Pleier, M. -A., Podstavkov, V. M., Popov, A. V., Da Silva, W. L. Prado, Prewitt, M., Price, D., Proch'azka, J., Prokopenko, N., Qian, J., Quadt, A., Quinn, B., Quinto, M., Raben, T. G., Radermacher, E., Rangel, M., Radicioni, E., Ratoff, P. N., Ravotti, F., Razumov, I., Ripp-Baudot, I., Rizatdinova, F., Robutti, E., Rodrigues, R. F., Rominsky, M., Ross, A., Royon, C., Rubinov, P., Ruchti, R., Ruggiero, G., Saarikko, H., Sajot, G., Samoylenko, V. D., S'anchez-Hern'andez, A., Sanders, M. P., Santoro, A., Santos, A. S., Savage, G., Savitskyi, M., Sawyer, L., Scanlon, T., Schamberger, R. D., Scheglov, Y., Schellman, H., Schott, M., Schwanenberger, C., Schwienhorst, R., Scribano, A., Sekaric, J., Severini, H., Shabalina, E., Shary, V., Shaw, S., Shchukin, A. A., Shkola, O., Simak, V., Siroky, J., Skubic, P., Slattery, P., Smajek, J., Snoeys, W., Snow, G. R., Snow, J., Snyder, S., S"oldner-Rembold, S., Sonnenschein, L., Soustruznik, K., Stark, J., Stefaniuk, N., Stefanovitch, R., Ster, A., Stoyanova, D. A., Strauss, M., Suter, L., Svoisky, P., Szanyi, I., Sziklai, J., Taylor, C., Tcherniaev, E., Titov, M., Tokmenin, V. V., Tsai, Y. -T., Tsybychev, D., Tuchming, B., Tully, C., Turini, N., Urban, O., Uvarov, L., Uvarov, S., Uzunyan, S., Vacek, V., Van Kooten, R., van Leeuwen, W. M., Varelas, N., Varnes, E. W., Vasilyev, I. A., Vavroch, O., Verkheev, A. Y., Vertogradov, L. S., Verzocchi, M., Vesterinen, M., Vilanova, D., Vokac, P., Wahl, H. D., Wang, C., Wang, M. H. L. S., Warchol, J., Watts, G., Wayne, M., Weichert, J., Welti, J., Welty-Rieger, L., Williams, J., Williams, M. R. J., Wilson, G. W., Wobisch, M., Wood, D. R., Wyatt, T. R., Xie, Y., Yamada, R., Yang, S., Yasuda, T., Yatsunenko, Y. A., Ye, W., Ye, Z., Yin, H., Yip, K., Youn, S. W., Yu, J. M., Zennamo, J., Zhao, T. G., Zhou, B., Zhu, J., Zich, J., Zielinski, K., Zielinski, M., Zieminska, D., and Zivkovic, L.

Subjects
High Energy Physics - Experiment
Abstract

We describe an analysis comparing the $p\bar{p}$ elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that in $pp$ collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13 TeV using a model-independent approach. The TOTEM cross sections extrapolated to a center-of-mass energy of $\sqrt{s} =$ 1.96 TeV are compared with the D0 measurement in the region of the diffractive minimum and the second maximum of the $pp$ cross section. The two data sets disagree at the 3.4$\sigma$ level and thus provide evidence for the $t$-channel exchange of a colorless, $C$-odd gluonic compound, also known as the odderon. We combine these results with a TOTEM analysis of the same $C$-odd exchange based on the total cross section and the ratio of the real to imaginary parts of the forward elastic scattering amplitude in $pp$ scattering. The combined significance of these results is larger than 5$\sigma$ and is interpreted as the first observation of the exchange of a colorless, $C$-odd gluonic compound., Comment: D0 and TOTEM Collaborations

Published
2020
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43. Improving the light collection using a new NaI(Tl)crystal encapsulation

Author

Choi, J. J., Park, B. J., Ha, C., Kim, K. W., Kim, S. K., Kim, Y. D., Ko, Y. J., Lee, H. S., Lee, S. H., and Olsen, S. L.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment
Abstract

