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4,202 results on '"Kim, S K"'

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., 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., Kuzminov, V. Kornoukhov 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., Rooh, S. S. Ratkevich 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, 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. Operational Space and Plasma Performance with an RMP-ELM Suppressed Edge

Author

Paz-Soldan, C., Gu, S., Leuthold, N., Lunia, P., Xie, P., Kim, M. W., Kim, S. K., Logan, N. C., Park, J. -K., Suttrop, W., Sun, Y., Weisberg, D. B., Willensdorfer, M., ASDEX-Upgrade, the, DIII-D, EAST, and Teams, KSTAR

Subjects
Physics - Plasma Physics
Abstract

The operational space and global performance of plasmas with edge-localized modes (ELMs) suppressed by resonant magnetic perturbations (RMPs) are surveyed by comparing AUG, DIII-D, EAST, and KSTAR stationary operating points. RMP-ELM suppression is achieved over a range of plasma currents, toroidal fields, and RMP toroidal mode numbers. Consistent operational windows in edge safety factor are found across devices, while windows in plasma shaping parameters are distinct. Accessed pedestal parameters reveal a quantitatively similar pedestal-top density limit for RMP-ELM suppression in all devices of just over 3x1019 m-3. This is surprising given the wide variance of many engineering parameters and edge collisionalities, and poses a challenge to extrapolation of the regime. Wide ranges in input power, confinement time, and stored energy are observed, with the achieved triple product found to scale like the product of current, field, and radius. Observed energy confinement scaling with engineering parameters for RMP-ELM suppressed plasmas are presented and compared with expectations from established H and L-mode scalings, including treatment of uncertainty analysis. Different scaling exponents for individual engineering parameters are found as compared to the established scalings. However, extrapolation to next-step tokamaks ITER and SPARC find overall consistency within uncertainties with the established scalings, finding no obvious performance penalty when extrapolating from the assembled multi-device RMP-ELM suppressed database. Overall this work identifies common physics for RMP-ELM suppression and highlights the need to pursue this no-ELM regime at higher magnetic field and different plasma physical size., Comment: 22 pages, 11 figures

Published
2024
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11. 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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12. 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

14. 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

15. 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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16. 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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17. 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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18. 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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20. 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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21. 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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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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23. A lab scale experiment for keV sterile neutrino search

Author

Lee, Y. C., Kim, H. B., Kim, H. L., Kim, S. K., Kim, Y. H., Kwon, D. H., Lim, H. S., Park, H. S., Woo, K. R., and Yoon, Y. S.

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

We developed a simple small-scale experiment to measure the beta decay spectrum of $^{3}$H. The aim of this research is to investigate the presence of sterile neutrinos in the keV region. Tritium nuclei were embedded in a 1$\times$1$\times$1 cm$^3$ LiF crystal from the $^6$Li(n,$\alpha$)$^3$H reaction. The energy of the beta electrons absorbed in the LiF crystal was measured with a magnetic microcalorimeter at 40 mK. We report a new method of sample preparation, experiments, and analysis of $^3$H beta measurements. The spectrum of a 10-hour measurement agrees well with the expected spectrum of $^3$H beta decay. The analysis results indicate that this method can be used to search for keV-scale sterile neutrinos.

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. Positron accumulation in the GBAR experiment

Author

Blumer, P., Charlton, M., Chung, M., Clade, P., Comini, P., Crivelli, P., Dalkarov, O., Debu, P., Dodd, L., Douillet, A., Guellati, S., Hervieux, P. -A, Hilico, L., Indelicato, P., Janka, G., Jonsell, S., Karr, J. -P., Kim, B. H., Kim, E. S., Kim, S. K., Ko, Y., Kosinski, T., Kuroda, N., Latacz, B. M., Lee, B., Lee, H., Lee, J., Leitee, A. M. M., Leveque, K., Lim, E., Liszkay, L., Lotrus, P., Lunney, D., Manfredi, G., Mansoulie, B., Matusiak, M., Mornacchi, G., Nesvizhevsky, V., Nez, F., Niang, S., Nishi, R., Ohayon, B., Park, K., Paul, N., Perez, P., Procureur, S., Radics, B., Regenfus, C., Reymond, J. -M., Reynaud, S., Rousse, J. -Y., Rousselle, O., Rubbia, A., Rzadkiewicl, J., Sacquin, Y., Schmidt-Kaler, F., Staszczak, M., Szymczyk, K., Tanaka, T., Tuchming, B., Vallage, B., Voronin, A., van der Werf, D. P., Wolf, S., Won, D., Wronka, S., Yamazaki, Y., Yoo, K. H., Yzombard, P., and Baker, C. J.

Subjects
Physics - Plasma Physics
Abstract

We present a description of the GBAR positron (e+) trapping apparatus, which consists of a three stage Buffer Gas Trap (BGT) followed by a High Field Penning Trap (HFT), and discuss its performance. The overall goal of the GBAR experiment is to measure the acceleration of the neutral antihydrogen (H) atom in the terrestrial gravitational field by neutralising a positive antihydrogen ion (H+), which has been cooled to a low temperature, and observing the subsequent H annihilation following free fall. To produce one H+ ion, about 10^10 positrons, efficiently converted into positronium (Ps), together with about 10^7 antiprotons (p), are required. The positrons, produced from an electron linac-based system, are accumulated first in the BGT whereafter they are stacked in the ultra-high vacuum HFT, where we have been able to trap 1.4(2) x 10^9 positrons in 1100 seconds.

Published
2022
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27. 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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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. 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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30. Study of $\chi_{bJ}(nP) \rightarrow \omega \Upsilon(1S)$ at Belle

Author

Belle Collaboration, Abdesselam, A., Adachi, I., Adamczyk, K., Ahn, J. K., Aihara, H., Said, S. Al, Arinstein, K., Arita, Y., Asner, D. M., Atmacan, H., Aulchenko, V., Aushev, T., Ayad, R., Aziz, T., Babu, V., Bahinipati, S., Bakich, A. M., Ban, Y., Barberio, E., Barrett, M., Bauer, M., Behera, P., Beleño, C., Belous, K., Bennett, J., Bernlochner, F., Bessner, M., Besson, D., Bhardwaj, V., Bhuyan, B., Bilka, T., Bilokin, S., Biswal, J., Bloomfield, T., Bobrov, A., Bodrov, D., Bondar, A., Bonvicini, G., Bozek, A., Bra\v, M., Branchini, P., Braun, N., Breibeck, F., Browder, T. E., Budano, A., Campajola, M., Cao, L., Caria, G., \v, D., Chang, M. -C., Chang, P., Chao, Y., Chekelian, V., Chen, A., Chen, K. -F., Chen, Y., Chen, Y. -T., Cheon, B. G., Chilikin, K., Cho, H. E., Cho, K., Cho, S. -J., Chobanova, V., Choi, S. -K., Choi, Y., Choudhury, S., Cinabro, D., Crnkovic, J., Cunliffe, S., Czank, T., Das, S., Dash, N., De Nardo, G., De Pietro, G., Dhamija, R., Di Capua, F., Dingfelder, J., Dole\v, Z., Dong, T. V., Dossett, D., Drásal, Z., Dubey, S., Ecker, P., Eidelman, S., Epifanov, D., Feindt, M., Ferber, T., Frey, A., Fulsom, B. G., Garg, R., Gaur, V., Gabyshev, N., Garmash, A., Gelb, M., Gemmler, J., Getzkow, D., Giordano, F., Giri, A., Goldenzweig, P., Golob, B., Gong, G., Graziani, E., Greenwald, D., Perdekamp, M. Grosse, Grygier, J., Gu, T., Guan, Y., Gudkova, K., Guido, E., Guo, H., Haba, J., Hadjivasiliou, C., Halder, S., Hamer, P., Hara, K., Hara, T., Hartbrich, O., Hasenbusch, J., Hayasaka, K., Hayashii, H., Hazra, S., He, X. H., Heck, M., Hedges, M. T., Heffernan, D., Heider, M., Heller, A., Villanueva, M. Hernandez, Higuchi, T., Hirose, S., Hoshina, K., Hou, W. -S., Hsiung, Y. B., Hsu, C. -L., Huang, K., Huschle, M., Igarashi, Y., Iijima, T., Imamura, M., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Iwata, S., Jacobs, W. W., Jaegle, I., Jang, E. -J., Jeon, H. B., Jia, S., Jin, Y., Joffe, D., Joo, C. W., Joo, K. K., Julius, T., Kahn, J., Kakuno, H., Kaliyar, A. B., Kang, J. H., Kang, K. H., Kapusta, P., Karyan, G., Kataoka, S. U., Kato, Y., Kawai, H., Kawasaki, T., Keck, T., Kichimi, H., Kiesling, C., Kim, B. H., Kim, C. H., Kim, D. Y., Kim, H. J., Kim, H. -J., Kim, J. B., Kim, K. -H., Kim, K. T., Kim, S. H., Kim, S. K., Kim, Y. J., Kim, Y. -K., Kimmel, T., Kindo, H., Kinoshita, K., Kleinwort, C., Klucar, J., Kobayashi, N., Kody\v, P., Koga, Y., Komarov, I., Konno, T., Korobov, A., Korpar, S., Kovalenko, E., Kri\v, P., Kroeger, R., Krohn, J. -F., Krokovny, P., Kronenbitter, B., Kuhr, T., Kulasiri, R., Kumar, M., Kumar, R., Kumara, K., Kumita, T., Kurihara, E., Kuroki, Y., Kuzmin, A., Kvasni\v, P., Kwon, Y. -J., Lai, Y. -T., Lalwani, K., Lange, J. S., Laurenza, M., Lee, I. S., Lee, J. K., Lee, J. Y., Lee, S. C., Leitgab, M., Leitner, R., Levit, D., Lewis, P., Li, C. H., Li, H., Li, J., Li, L. K., Li, Y. B., Gioi, L. Li, Libby, J., Lieret, K., Limosani, A., Liptak, Z., Liu, C., Liu, Y., Liventsev, D., Loos, A., Louvot, R., Lubej, M., Luo, T., MacNaughton, J., Masuda, M., Matsuda, T., Matvienko, D., McNeil, J. T., Merola, M., Metzner, F., Miyabayashi, K., Miyachi, Y., Miyake, H., Miyata, H., Miyazaki, Y., Mizuk, R., Mohanty, G. B., Mohanty, S., Moon, H. K., Moon, T. J., Mori, T., Morii, T., Moser, H. -G., Mrvar, M., Müller, T., Muramatsu, N., Mussa, R., Nagasaka, Y., Nakahama, Y., Nakamura, I., Nakamura, K. R., Nakano, E., Nakano, T., Nakao, M., Nakayama, H., Nakazawa, H., Nanut, T., Natkaniec, Z., Natochii, A., Nayak, L., Nayak, M., Ng, C., Niebuhr, C., Niiyama, M., Nisar, N. K., Nishida, S., Nishimura, K., Nitoh, O., Ogawa, A., Ogawa, K., Ogawa, S., Ohshima, T., Okuno, S., Olsen, S. L., Ono, H., Onuki, Y., Oskin, P., Ostrowicz, W., Oswald, C., Ozaki, H., Pakhlov, P., Pakhlova, G., Pal, B., Pang, T., Panzenböck, E., Pardi, S., Park, C. -S., Park, C. W., Park, H., Park, K. S., Park, S. -H., Passeri, A., Patra, S., Paul, S., Pedlar, T. K., Peng, T., Pes\', L., Pestotnik, R., Peters, M., Piilonen, L. E., Podobnik, T., Popov, V., Prasanth, K., Prencipe, E., Prim, M. T., Prothmann, K., Purohit, M. V., Rabusov, A., Rauch, J., Reisert, B., Resmi, P. K., Ribe\v, E., Ritter, M., R\", M., Rostomyan, A., Rout, N., Rozanska, M., Russo, G., Sahoo, D., Sakai, Y., Salehi, M., Sandilya, S., Santel, D., Santelj, L., Sanuki, T., Sasaki, J., Sasao, N., Sato, Y., Savinov, V., Schmolz, P., Schneider, O., Schnell, G., Schram, M., Schueler, J., Schwanda, C., Schwartz, A. J., Schwenker, B., Seidl, R., Seino, Y., Semmler, D., Senyo, K., Seon, O., Seong, I. S., Sevior, M. E., Shang, L., Shapkin, M., Sharma, C., Shebalin, V., Shen, C. P., Shibata, T. -A., Shibuya, H., Shinomiya, S., Shiu, J. -G., Shwartz, B., Sibidanov, A., Simon, F., Singh, J. B., Sinha, R., Smith, K., Sokolov, A., Soloviev, Y., Solovieva, E., Stani\v, S., Stari\v, M., Steder, M., Stottler, Z. S., Strube, J. F., Stypula, J., Sugihara, S., Sugiyama, A., Sumihama, M., Sumisawa, K., Sumiyoshi, T., Sutcliffe, W., Suzuki, K., Suzuki, S., Suzuki, S. Y., Takeichi, H., Takizawa, M., Tamponi, U., Tanaka, M., Tanaka, S., Tanida, K., Taniguchi, N., Tao, Y., Taylor, G. N., Tenchini, F., Teramoto, Y., Thampi, A., Tiwary, R., Trabelsi, K., Tsuboyama, T., Uchida, M., Ueda, I., Uehara, S., Uglov, T., Unno, Y., Uno, K., Uno, S., Urquijo, P., Ushiroda, Y., Usov, Y., Vahsen, S. E., Van Hulse, C., Van Tonder, R., Vanhoefer, P., Varner, G., Varvell, K. E., Vervink, K., Vinokurova, A., Vorobyev, V., Vossen, A., Wagner, M. N., Waheed, E., Wang, B., Wang, C. H., Wang, D., Wang, E., Wang, M. -Z., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Watanuki, S., Wedd, R., Wehle, S., Werbycka, O., Widmann, E., Wiechczynski, J., Won, E., Xu, X., Yabsley, B. D., Yamada, S., Yamamoto, H., Yamashita, Y., Yan, W., Yang, S. B., Yashchenko, S., Ye, H., Yelton, J., Yin, J. H., Yook, Y., Yuan, C. Z., Yusa, Y., Zhang, C. C., Zhang, J., Zhang, L. M., Zhang, Z. P., Zhao, L., Zhilich, V., Zhukova, V., Zhulanov, V., Zivko, T., Zupanc, A., and Zwahlen, N.

Subjects
High Energy Physics - Experiment
Abstract

We report results from a study of hadronic transitions of the $\chi_{bJ}(nP)$ states of bottomonium at Belle. The $P$-wave states are reconstructed in transitions to the $\Upsilon(1S)$ with the emission of an $\omega$ meson. The transitions of the $n=2$ triplet states provide a unique laboratory in which to study nonrelativistic quantum chromodynamics, as the kinematic threshold for production of an $\omega$ and $\Upsilon(1S)$ lies between the $J=0$ and $J=1$ states. A search for the $\chi_{bJ}(3P)$ states is also reported.

Published
2021

31. 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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32. 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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33. 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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34. A Simple Algorithm for the Constrained Sequence Problems

Author

Chin, Francis Yuk Lun, Ho, Ngai Lam, De Santis, Alfredo, and Kim, S. K.