NaI(Tl) crystals are used as particle detectors in a variety of rare-event search experiments because of their superb light-emission quality. The crystal light yield is generally high, above 10 photoelectrons per keV, and its emission spectrum is peaked around 400 nm, which matches well to the sensitive region of bialkali photocathode photomultiplier tubes. However, since NaI(Tl) crystals are hygroscopic, a sophisticated method of encapsulation has to be applied that prevents moisture from chemically attacking the crystal and thereby degrading the emission. In addition, operation with low energy thresholds, which is essential for a number of new phenomenon searches, is usually limited by the crystal light yield; in these cases higher light yields can translate into lower thresholds that improve the experimental sensitivity. Here we describe the development of an encapsulation technique that simplifies the overall design by attaching the photo sensors directly to the crystal so that light losses are minimized. The light yield of a NaI(Tl) crystal encapsulated with this technique was improved by more than 30%, and as many as 22 photoelectrons per keV have been measured. Consequently, the energy threshold can be lowered and the energy resolution improved. Detectors with this higher light yield are sensitive to events with sub-keV energies and well suited for low-mass dark matter particle searches and measurements of neutrino-nucleus coherent scattering., Comment: 15 pages, 7 figures (minor edits)

Published
2020

44. The LUX-ZEPLIN (LZ) radioactivity and cleanliness control programs

Author

Akerib, D. S., Akerlof, C. W., Akimov, D. Yu., Alquahtani, A., Alsum, S. K., Anderson, T. J., Angelides, N., Araújo, H. M., Arbuckle, A., Armstrong, J. E., Arthurs, M., Auyeung, H., Aviles, S., Bai, X., Bailey, A. J., Balajthy, J., Balashov, S., Bang, J., Barry, M. J., Bauer, D., Bauer, P., Baxter, A., Belle, J., Beltrame, P., Bensinger, J., Benson, T., Bernard, E. P., Bernstein, A., Bhatti, A., Biekert, A., Biesiadzinski, T. P., Birch, H. J., Birrittella, B., Boast, K. E., Bolozdynya, A. I., Boulton, E. M., Boxer, B., Bramante, R., Branson, S., Brás, P., Breidenbach, M., Brew, C. A. J., Buckley, J. H., Bugaev, V. V., Bunker, R., Burdin, S., Busenitz, J. K., Cabrita, R., Campbell, J. S., Carels, C., Carlsmith, D. L., Carlson, B., Carmona-Benitez, M. C., Cascella, M., Chan, C., Cherwinka, J. J., Chiller, A. A., Chiller, C., Chott, N. I., Cole, A., Coleman, J., Colling, D., Conley, R. A., Cottle, A., Coughlen, R., Cox, G., Craddock, W. W., Curran, D., Currie, A., Cutter, J. E., da Cunhaw, J. P., Dahl, C. E., Dardin, S., Dasu, S., Davis, J., Davison, T. J. R., de Viveiros, L., Decheine, N., Dobi, A., Dobson, J. E. Y., Druszkiewicz, E., Dushkin, A., Edberg, T. K., Edwards, W. R., Edwards, B. N., Edwards, J., Elnimr, M. M., Emmet, W. T., Eriksen, S. R., Faham, C. H., Fan, A., Fayer, S., Fiorucci, S., Flaecher, H., Florang, I. M. Fogarty, Ford, P., Francis, V. B., Fraser, E. D., Froborg, F., Fruth, T., Gaitskell, R. J., Gantos, N. J., Garcia, D., Gehman, V. M., Gelfand, R., Genovesi, J., Gerhard, R. M., Ghag, C., Gibson, E., Gilchriese, M. G. D., Gokhale, S., Gomber, B., Gonda, T. G., Greenall, A., Greenwood, S., Gregerson, G., van der