Subjects
Computer Science - Data Structures and Algorithms
Abstract

In this paper we address the constrained longest common subsequence problem. Given two sequences $X$, $Y$ and a constrained sequence $P$, a sequence $Z$ is a constrained longest common subsequence for $X$ and $Y$ with respect to $P$ if $Z$ is the longest subsequence of $X$ and $Y$ such that $P$ is a subsequence of $Z$. Recently, Tsai \cite{Tsai} proposed an $O(n^2 \cdot m^2 \cdot r)$ time algorithm to solve this problem using dynamic programming technique, where $n$, $m$ and $r$ are the lengths of $X$, $Y$ and $P$, respectively. In this paper, we present a simple algorithm to solve the constrained longest common subsequence problem in $O(n \cdot m \cdot r)$ time and show that the constrained longest common subsequence problem is equivalent to a special case of the constrained multiple sequence alignment problem which can also be solved., Comment: https://doi.org/10.1016/j.ipl.2004.02.008

Published
2021
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35. 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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36. 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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37. Search for the Decay $B_s^0 \rightarrow \eta^\prime \eta$

Author

Belle Collaboration, Abdesselam, A., Adachi, I., Adamczyk, K., Ahn, J. K., Aihara, H., Said, S. Al, Arinstein, K., Arita, Y., Asner, D. M., Atmacan, H., Aulchenko, V., Aushev, T., Ayad, R., Aziz, T., Babu, V., Bahinipati, S., Bakich, A. M., Ban, Y., Barberio, E., Barrett, M., Bauer, M., Behera, P., Beleño, C., Belous, K., Bennett, J., Berger, M., Bernlochner, F., Bessner, M., Besson, D., Bhardwaj, V., Bhuyan, B., Bilka, T., Biswal, J., Bloomfield, T., Bobrov, A., Bondar, A., Bonvicini, G., Bozek, A., Bračko, M., Braun, N., Breibeck, F., Browder, T. E., Campajola, M., Cao, L., Caria, G., Červenkov, D., Chang, M. -C., Chang, P., Chao, Y., Chekelian, V., Chen, A., Chen, K. -F., Chen, Y., Chen, Y. -T., Cheon, B. G., Chilikin, K., Cho, H. E., Cho, K., Cho, S. -J., Chobanova, V., Choi, S. -K., Choi, Y., Choudhury, S., Cinabro, D., Crnkovic, J., Cunliffe, S., Czank, T., Das, S., Dash, N., De Nardo, G., Dhamija, R., Di Capua, F., Dingfelder, J., Doležal, Z., Dong, T. V., Dossett, D., Drásal, Z., Dubey, S., Eidelman, S., Epifanov, D., Feindt, M., Ferber, T., Frey, A., Frost, O., Fulsom, B. G., Garg, R., Gaur, V., Gabyshev, N., Garmash, A., Gelb, M., Gemmler, J., Getzkow, D., Giordano, F., Giri, A., Goldenzweig, P., Golob, B., Greenwald, D., Perdekamp, M. Grosse, Grygier, J., Grzymkowska, O., Guan, Y., Guido, E., Guo, H., Haba, J., Hadjivasiliou, C., Hamer, P., Hara, K., Hara, T., Hartbrich, O., Hasenbusch, J., Hayasaka, K., Hayashii, H., He, X. H., Heck, M., Hedges, M. T., Heffernan, D., Heider, M., Heller, A., Villanueva, M. Hernandez, Higuchi, T., Hirose, S., Hoshina, K., Hou, W. -S., Hsiung, Y. B., Hsu, C. -L., Huang, K., Huschle, M., Igarashi, Y., Iijima, T., Imamura, M., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Iwata, S., Jacobs, W. W., Jaegle, I., Jang, E. -J., Jeon, H. B., Jia, S., Jin, Y., Joffe, D., Jones, M., Joo, C. W., Joo, K. K., Julius, T., Kahn, J., Kakuno, H., Kaliyar, A. B., Kang, J. H., Kang, K. H., Kapusta, P., Karyan, G., Kataoka, S. U., Kato, Y., Kawai, H., Kawasaki, T., Keck, T., Kichimi, H., Kiesling, C., Kim, B. H., Kim, C. H., Kim, D. Y., Kim, H. J., Kim, H. -J., Kim, J. B., Kim, K. -H., Kim, K. T., Kim, S. H., Kim, S. K., Kim, Y. J., Kim, Y. -K., Kimmel, T., Kindo, H., Kinoshita, K., Kleinwort, C., Klucar, J., Kobayashi, N., Kodyš, P., Koga, Y., Komarov, I., Konno, T., Korpar, S., Kotchetkov, D., Križan, P., Kroeger, R., Krohn, J. -F., Krokovny, P., Kronenbitter, B., Kuhr, T., Kulasiri, R., Kumar, M., Kumar, R., Kumara, K., Kumita, T., Kurihara, E., Kuroki, Y., Kuzmin, A., Kvasnička, P., Kwon, Y. -J., Lai, Y. -T., Lalwani, K., Lange, J. S., Lee, I. S., Lee, J. K., Lee, J. Y., Lee, S. C., Leitgab, M., Leitner, R., Levit, D., Lewis, P., Li, C. H., Li, H., Li, J., Li, L. K., Li, Y., Li, Y. B., Gioi, L. Li, Libby, J., Lieret, K., Limosani, A., Liptak, Z., Liu, C., Liu, Y., Liventsev, D., Loos, A., Louvot, R., Lubej, M., Luo, T., MacNaughton, J., Masuda, M., Matsuda, T., Matvienko, D., McNeil, J. T., Merola, M., Metzner, F., Miyabayashi, K., Miyachi, Y., Miyake, H., Miyata, H., Miyazaki, Y., Mizuk, R., Mohanty, G. B., Mohanty, S., Moon, H. K., Moon, T. J., Mori, T., Morii, T., Moser, H. -G., Mrvar, M., Müller, T., Muramatsu, N., Mussa, R., Nagasaka, Y., Nakahama, Y., Nakamura, I., Nakamura, K. R., Nakano, E., Nakano, T., Nakao, M., Nakayama, H., Nakazawa, H., Nanut, T., Nath, K. J., Natkaniec, Z., Natochii, A., Nayak, L., Nayak, M., Ng, C., Niebuhr, C., Niiyama, M., Nisar, N. K., Nishida, S., Nishimura, K., Nitoh, O., Ogawa, A., Ogawa, K., Ogawa, S., Ohshima, T., Okuno, S., Olsen, S. L., Ono, H., Onuki, Y., Oskin, P., Ostrowicz, W., Oswald, C., Ozaki, H., Pakhlov, P., Pakhlova, G., Pal, B., Pang, T., Panzenböck, E., Pardi, S., Park, C. -S., Park, C. W., Park, H., Park, K. S., Park, S. -H., Patra, S., Paul, S., Pedlar, T. K., Peng, T., Pesántez, L., Pestotnik, R., Peters, M., Piilonen, L. E., Podobnik, T., Popov, V., Prasanth, K., Prencipe, E., Prim, M. T., Prothmann, K., Purohit, M. V., Rabusov, A., Rauch, J., Reisert, B., Resmi, P. K., Ribežl, E., Ritter, M., Röhrken, M., Rorie, J., Rostomyan, A., Rout, N., Rozanska, M., Russo, G., Sahoo, D., Sakai, Y., Salehi, M., Sandilya, S., Santel, D., Santelj, L., Sanuki, T., Sasaki, J., Sasao, N., Sato, Y., Savinov, V., Schlüter, T., Schneider, O., Schnell, G., Schram, M., Schueler, J., Schwanda, C., Schwartz, A. J., Schwenker, B., Seidl, R., Seino, Y., Semmler, D., Senyo, K., Seon, O., Seong, I. S., Sevior, M. E., Shang, L., Shapkin, M., Sharma, C., Shebalin, V., Shen, C. P., Shibata, T. -A., Shibuya, H., Shinomiya, S., Shiu, J. -G., Shwartz, B., Sibidanov, A., Simon, F., Singh, J. B., Sinha, R., Smith, K., Sokolov, A., Soloviev, Y., Solovieva, E., Stanič, S., Starič, M., Steder, M., Stottler, Z., Strube, J. F., Stypula, J., Sugihara, S., Sugiyama, A., Sumihama, M., Sumisawa, K., Sumiyoshi, T., Sutcliffe, W., Suzuki, K., Suzuki, S., Suzuki, S. Y., Takeichi, H., Takizawa, M., Tamponi, U., Tanaka, M., Tanaka, S., Tanida, K., Taniguchi, N., Tao, Y., Taylor, G. N., Tenchini, F., Teramoto, Y., Thampi, A., Trabelsi, K., Tsuboyama, T., Uchida, M., Ueda, I., Uehara, S., Uglov, T., Unno, Y., Uno, S., Urquijo, P., Ushiroda, Y., Usov, Y., Vahsen, S. E., Van Hulse, C., Van Tonder, R., Vanhoefer, P., Varner, G., Varvell, K. E., Vervink, K., Vinokurova, A., Vorobyev, V., Vossen, A., Wagner, M. N., Waheed, E., Wang, B., Wang, C. H., Wang, E., Wang, M. -Z., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Watanuki, S., Wedd, R., Wehle, S., Widmann, E., Wiechczynski, J., Williams, K. M., Won, E., Xu, X., Yabsley, B. D., Yamada, S., Yamamoto, H., Yamashita, Y., Yan, W., Yang, S. B., Yashchenko, S., Ye, H., Yelton, J., Yin, J. H., Yook, Y., Yuan, C. Z., Yusa, Y., Zhang, C. C., Zhang, J., Zhang, L. M., Zhang, Z. P., Zhao, L., Zhilich, V., Zhukova, V., Zhulanov, V., Zivko, T., Zupanc, A., and Zwahlen, N.