Grinten, M. G. D., Gwilliam, C. B., Hall, C. R., Hamilton, D., Hans, S., Hanzel, K., Harrington, T., Harrison, A., Harrison, J., Hasselkus, C., Haselschwardt, S. J., Hemer, D., Hertel, S. A., Heise, J., Hillbrand, S., Hitchcock, O., Hjemfelt, C., Hoff, M. D., Holbrook, B., Holtom, E., Hor, J. Y-K., Horn, M., Huang, D. Q., Hurteau, T. W., Ignarra, C. M., Irving, M. N., Jacobsen, R. G., Jahangir, O., Jeffery, S. N., Ji, W., Johnson, M., Johnson, J., Johnson, P., Jones, W. G., Kaboth, A. C., Kamaha, A., Kamdin, K., Kasey, V., Kazkaz, K., Keefner, J., Khaitan, D., Khaleeq, M., Khazov, A., Khromov, A. V., Khurana, I., Kim, Y. D., Kim, W. T., Kocher, C. D., Kodroff, D., Konovalov, A. M., Korley, L., Korolkova, E. V., Koyuncu, M., Kras, J., Kraus, H., Kravitz, S. W., Krebs, H. J., Kreczko, L., Krikler, B., Kudryavtsev, V. A., Kumpan, A. V., Kyre, S., Lambert, A. R., Landerud, B., Larsen, N. A., Laundrie, A., Leason, E. A., Lee, H. S., Lee, J., Lee, C., Lenardo, B. G., Leonard, D. S., Leonard, R., Lesko, K. T., Levy, C., Li, J., Liu, Y., Liao, J., Liao, F. -T., Lin, J., Lindote, A., Linehan, R., Lippincott, W. H., Liu, R., Liu, X., Loniewski, C., Lopes, M. I., Lopez-Asamar, E., Paredes, B. López, Lorenzon, W., Lucero, D., Luitz, S., Lyle, J. M., Lynch, C., Majewski, P. A., Makkinje, J., Malling, D. C., Manalaysay, A., Manenti, L., Mannino, R. L., Marangou, N., Markley, D. J., MarrLaundrie, P., Martin, T. J., Marzioni, M. F., Maupin, C., McConnell, C. T., McKinsey, D. N., McLaughlin, J., Mei, D. -M., Meng, Y., Miller, E. H., Minaker, Z. J., Mizrachi, E., Mock, J., Molash, D., Monte, A., Monzani, M. E., Morad, J. A., Morrison, E., Mount, B. J., Murphy, A. St. J., Naim, D., Naylor, A., Nedlik, C., Nehrkorn, C., Nelson, H. N., Nesbit, J., Neves, F., Nikkel, J. A., Nikoleyczik, J. A., Nilima, A., O'Dell, J., Oh, H., O'Neill, F. G., O'Sullivan, K., Olcina, I., Olevitch, M. A., Oliver-Mallory, K. C., Oxborough, L., Pagac, A., Pagenkopf, D., Pal, S., Palladino, K. J., Palmaccio, V. M., Palmer, J., Pangilinan, M., Parveen, N., Patton, S. J., Pease, E. K., Penning, B. P., Pereira, G., Pereira, C., Peterson, I. B., Piepke, A., Pierson, S., Powell, S., Preece, R. M., Pushkin, K., Qie, Y., Racine, M., Ratcliff, B. N., Reichenbacher, J., Reichhart, L., Rhyne, C. A., Richards, A., Riffard, Q., Rischbieter, G. R. C., Rodrigues, J. P., Rose, H. J., Rosero, R., Rossiter, P., Rucinski, R., Rutherford, G., Saba, J. S., Sabarots, L., Santone, D., Sarychev, M., Sazzad, A. B. M. R., Schnee, R. W., Schubnell, M., Scovell, P. R., Severson, M., Seymour, D., Shaw, S., Shutt, G. W., Shutt, T. A., Silk, J. J., Silva, C., Skarpaas, K., Skulski, W., Smith, A. R., Smith, R. J., Smith, R. E., So, J., Solmaz, M., Solovov, V. N., Sorensen, P., Sosnovtsev, V. V., Stancu, I., Stark, M. R., Stephenson, S., Stern, N., Stevens, A., Stiegler, T. M., Stifter, K., Studley, R., Sumner, T. J., Sundarnath, K., Sutcliffe, P., Swanson, N., Szydagis, M., Tan, M., Taylor, W. C., Taylor, R., Taylor, D. J., Temples, D., Tennyson, B. P., Terman, P. A., Thomas, K. J., Thomson, J. A., Tiedt, D. R., Timalsina, M., To, W. H., Tomás, A., Tope, T. E., Tripathi, M., Tronstad, D. R., Tull, C. E., Turner, W., Tvrznikova, L., Utes, M., Utku, U., Uvarov, S., Va'vra, J., Vacheret, A., Vaitkus, A., Verbus, J. R., Vietanen, T., Voirin, E., Vuosalo, C. O., Walcott, S., Waldron, W. L., Walker, K., Wang, J. J., Wang, R., Wang, L., Wang, W., Wang, Y., Watson, J. R., Migneault, J., Weatherly, S., Webb, R. C., Wei, W. -Z., While, M., White, R. G., White, J. T., White, D. T., Whitis, T. J., Wisniewski, W. J., Wilson, K., Witherell, M. S., Wolfs, F. L. H., Wolfs, J. D., Woodward, D., Worm, S. D., Xiang, X., Xiao, Q., Xu, J., Yeh, M., Yin, J., Young, I., Zhang, C., and Zarzhitsky, P.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