Subjects
High Energy Physics - Experiment
Abstract

In the Standard Model (SM) charmless hadronic decays $B_s^0 \rightarrow \eta^\prime \eta$ proceed via tree-level $b\to u$ and penguin $b\to s$ transitions. Penguin transitions are sensitive to Beyond-the-Standard-Model (BSM) physics scenarios and could affect the branching fractions and {\it CP} asymmetries in such decays. Once branching fractions for two-body decays $B_s \to \eta\eta, \eta\eta^{\prime}, \eta^{\prime}\eta^{\prime} $ are measured, and the theoretical uncertainties are reduced, it would be possible to extract {\it CP} violating parameters from the data using the formalism based on SU(3)/U(3) symmetry. To achieve this goal, at least four of these six branching fractions need to be measured. Only the branching fraction for $B_s^0 \to \eta^{\prime}\eta^{\prime}$ has been measured so far.

Published
2020

38. Measurement of Branching Fractions of $\Lambda_{c}^{+} \rightarrow \eta\Lambda\pi^{+}$, $\eta \Sigma^{0} \pi^{+}$, $\Lambda(1670) \pi^{+}$, and $\eta \Sigma(1385)^{+}$

Author

Lee, J. Y., Tanida, K., Kato, Y., Kim, S. K., Yang, S. B., Adachi, I., Ahn, J. K., Aihara, H., Said, S. Al, Asner, D. M., Aushev, T., Ayad, R., Babu, V., Bahinipati, S., Behera, P., Beleño, C., Bennett, J., Bessner, M., Bhuyan, B., Bilka, T., Biswal, J., Bonvicini, G., Bozek, A., Bračko, M., Browder, T. E., Campajola, M., Cao, L., Cervenkov, D., Chang, M. -C., Chang, P., Chekelian, V., Chen, A., Cheon, B. G., Chilikin, K., Cho, K., Choi, S. -K., Choi, Y., Choudhury, S., Cinabro, D., Cunliffe, S., De Nardo, G., Di Capua, F., Doležal, Z., Dong, T. V., Eidelman, S., Epifanov, D., Ferber, T., Fulsom, B. G., Garg, R., Gaur, V., Garmash, A., Giri, A., Goldenzweig, P., Golob, B., Hadjivasiliou, C., Hartbrich, O., Hayasaka, K., Hayashii, H., Hedges, M. T., Villanueva, M. Hernandez, Hsu, C. -L., Inami, K., Ishikawa, A., Itoh, R., Iwasaki, M., Jacobs, W. W., Jang, E. -J., Jia, S., Jin, Y., Joo, C. W., Joo, K. K., Kang, K. H., Karyan, G., Kichimi, H., Kiesling, C., Kim, B. H., Kim, D. Y., Kim, K. -H., Kim, K. T., Kim, S. H., Kim, Y. J., Kim, Y. -K., Kinoshita, K., Kodyš, P., Korpar, S., Kotchetkov, D., Križan, P., Kroeger, R., Krokovny, P., Kuhr, T., Kulasiri, R., Kumara, K., Kuzmin, A., Kwon, Y. -J., Lee, S. C., Li, C. H., Li, L. K., Li, Y. B., Gioi, L. Li, Libby, J., Lieret, K., Liptak, Z., Liventsev, D., Luo, T., MacQueen, C., Masuda, M., Matsuda, T., Matvienko, D., Merola, M., Miyabayashi, K., Mizuk, R., Mohanty, G. B., Moon, T. J., Mori, T., Mussa, R., Nakano, T., Nakao, M., Natochii, A., Nayak, M., Niiyama, M., Nisar, N. K., Nishida, S., Ogawa, K., Ogawa, S., Olsen, S. L., Ono, H., Onuki, Y., Oskin, P., Pakhlov, P., Pakhlova, G., Pardi, S., Park, S. -H., Patra, S., Paul, S., Pedlar, T. K., Pestotnik, R., Piilonen, L. E., Podobnik, T., Popov, V., Prencipe, E., Prim, M. T., Rostomyan, A., Rout, N., Russo, G., Sahoo, D., Sakai, Y., Sandilya, S., Sangal, A., Santelj, L., Savinov, V., Schnell, G., Schueler, J., Schwanda, C., Schwartz, A. J., Seidl, R., Seino, Y., Senyo, K., Sevior, M. E., Shapkin, M., Shebalin, V., Shiu, J. -G., Shwartz, B., Sokolov, A., Solovieva, E., Stanič, S., Starič, M., Stottler, Z. S., Sumihama, M., Sumiyoshi, T., Sutcliffe, W., Takizawa, M., Tamponi, U., Tenchini, F., Uchida, M., Uglov, T., Uno, S., Usov, Y., Vahsen, S. E., Van Tonder, R., Varner, G., Vinokurova, A., Vorobyev, V., Vossen, A., Wang, C. H., Wang, E., Wang, M. -Z., Wang, P., Watanabe, M., Watanuki, S., Wehle, S., Wiechczynski, J., Xu, X., Yabsley, B. D., Yan, W., Ye, H., Yelton, J., Yin, J. H., Yuan, C. Z., Yusa, Y., Zhang, Z. P., Zhilich, V., Zhukova, V., and Zhulanov., V.

Subjects
High Energy Physics - Experiment
Abstract

We report branching fraction measurements of four decay modes of the $\Lambda_{c}^{+}$ baryon, each of which includes an $\eta$ meson and a $\Lambda$ baryon in the final state, and all of which are measured relative to the $\Lambda_{c}^{+} \rightarrow p K^{-} pi^{+}$ decay mode. The results are based on a $980~\mathrm{fb^{-1}}$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. Two decays, $\eta \Sigma^{0} \pi^{+}$ and $\Lambda(1670) \pi^{+}$, are observed for the first time, while the measurements of the other decay modes, $\Lambda_{c}^{+} \rightarrow \eta\Lambda\pi^{+}$ and $\eta\Sigma(1385)^{+}$, are more precise than those made previously. We obtain $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \eta \Lambda \pi^{+})/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $0.293 \pm 0.003 \pm 0.014$, $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \eta \Sigma^{0} \pi^{+})/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $0.120 \pm 0.006 \pm 0.006$, $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \Lambda(1670) \pi^{+}) \times \mathcal{B}(\Lambda(1670) \rightarrow \eta \Lambda)/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $(5.54 \pm 0.29 \pm 0.73 ) \times 10^{-2}$, and $\mathcal{B}(\Lambda_{c}^{+} \rightarrow \eta \Sigma(1385)^{+})/\mathcal{B}(\Lambda_{c}^{+} \rightarrow p K^{-} \pi^{+})$ = $0.192 \pm 0.006 \pm 0.016$. The mass and width of the $\Lambda(1670)$ are also precisely determined to be $1674.3 \pm 0.8 \pm 4.9~{\rm MeV}/c^{2}$ and $36.1 \pm 2.4 \pm 4.8~{\rm MeV}$, respectively, where the uncertainties are statistical and systematic, respectively., Comment: To be submitted to Physical Review D

Published
2020
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39. Measurement of two-particle correlations in hadronic $e^{+}e^{-}$ collisions at Belle

Author

Belle Collaboration, Abdesselam, A., Adachi, I., Adamczyk, K., Ahn, J. K., Aihara, H., Said, S. Al, Arinstein, K., Arita, Y., Asner, D. M., Atmacan, H., Aulchenko, V., Aushev, T., Ayad, R., Aziz, T., Babu, V., Bahinipati, S., Bakich, A. M., Ban, Y., Barberio, E., Barrett, M., Bauer, M., Behera, P., Beleño, C., Belous, K., Bennett, J., Berger, M., Bernlochner, F., Bessner, M., Besson, D., Bhardwaj, V., Bhuyan, B., Bilka, T., Biswal, J., Bloomfield, T., Bobrov, A., Bondar, A., Bonvicini, G., Bozek, A., Bračko, M., Braun, N., Breibeck, F., Browder, T. E., Campajola, M., Cao, L., Caria, G., Červenkov, D., Chang, M. -C., Chang, P., Chao, Y., Chekelian, V., Chen, A., Chen, K. -F., Chen, Y., Chen, Y. -C., Chen, Y. -T., Cheon, B. G., Chilikin, K., Cho, H. E., Cho, K., Cho, S. -J., Chobanova, V., Choi, S. -K., Choi, Y., Choudhury, S., Cinabro, D., Crnkovic, J., Cunliffe, S., Czank, T., Dash, N., De Nardo, G., Dhamija, R., Di Capua, F., Dingfelder, J., Doležal, Z., Dong, T. V., Dossett, D., Drásal, Z., Dubey, S., Eidelman, S., Epifanov, D., Feindt, M., Ferber, T., Frey, A., Frost, O., Fulsom, B. G., Garg, R., Gaur, V., Gabyshev, N., Garmash, A., Gelb, M., Gemmler, J., Getzkow, D., Giordano, F., Giri, A., Goldenzweig, P., Golob, B., Greenwald, D., Perdekamp, M. Grosse, Grygier, J., Grzymkowska, O., Guan, Y., Guido, E., Guo, H., Haba, J., Hadjivasiliou, C., Hamer, P., Hara, K., Hara, T., Hartbrich, O., Hasenbusch, J., Hayasaka, K., Hayashii, H., He, X. H., Heck, M., Hedges, M. T., Heffernan, D., Heider, M., Heller, A., Villanueva, M. Hernandez, Higuchi, T., Hirose, S., Hoshina, K., Hou, W. -S., Hsiung, Y. B., Hsu, C. -L., Huang, K., Huschle, M., Igarashi, Y., Iijima, T., Imamura, M., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Iwata, S., Jacobs, W. W., Jaegle, I., Jang, E. -J., Jeon, H. B., Jia, S., Jin, Y., Joffe, D., Jones, M., Joo, C. W., Joo, K. K., Julius, T., Kahn, J., Kakuno, H., Kaliyar, A. B., Kang, J. H., Kang, K. H., Kapusta, P., Karyan, G., Kataoka, S. U., Kato, Y., Kawai, H., Kawasaki, T., Keck, T., Kichimi, H., Kiesling, C., Kim, B. H., Kim, C. H., Kim, D. Y., Kim, H. J., Kim, H. -J., Kim, J. B., Kim, K. -H., Kim, K. T., Kim, S. H., Kim, S. K., Kim, Y. J., Kim, Y. -K., Kimmel, T., Kindo, H., Kinoshita, K., Kleinwort, C., Klucar, J., Kobayashi, N., Kodyš, P., Koga, Y., Komarov, I., Konno, T., Korpar, S., Kotchetkov, D., Križan, P., Kroeger, R., Krohn, J. -F., Krokovny, P., Kronenbitter, B., Kuhr, T., Kulasiri, R., Kumar, R., Kumara, K., Kumita, T., Kurihara, E., Kuroki, Y., Kuzmin, A., Kvasnička, P., Kwon, Y. -J., Lai, Y. -T., Lalwani, K., Lange, J. S., Lee, I. S., Lee, J. K., Lee, J. Y., Lee, S. C., Lee, Y. -J., Leitgab, M., Leitner, R., Levit, D., Lewis, P., Li, C. H., Li, H., Li, J., Li, L. K., Li, Y., Li, Y. B., Gioi, L. Li, Libby, J., Lieret, K., Limosani, A., Lin, C. -W., Liptak, Z., Liu, C., Liu, Y., Liventsev, D., Loos, A., Louvot, R., Lubej, M., Luo, T., MacNaughton, J., Masuda, M., Matsuda, T., Matvienko, D., McNeil, J. T., Merola, M., Metzner, F., Miyabayashi, K., Miyachi, Y., Miyake, H., Miyata, H., Miyazaki, Y., Mizuk, R., Mohanty, G. B., Mohanty, S., Moon, H. K., Moon, T. J., Mori, T., Morii, T., Moser, H. -G., Mrvar, M., Müller, T., Muramatsu, N., Mussa, R., Nagasaka, Y., Nakahama, Y., Nakamura, I., Nakamura, K. R., Nakano, E., Nakano, T., Nakao, M., Nakayama, H., Nakazawa, H., Nanut, T., Nath, K. J., Natkaniec, Z., Natochii, A., Nayak, L., Nayak, M., Ng, C., Niebuhr, C., Niiyama, M., Nisar, N. K., Nishida, S., Nishimura, K., Nitoh, O., Ogawa, A., Ogawa, K., Ogawa, S., Ohshima, T., Okuno, S., Olsen, S. L., Ono, H., Onuki, Y., Oskin, P., Ostrowicz, W., Oswald, C., Ozaki, H., Pakhlov, P., Pakhlova, G., Pal, B., Pang, T., Panzenböck, E., Pardi, S., Park, C. -S., Park, C. W., Park, H., Park, K. S., Park, S. -H., Patra, S., Paul, S., Pedlar, T. K., Peng, T., Pesántez, L., Pestotnik, R., Peters, M., Piilonen, L. E., Podobnik, T., Popov, V., Prasanth, K., Prencipe, E., Prim, M. T., Prothmann, K., Purohit, M. V., Rabusov, A., Rauch, J., Reisert, B., Resmi, P. K., Ribežl, E., Ritter, M., Röhrken, M., Rorie, J., Rostomyan, A., Rout, N., Rozanska, M., Russo, G., Sahoo, D., Sakai, Y., Salehi, M., Sandilya, S., Santel, D., Santelj, L., Sanuki, T., Sasaki, J., Sasao, N., Sato, Y., Savinov, V., Schlüter, T., Schneider, O., Schnell, G., Schram, M., Schueler, J., Schwanda, C., Schwartz, A. J., Schwenker, B., Seidl, R., Seino, Y., Semmler, D., Senyo, K., Seon, O., Seong, I. S., Sevior, M. E., Shang, L., Shapkin, M., Shebalin, V., Shen, C. P., Shibata, T. -A., Shibuya, H., Shinomiya, S., Shiu, J. -G., Shwartz, B., Sibidanov, A., Simon, F., Singh, J. B., Sinha, R., Smith, K., Sokolov, A., Soloviev, Y., Solovieva, E., Stanič, S., Starič, M., Steder, M., Stottler, Z., Strube, J. F., Stypula, J., Sugihara, S., Sugiyama, A., Sumihama, M., Sumisawa, K., Sumiyoshi, T., Sutcliffe, W., Suzuki, K., Suzuki, S., Suzuki, S. Y., Takeichi, H., Takizawa, M., Tamponi, U., Tanaka, M., Tanaka, S., Tanida, K., Taniguchi, N., Tao, Y., Taylor, G. N., Tenchini, F., Teramoto, Y., Thampi, A., Trabelsi, K., Tsuboyama, T., Uchida, M., Ueda, I., Uehara, S., Uglov, T., Unno, Y., Uno, S., Urquijo, P., Ushiroda, Y., Usov, Y., Vahsen, S. E., Van Hulse, C., Van Tonder, R., Vanhoefer, P., Varner, G., Varvell, K. E., Vervink, K., Vinokurova, A., Vorobyev, V., Vossen, A., Wagner, M. N., Waheed, E., Wang, B., Wang, C. H., Wang, E., Wang, M. -Z., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Watanuki, S., Wedd, R., Wehle, S., Widmann, E., Wiechczynski, J., Williams, K. M., Won, E., Xu, X., Yabsley, B. D., Yamada, S., Yamamoto, H., Yamashita, Y., Yan, W., Yang, S. B., Yashchenko, S., Ye, H., Yelton, J., Yin, J. H., Yook, Y., Yuan, C. Z., Yusa, Y., Zhang, C. C., Zhang, J., Zhang, L. M., Zhang, Z. P., Zhao, L., Zhilich, V., Zhukova, V., Zhulanov, V., Zivko, T., Zupanc, A., and Zwahlen, N.