LUX-ZEPLIN (LZ) is a second-generation direct dark matter experiment with spin-independent WIMP-nucleon scattering sensitivity above $1.4 \times 10^{-48}$ cm$^{2}$ for a WIMP mass of 40 GeV/c$^{2}$ and a 1000 d exposure. LZ achieves this sensitivity through a combination of a large 5.6 t fiducial volume, active inner and outer veto systems, and radio-pure construction using materials with inherently low radioactivity content. The LZ collaboration performed an extensive radioassay campaign over a period of six years to inform material selection for construction and provide an input to the experimental background model against which any possible signal excess may be evaluated. The campaign and its results are described in this paper. We present assays of dust and radon daughters depositing on the surface of components as well as cleanliness controls necessary to maintain background expectations through detector construction and assembly. Finally, examples from the campaign to highlight fixed contaminant radioassays for the LZ photomultiplier tubes, quality control and quality assurance procedures through fabrication, radon emanation measurements of major sub-systems, and bespoke detector systems to assay scintillator are presented., Comment: 45 pages (79 inc. tables), 7 figures, 9 tables

Published
2020
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45. Lowering the energy threshold in COSINE-100 dark matter searches

Author

Adhikari, G., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Jeon, E. J., Jo, J. H., Kang, W. G., Kauer, M., Kim, H., Kim, H. J., Kim, K. W., Kim, S. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, E. K., Lee, H. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

COSINE-100 is a dark matter detection experiment that uses NaI(Tl) crystal detectors operating at the Yangyang underground laboratory in Korea since September 2016. Its main goal is to test the annual modulation observed by the DAMA/LIBRA experiment with the same target medium. Recently DAMA/LIBRA has released data with an energy threshold lowered to 1 keV, and the persistent annual modulation behavior is still observed at 9.5$\sigma$. By lowering the energy threshold for electron recoils to 1 keV, COSINE-100 annual modulation results can be compared to those of DAMA/LIBRA in a model-independent way. Additionally, the event selection methods provide an access to a few to sub-GeV dark matter particles using constant rate studies. In this article, we discuss the COSINE-100 event selection algorithm, its validation, and efficiencies near the threshold.

Published
2020
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46. Measurement of the cosmic muon annual and diurnal flux variation with the COSINE-100 detector

Author

Collaboration, COSINE-100, Prihtiadi, H., Adhikari, G., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., França, L. E., Ha, C., Hahn, I. S., Jeon, E. J., Jo, J. H., Kang, W. G., Kauer, M., Kim, H., Kim, H. J., Kim, K. W., Kim, S. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, E. K., Lee, H. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Pitta, R. L. C., Ra, S. J., Rott, C., Shin, K. A., Scraff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We report measurements of annual and diurnal modulations of the cosmic-ray muon rate in the Yangyang underground laboratory (Y2L) using 952 days of COSINE-100 data acquired between September 2016 and July 2019. A correlation of the muon rate with the atmospheric temperature is observed and its amplitude on the muon rate is determined. The effective atmospheric temperature and muon rate variations are positively correlated with a measured effective temperature coefficient of $\alpha_{T}$ = 0.80 $\pm$ 0.11. This result is consistent with a model of meson production in the atmosphere. We also searched for a diurnal modulation in the underground muon rate by comparing one-hour intervals. No significant diurnal modulation of the muon rate was observed., Comment: 12 pages, 9 figures

Published
2020
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47. Development of ultra-pure NaI(Tl) detectors for the COSINE-200 experiment

Author

Park, B. J., Choe, J. J., Choi, J. S., Gileva, O., Ha, C., Iltis, A., Jeon, E. J., Kim, D. Y., Kim, K. W., Kim, S. K., Kim, Y. D., Ko, Y. J., Lee, C. H., Lee, H. S., Lee, I. S., Lee, M. H., Lee, S. H., Ra, S. J., Son, J. K., and Shin, K. A.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Nuclear Experiment
Abstract

The annual modulation signal observed by the DAMA experiment is a long-standing question in the community of dark matter direct detection. This necessitates an independent verification of its existence using the same detection technique. The COSINE-100 experiment has been operating with 106~kg of low-background NaI(Tl) detectors providing interesting checks on the DAMA signal. However, due to higher backgrounds in the NaI(Tl) crystals used in COSINE-100 relative to those used for DAMA, it was difficult to reach final conclusions. Since the start of COSINE-100 data taking in 2016, we also have initiated a program to develop ultra-pure NaI(Tl) crystals for COSINE-200, the next phase of the experiment. The program includes efforts of raw powder purification, ultra-pure NaI(Tl) crystal growth, and detector assembly techniques. After extensive research and development of NaI(Tl) crystal growth, we have successfully grown a few small-size (0.61$-$0.78 kg) thallium-doped crystals with high radio-purity. A high light yield has been achieved by improvements of our detector assembly technique. Here we report the ultra-pure NaI(Tl) detector developments at the Institute for Basic Science, Korea. The technique developed here will be applied to the production of NaI(Tl) detectors for the COSINE-200 experiment., Comment: 12 pages, 12 figures