Subjects
High Energy Physics - Experiment
Abstract

The enhancement of charged-particle pairs with large pseudorapidity difference and small azimuthal angle difference, often referred to as the ``ridge signal'', is a phenomenon widely observed in high multiplicity proton-proton, proton-ion and deutron-ion collisions, which is not yet fully understood. In heavy-ion collisions, the hydrodynamic expansion of the Quark-Gluon Plasma is one of the possible explanations of the origin of the ridge signal. Measurements in the $e^+e^-$ collision system, without the complexities introduced by hadron structure in the initial state, can serve as a complementary probe to examine the formation of a ridge signal. The first measurement of two-particle angular correlation functions in high multiplicity $e^+e^-$ collisions at $\sqrt{s}=10.52$ GeV is reported. The hadronic $e^+e^-$ annihilation data collected by the Belle detector at KEKB are used in this study. Two-particle angular correlation functions are measured over the full azimuth and large pseudorapidity intervals which are defined by either the electron beam axis or the event thrust as a function of charged particle multiplicity. The measurement in the event thrust analysis, with mostly outgoing quark pairs determining the reference axis, is sensitive to the region of additional soft gluon emissions. No significant ridge signal is observed with either coordinates analyses. Near side jet correlations appear to be absent in the thrust axis analysis. The measurements are compared to predictions from various event generators and expected to provide new constraints to the phenomenological models in the low energy regime., Comment: 13 pages, 5 figures. Conference paper for ICHEP 2020

Published
2020

40. First Determination of the Spin and Parity of a Charmed-Strange Baryon, $\Xi_{c}(2970)^+$

Author

Belle Collaboration, Moon, T. J., Tanida, K., Kato, Y., Kim, S. K., Adachi, I., Ahn, J. K., Aihara, H., Said, S. Al, Asner, D. M., Aulchenko, V., Aushev, T., Ayad, R., Babu, V., Bahinipati, S., Behera, P., Beleño, C., Bennett, J., Bessner, M., Bhuyan, B., Bilka, T., Biswal, J., Bonvicini, G., Bozek, A., Bračko, M., Browder, T. E., Campajola, M., Cao, L., Červenkov, D., Chang, M. -C., Chang, P., Chen, A., Cheon, B. G., Chilikin, K., Cho, K., Choi, S. -K., Choi, Y., Choudhury, S., Cinabro, D., Cunliffe, S., Dash, N., De Nardo, G., Di Capua, F., Doležal, Z., Dong, T. V., Dossett, D., Dubey, S., Eidelman, S., Epifanov, D., Ferber, T., Fulsom, B. G., Garg, R., Gaur, V., Gabyshev, N., Garmash, A., Giri, A., Goldenzweig, P., Golob, B., Hadjivasiliou, C., Hartbrich, O., Hayasaka, K., Hayashii, H., Hedges, M. T., Hou, W. -S., Hsu, C. -L., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Jacobs, W. W., Jia, S., Jin, Y., Joo, K. K., Kang, K. H., Karyan, G., Kawasaki, T., Kichimi, H., Kiesling, C., Kim, B. H., Kim, D. Y., Kim, K. T., Kim, S. H., Kim, Y. J., Kim, Y. -K., Kimmel, T. D., Kinoshita, K., Kodyš, P., Korpar, S., Kotchetkov, D., Križan, P., Kroeger, R., Krokovny, P., Kuhr, T., Kumar, R., Kumara, K., Kuzmin, A., Lee, I. S., Lee, J. Y., Lee, S. C., Li, L. K., Li, Y. B., Gioi, L. Li, Libby, J., Liptak, Z., Liventsev, D., Luo, T., MacQueen, C., Masuda, M., Matsuda, T., Matvienko, D., Merola, M., Miyabayashi, K., Miyata, H., Mizuk, R., Mohanty, G. B., Mohanty, S., Mori, T., Mussa, R., Nakano, T., Nakao, M., Natkaniec, Z., Natochii, A., Nayak, M., Niiyama, M., Nisar, N. K., Nishida, S., Ogawa, K., Ogawa, S., Ono, H., Pakhlov, P., Pakhlova, G., Pardi, S., Park, H., Park, S. -H., Patra, S., Paul, S., Pedlar, T. K., Pestotnik, R., Piilonen, L. E., Podobnik, T., Popov, V., Prencipe, E., Prim, M. T., Ritter, M., Rout, N., Russo, G., Sahoo, D., Sakai, Y., Sandilya, S., Sangal, A., Santelj, L., Savinov, V., Schnell, G., Schueler, J., Schwanda, C., Seidl, R., Seino, Y., Senyo, K., Sevior, M. E., Shapkin, M., Shen, C. P., Shiu, J. -G., Shwartz, B., Solovieva, E., Starič, M., Stottler, Z. S., Sumihama, M., Sumisawa, K., Sumiyoshi, T., Sutcliffe, W., Takizawa, M., Tamponi, U., Tenchini, F., Trabelsi, K., Uchida, M., Uehara, S., Uglov, T., Unno, Y., Uno, S., Urquijo, P., Vahsen, S. E., Van Tonder, R., Varner, G., Vinokurova, A., Vorobyev, V., Vossen, A., Wang, C. H., Wang, E., Wang, M. -Z., Wang, P., Wehle, S., Wiechczynski, J., Xu, X., Yabsley, B. D., Yang, S. B., Ye, H., Yelton, J., Yin, J. H., Yuan, C. Z., Zhang, Z. P., Zhilich, V., Zhukova, V., and Zhulanov, V.

Subjects
High Energy Physics - Experiment
Abstract

We report results from a study of the spin and parity of $\Xi_{c}(2970)^+$ using a $980~\mathrm{fb^{-1}}$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The decay angle distributions in the chain $\Xi_{c}(2970)^+ \to \Xi_c(2645)^{0}\pi^{+} \to \Xi_c^{+}\pi^{-}\pi^{+}$ are analyzed to determine the spin of this charmed-strange baryon. The angular distributions strongly favor the $\Xi_{c}(2970)^+$ spin $J =1/2$ over $3/2$ or $5/2$, under an assumption that the lowest partial wave dominates in the decay. We also measure the ratio of $\Xi_{c}(2970)^+$ decay branching fractions $R={\mathcal{B}[ \Xi_{c}(2970)^+ \to \Xi_c(2645)^{0}\pi^{+} ]} / { \mathcal{B}[ \Xi_{c}(2970)^+ \to \Xi_c^{\prime0}\pi^{+} ]} =1.67 \pm 0.29\mathrm{(stat.)}^{ +0.15}_{ -0.09}\mathrm{(syst.)} \pm 0.25\mathrm{(IS)}$, where the last uncertainty is due to possible isospin-symmetry-breaking effects. This $R$ value favors the spin-parity $J^P=1/2^+$ with the spin of the light-quark degrees of freedom $s_{l}=0$. This is the first determination of the spin and parity of a charmed-strange baryon., Comment: To be submitted to Physical Review Letters

Published
2020
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41. Positron production using a 9 MeV electron linac for the GBAR experiment

Author

Charlton, M., Choi, J. J., Chung, M., Clade, P., Comini, P., Crepin, P-P., Crivelli, P., Dalkarov, O., Debu, P., Dodd, L., Douillet, A., Guellati-Khelifa, S., Hervieux, P-A., Hilico, L., Husson, A., Indelicato, P., Janka, G., Jonsell, S., Karr, J-P., Kim, B. H., Kim, E-S., Kim, S. K., Ko, Y., Kosinski, T., Kuroda, N., Latacz, B., Lee, H., Lee, J., Leite, A. M. M., Leveque, K., Lim, E., Liszkay, L., Lotrus, P., Louvradoux, T., Lunney, D., Manfredi, G., Mansoulie, B., Matusiak, M., Mornacchi, G., Nesvizhevsky, V. V., Nez, F., Niang, S., Nishi, R., Nourbaksh, S., Park, K. H., Paul, N., Perez, P., Procureur, S., Radics, B., Regenfus, C., Rey, J-M., Reymond, J-M., Reynaud, S., Rousse, J-Y., Rousselle, O., Rubbia, A., Rzadkiewicz, J., Sacquin, Y., Schmidt-Kaler, F., Staszczak, M., Tuchming, B., Vallage, B., Voronin, A., Welker, A., van der Werf, D. P., Wolf, S., Won, D., Wronka, S., Yamazaki, Y., and Yoo, K-H.

Subjects
Physics - Instrumentation and Detectors
Abstract

For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN's Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. Staying below 10 MeV ensures no persistent radioactive activation in the target zone and that the radiation level outside the biological shield is safe for public access. An annealed tungsten-mesh assembly placed directly behind the target acts as a positron moderator. The system produces $5\times10^7$ slow positrons per second, a performance demonstrating that a low-energy electron linac is a superior choice over positron-emitting radioactive sources for high positron flux., Comment: published in NIM A. 33 pages 9 figures

Published
2020
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42. 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

43. 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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44. 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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45. 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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46. 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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47. s-Step Orthomin and GMRES implemented on parallel computers

Author

Chronopoulos, A. T. and Kim, S. K.

Subjects
Mathematics - Numerical Analysis, Computer Science - Distributed, Parallel, and Cluster Computing
Abstract

The Orthomin ( Omin ) and the Generalized Minimal Residual method ( GMRES ) are commonly used iterative methods for approximating the solution of non-symmetric linear systems. The s-step generalizations of these methods enhance their data locality parallel and properties by forming s simultaneous search direction vectors. Good data locality is the key in achieving near peak rates on memory hierarchical supercomputers. The theoretical derivation of the s-step Arnoldi and Omin has been published in the past. Here we derive the s-step GMRES method. We then implement s-step Omin and GMRES on a Cray-2 hierarchical memory supercomputer.

Published
2020

48. Experimental determination of the isospin of $\Lambda_c(2765)^+/\Sigma_c(2765)^+$

Author

The Belle Collaboration, Abdesselam, A., Adachi, I., Adamczyk, K., Ahn, J. K., Aihara, H., Said, S. Al, Arinstein, K., Arita, Y., Asner, D. M., Atmacan, H., Aulchenko, V., Aushev, T., Ayad, R., Aziz, T., Babu, V., Badhrees, I., Bahinipati, S., Bakich, A. M., Ban, Y., Bansal, V., Barberio, E., Barrett, M., Bartel, W., Behera, P., Beleño, C., Belous, K., Bennett, J., Berger, M., Bernlochner, F., Besson, D., Bhardwaj, V., Bhuyan, B., Bilka, T., Biswal, J., Bloomfield, T., Bobrov, A., Bondar, A., Bonvicini, G., Bozek, A., Bračko, M., Braun, N., Breibeck, F., Browder, T. E., Campajola, M., Cao, L., Caria, G., Červenkov, D., Chang, M. -C., Chang, P., Chao, Y., Cheaib, R., Chekelian, V., Chen, A., Chen, K. -F., Chen, Y., Cheon, B. G., Chilikin, K., Chistov, R., Cho, H. E., Cho, K., Chobanova, V., Choi, S. -K., Choi, Y., Choudhury, S., Cinabro, D., Crnkovic, J., Cunliffe, S., Czank, T., Danilov, M., Dash, N., De Nardo, G., Di Carlo, S., Di Capua, F., Dingfelder, J., Doležal, Z., Dong, T. V., Dossett, D., Drȧsal, Z., Drutskoy, A., Dubey, S., Dutta, D., Eidelman, S., Epifanov, D., Fast, J. E., Feindt, M., Ferber, T., Frey, A., Frost, O., Fulsom, B. G., Garg, R., Gaur, V., Gabyshev, N., Garmash, A., Gelb, M., Gemmler, J., Getzkow, D., Giordano, F., Giri, A., Goldenzweig, P., Golob, B., Greenwald, D., Perdekamp, M. Grosse, Grygier, J., Grzymkowska, O., Guan, Y., Guido, E., Guo, H., Haba, J., Hamer, P., Hara, K., Hara, T., Hartbrich, O., Hasegawa, Y., Hasenbusch, J., Hayasaka, K., Hayashii, H., He, X. H., Heck, M., Hedges, M. T., Heffernan, D., Heider, M., Heller, A., Higuchi, T., Hirose, S., Hoshi, Y., Hoshina, K., Hou, W. -S., Hsiung, Y. B., Hsu, C. -L., Huang, K., Huschle, M., Igarashi, Y., Iijima, T., Imamura, M., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Iwata, S., Jacobs, W. W., Jaegle, I., Jang, E. -J., Jeon, H. B., Jia, S., Jin, Y., Joffe, D., Jones, M., Joo, C. W., Joo, K. K., Julius, T., Kahn, J., Kakuno, H., Kaliyar, A. B., Kang, J. H., Kang, K. H., Kapusta, P., Karyan, G., Kataoka, S. U., Kato, Y., Katrenko, P., Kawai, H., Kawasaki, T., Keck, T., Kichimi, H., Kiesling, C., Kim, B. H., Kim, C. H., Kim, D. Y., Kim, H. J., Kim, H. -J., Kim, J. B., Kim, K. T., Kim, S. H., Kim, S. K., Kim, Y. J., Kimmel, T., Kindo, H., Kinoshita, K., Kleinwort, C., Klucar, J., Kobayashi, N., Kodyš, P., Koga, Y., Konno, T., Korpar, S., Kotchetkov, D., Kouzes, R. T., Križan, P., Kroeger, R., Krohn, J. -F., Krokovny, P., Kronenbitter, B., Kuhr, T., Kulasiri, R., Kumar, R., Kumita, T., Kurihara, E., Kuroki, Y., Kuzmin, A., Kvasnička, P., Kwon, Y. -J., Lai, Y. -T., Lalwani, K., Lange, J. S., Lee, I. S., Lee, J. K., Lee, J. Y., Lee, S. C., Leitgab, M., Leitner, R., Levit, D., Lewis, P., Li, C. H., Li, H., Li, L. K., Li, Y., Li, Y. B., Gioi, L. Li, Libby, J., Lieret, K., Limosani, A., Liptak, Z., Liu, C., Liu, Y., Liventsev, D., Loos, A., Louvot, R., Lu, P. -C., Lubej, M., Luo, T., MacNaughton, J., Masuda, M., Matsuda, T., Matvienko, D., McNeil, J. T., Merola, M., Metzner, F., Miyabayashi, K., Miyachi, Y., Miyake, H., Miyata, H., Miyazaki, Y., Mizuk, R., Mohanty, G. B., Mohanty, S., Moon, H. K., Moon, T. J., Mori, T., Morii, T., Moser, H. -G., Mrvar, M., Müller, T., Muramatsu, N., Mussa, R., Nagasaka, Y., Nakahama, Y., Nakamura, I., Nakamura, K. R., Nakano, E., Nakano, T., Nakao, M., Nakayama, H., Nakazawa, H., Nanut, T., Nath, K. J., Natkaniec, Z., Nayak, M., Neichi, K., Ng, C., Niebuhr, C., Niiyama, M., Nisar, N. K., Nishida, S., Nishimura, K., Nitoh, O., Ogawa, A., Ogawa, K., Ogawa, S., Ohshima, T., Okuno, S., Olsen, S. L., Ono, H., Onuki, Y., Oskin, P., Ostrowicz, W., Oswald, C., Ozaki, H., Pakhlov, P., Pakhlova, G., Pal, B., Pang, T., Panzenböck, E., Pardi, S., Park, C. -S., Park, C. W., Park, H., Park, K. S., Park, S. -H., Patra, S., Paul, S., Pavelkin, I., Pedlar, T. K., Peng, T., Pesàntez, L., Pestotnik, R., Peters, M., Piilonen, L. E., Popov, V., Prasanth, K., Prencipe, E., Prim, M. T., Prothmann, K., Purohit, M. V., Rabusov, A., Rauch, J., Reisert, B., Resmi, P. K., Ribežl, E., Ritter, M., Rorie, J., Rostomyan, A., Rozanska, M., Russo, G., Sahoo, D., Sahoo, H., Sakai, Y., Salehi, M., Sandilya, S., Santel, D., Santelj, L., Sanuki, T., Sasaki, J., Sasao, N., Sato, Y., Savinov, V., Schlüter, T., Schneider, O., Schnell, G., Schram, M., Schueler, J., Schwanda, C., Schwartz, A. J., Schwenker, B., Seidl, R., Seino, Y., Semmler, D., Senyo, K., Seon, O., Seong, I. S., Sevior, M. E., Shang, L., Shapkin, M., Shebalin, V., Shen, C. P., Shibata, T. -A., Shibuya, H., Shinomiya, S., Shiu, J. -G., Shwartz, B., Sibidanov, A., Simon, F., Singh, J. B., Sinha, R., Smith, K., Sokolov, A., Soloviev, Y., Solovieva, E., Stanič, S., Starič, M., Steder, M., Stottler, Z., Strube, J. F., Stypula, J., Sugihara, S., Sugiyama, A., Sumihama, M., Sumisawa, K., Sumiyoshi, T., Sutcliffe, W., Suzuki, K., Suzuki, S., Suzuki, S. Y., Takeichi, H., Takizawa, M., Tamponi, U., Tanaka, M., Tanaka, S., Tanida, K., Taniguchi, N., Tao, Y., Taylor, G. N., Tenchini, F., Teramoto, Y., Trabelsi, K., Tsuboyama, T., Uchida, M., Ueda, I., Uehara, S., Uglov, T., Unno, Y., Uno, S., Urquijo, P., Ushiroda, Y., Usov, Y., Vahsen, S. E., Van Hulse, C., Van Tonder, R., Vanhoefer, P., Varner, G., Varvell, K. E., Vervink, K., Vinokurova, A., Vorobyev, V., Vossen, A., Wagner, M. N., Waheed, E., Wang, B., Wang, C. H., Wang, M. -Z., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Watanuki, S., Wedd, R., Wehle, S., Widmann, E., Wiechczynski, J., Williams, K. M., Won, E., Yabsley, B. D., Yamada, S., Yamamoto, H., Yamashita, Y., Yang, S. B., Yashchenko, S., Ye, H., Yelton, J., Yin, J. H., Yook, Y., Yuan, C. Z., Yusa, Y., Zakharov, S., Zhang, C. C., Zhang, J., Zhang, L. M., Zhang, Z. P., Zhao, L., Zhilich, V., Zhukova, V., Zhulanov, V., Zivko, T., Zupanc, A., and Zwahlen, N.