Published
2020
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48. The COSINE-100 Liquid Scintillator Veto System

Author

Adhikari, G., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., Franca, L. E., Ha, C., Hahn, I. S., Jeon, E. J., Jo, J. H., Kang, W. G., Kauer, M., Kim, H., Kim, H. J., Kim, K. W., Kim, S. K., Kim, Y. D., Kim, Y. H., Ko, Y. J., Lee, E. K., Lee, H. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Leonard, D. S., Manzato, B. B., Maruyama, R. H., Neal, R. J., Olsen, S. L., Park, B. J., Park, H. K., Park, H. S., Park, K. S., Pitta, R. L. C., Prihtiadi, H., Ra, S. J., Rott, C., Shin, K. A., Scarff, A., Spooner, N. J. C., Thompson, W. G., Yang, L., and Yu, G. H.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract

This paper describes the liquid scintillator veto system for the COSINE-100 dark matter experiment and its performance. The COSINE-100 detector consists of eight NaI(Tl) crystals immersed in 2200~L of linear alkylbenzene-based liquid scintillator. The liquid scintillator tags between 65 and 75\% of the internal $^{40}$K background in the 2--6 keV energy region. We also describe the background model for the liquid scintillator, which is primarily used to assess its energy calibration and threshold.

Published
2020
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49. Depth profile study of $^{210}$Pb in the surface of an NaI(Tl) crystal

Author

Yu, G. H., Ha, C., Jeon, E. J., Kim, K. W., Kim, N. Y., Kim, Y. D., Lee, H. S., Park, H. K., and Rott, C.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The surface $^{210}$Pb is one of the main background sources for dark-matter-search experiments using NaI(Tl) crystals, and its spectral features associated with the beta-decay events for energies less than 60 keV depends on the depth distribution of $^{210}$Pb in the surface of an NaI(Tl) crystal. Therefore, we must understand the profile of surface $^{210}$Pb to precisely model the background measurement in the low-energy region for the low-background experiment using NaI(Tl) crystals. We estimate the depth profile of the surface $^{210}$Pb contamination by modeling the measured spectrum of the alpha emission from the decay of $^{210}$Po at the decay sequence of the surface $^{210}$Pb contamination that is obtained using an $^{222}$Rn-contaminated crystal. In order to describe the energy spectra of the surface contamination we perform a log-likelihood fit of the measured data to a sum of Geant4 Mote Carlo simulations, weighted by an exponential curve as a function of the surface depth. The low- and high-energy events from the beta decay of surface $^{210}$Pb are also modeled to improve the depth profile for shallow depths. We simulate the energy spectra from beta decays of $^{210}$Pb that are exponentially distributed in the surface by following two exponential functions where the mean-depth coefficients are free parameters in the data fitting; we observed that the energy spectra are in good agreement with the measured data.

Published
2020
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50. Value-assigned pulse shape discrimination for neutron detectors

Author

Teh, F. C. E., Lee, J. -W., Zhu, K., Brown, K. W., Chajecki, Z., Lynch, W. G., Tsang, M. B., Anthony, A., Barney, J., Dell'Aquila, D., Estee, J., Hong, B., Jhang, G., Khanal, O. B., Kim, Y. J., Lee, H. S., Lee, J. W., Manfredi, J., Nam, S. H., Niu, C. Y., Park, J. H., Sweany, S., Tsang, C. Y., Wang, R., and Wu, H.

Subjects
Physics - Instrumentation and Detectors
Abstract

Using the waveforms from a digital electronic system, an offline analysis technique on pulse shape discrimination (PSD) has been developed to improve the neutron-gamma separation in a bar-shaped NE-213 scintillator that couples to a photomultiplier tube (PMT) at each end. The new improved method, called the ``valued-assigned PSD'' (VPSD), assigns a normalized fitting residual to every waveform as the PSD value. This procedure then facilitates the incorporation of longitudinal position dependence of the scintillator, which further enhances the PSD capability of the detector system. In this paper, we use radiation emitted from an AmBe neutron source to demonstrate that the resulting neutron-gamma identification has been much improved when compared to the traditional technique that uses the geometric mean of light outputs from both PMTs. The new method has also been modified and applied to a recent experiment at the National Superconducting Cyclotron Laboratory (NSCL) that uses an analog electronic system., Comment: 8 pages, 8 figures

Published
2020
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