Subjects
High Energy Physics - Experiment
Abstract

We report an experimental determination of the isospin of $\Lambda_c(2765)^+/\Sigma_c(2765)^+$ using 980 fb$^{-1}$ data in the $e^+e^-$ annihilation around $\sqrt{s} = 10.6$ GeV collected by the Belle detector located at the KEKB collider. The isospin partners are searched for in the $\Sigma_c(2455)^{++/0} \pi^{0}$ channels, and no evidence was obtained. Thus the isospin is determined to be zero, and the particle is established to be a $\Lambda_c$., Comment: Conference paper submitted for Hadron2019

Published
2019

49. A Study of NaI(Tl) crystal Encapsulation using Organic scintillators for the Dark Matter Search

Author

Lee, J. Y., Adhikari, G., Ha, C., Kim, H. J., Kim, N. Y., Kim, S. K., Kim, Y. D., and Lee, H. S.

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

Scintillating NaI(Tl) crystals are used for various rare decay experiments, such as dark matter searches. The hygroscopicity of NaI(Tl) crystal makes the construction of crystal detectors in these experiments challenging and requires a tight encapsulation to prevent from air contact. More importantly, in a low radioactivity measurement, identification of external radiations and surface contamination is crucial to characterize the origin of total crystal radioactivities. Studies for NaI(Tl) crystal encapsulation with active organic scintillator vetoes have been performed to mitigate the above-mentioned issues simultaneously. A bare crystal is directly coupled with liquid and plastic scintillators to tag external radiations that penetrate from the outer part of the crystal. We report the pulse shape discrimination for organic scintillator pulses from those of the crystal scintillator in a single detector setup which makes external gammas identifiable and long-term stability tests of the detector setup., Comment: 11 pages, 5 figures

Published
2019
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50. Comparison between DAMA/LIBRA and COSINE-100 in the light of Quenching Factors

Author

Ko, Y. J., Kim, K. W., Adhikari, G., Adhikari, P., de Souza, E. Barbosa, Carlin, N., Choi, J. J., Choi, S., Djamal, M., Ezeribe, A. C., 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, N. Y., Kim, S. K., Kim, Y. D., Kim, Y. H., 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, 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, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Phenomenology, Physics - Instrumentation and Detectors
Abstract

There is a long standing debate about whether or not the annual modulation signal reported by the DAMA/LIBRA collaboration is induced by Weakly Interacting Massive Particles~(WIMP) in the galaxy's dark matter halo scattering from nuclides in their NaI(Tl) crystal target/detector. This is because regions of WIMP-mass vs. WIMP-nucleon cross-section parameter space that can accommodate the DAMA/LIBRA-phase1 modulation signal in the context of the standard WIMP dark matter galactic halo and isospin-conserving~(canonical), spin-independent~(SI) WIMP-nucleon interactions have been excluded by many of other dark matter search experiments including COSINE-100, which uses the same NaI(Tl) target/detector material. Moreover, the recently released DAMA/LIBRA-phase2 results are inconsistent with an interpretation as WIMP-nuclide scattering via the canonical SI interaction and prefer, instead, isospin-violating or spin-dependent interactions. Dark matter interpretations of the DAMA/LIBRA signal are sensitive to the NaI(Tl) scintillation efficiency for nuclear recoils, which is characterized by so-called quenching factors~(QF), and the QF values used in previous studies differ significantly from recently reported measurements, which may have led to incorrect interpretations of the DAMA/LIBRA signal. In this article, the compatibility of the DAMA/LIBRA and COSINE-100 results, in light of the new QF measurements is examined for different possible types of WIMP-nucleon interactions. The resulting allowed parameter space regions associated with the DAMA/LIBRA signal are explicitly compared with 90\% confidence level upper limits from the initial 59.5~day COSINE-100 exposure. With the newly measured QF values, the allowed 3$\sigma$ regions from the DAMA/LIBRA data are still generally excluded by the COSINE-100 data., Comment: Accepted in JCAP

Published
2019
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