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3,289 results on '"Gando, A."'

1. Limits on the Low-Energy Electron Antineutrino Flux from the Brightest GRB of All Time

Author

Araki, T., Chauhan, S., Chiba, K., Eda, T., Eizuka, M., Funahashi, Y., Furuto, A., Gando, A., Gando, Y., Goto, S., Hachiya, T., Hata, K., Ichimura, K., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Marthe, A., Matsumoto, Y., Mitsui, T., Miyake, H., Morita, D., Nakajima, R., Nakamura, K., Nakamura, R., Nakane, J., Ono, T., Ozaki, H., Saito, K., Sakai, T., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Tachibana, K., Tamae, K., Watanabe, H., Watanabe, K., Kurosawa, S., Urano, Y., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Fu, Z., Ghosh, S., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Delloro, S., Odonnell, T., Detwiler, J. A., Enomoto, S., Decowski, M. P., Weerman, K. M., Grant, C., Penek, Ö., Song, H., Li, A., Axani, S. N., Garcia, M., and Sarfraz, M.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The electron antinuetrino flux limits are presented for the brightest gamma-ray burst (GRB) of all time, GRB221009A, over a range of 1.8-200 MeV using the Kamioka Liquid Scintillator Anti Neutrino Detector (KamLAND). Using a variety of time windows to search for electron antineutrinos coincident with the GRB, we set an upper limit on the flux under the assumption of various neutrino source spectra. No excess was observed in any time windows ranging from seconds to days around the event trigger time. The limits are compared to the results presented by IceCube., Comment: 8 pages, 3 figures, 1 table

Published
2024

2. Combined Pre-supernova Alert System with KamLAND and Super-Kamiokande

Author

Abe, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Goto, S, Hachiya, T, Hata, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Koga, M, Kurasawa, M, Mitsui, T, Miyake, H, Morita, D, Nakahata, T, Nakajima, R, Nakamura, K, Nakamura, R, Nakane, J, Ozaki, H, Saito, K, Sakai, T, Shimizu, I, Shirai, J, Shiraishi, K, Shoji, R, Suzuki, A, Takeuchi, A, Tamae, K, Watanabe, H, Watanabe, K, Yoshida, S, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Fu, Z, Smolsky, J, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Dell’Oro, S, O’Donnell, T, Detwiler, JA, Enomoto, S, Decowski, MP, Weerman, KM, Grant, C, Song, H, Li, A, Axani, SN, Garcia, M, Collaboration, The KamLAND, Abe, K, Bronner, C, Hayato, Y, Hiraide, K, Hosokawa, K, Ieki, K, Ikeda, M, Kameda, J, Kanemura, Y, Kaneshima, R, Kashiwagi, Y, Kataoka, Y, Miki, S, Mine, S, Miura, M, Moriyama, S, Nakahata, M, Nakano, Y, Nakayama, S, Noguchi, Y, Sato, K, Sekiya, H, Shiba, H, Shimizu, K, Shiozawa, M, Sonoda, Y, Suzuki, Y, Takeda, A, Takemoto, Y, Tanaka, H, Yano, T, and Han, S

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics, Astronomical sciences, Particle and high energy physics, Space sciences
Abstract

Preceding a core-collapse supernova (CCSN), various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande (SK) via inverse beta decay interactions. Once these pre-supernova (pre-SN) neutrinos are observed, an early warning of the upcoming CCSN can be provided. In light of this, KamLAND and SK, both located in the Kamioka mine in Japan, have been monitoring pre-SN neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and SK on pre-SN neutrino detection. A pre-SN alert system combining the KamLAND detector and the SK detector was developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-SN neutrino signal from a 15 M ⊙ star within 510 pc of the Earth at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hr in advance.

Published
2024

3. Search for Majorana Neutrinos with the Complete KamLAND-Zen Dataset

Author

Abe, S., Araki, T., Chiba, K., Eda, T., Eizuka, M., Funahashi, Y., Furuto, A., Gando, A., Gando, Y., Goto, S., Hachiya, T., Hata, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Marthe, A., Matsumoto, Y., Mitsui, T., Miyake, H., Morita, D., Nakajima, R., Nakamura, K., Nakamura, R., Nakane, J., Ono, T., Ozaki, H., Saito, K., Sakai, T., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Tachibana, K., Tamae, K., Watanabe, H., Watanabe, K., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Fu, Z., Ghosh, S., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Dell'Oro, S., O'Donnell, T., Detwiler, J. A., Enomoto, S., Decowski, M. P., Weerman, K. M., Grant, C., Penek, O., Song, H., Li, A., Axani, S. N., Garcia, M., and Sarfraz, M.

Subjects
High Energy Physics - Experiment
Abstract

We present a search for neutrinoless double-beta ($0\nu\beta\beta$) decay of $^{136}$Xe using the full KamLAND-Zen 800 dataset with 745 kg of enriched xenon, corresponding to an exposure of $2.097$ ton yr of $^{136}$Xe. This updated search benefits from a more than twofold increase in exposure, recovery of photo-sensor gain, and reduced background from muon-induced spallation of xenon. Combining with the search in the previous KamLAND-Zen phase, we obtain a lower limit for the $0\nu\beta\beta$ decay half-life of $T_{1/2}^{0\nu} > 3.8 \times 10^{26}$ yr at 90% C.L., a factor of 1.7 improvement over the previous limit. The corresponding upper limits on the effective Majorana neutrino mass are in the range 28-122 meV using phenomenological nuclear matrix element calculations., Comment: arXiv admin note: text overlap with arXiv:2203.02139

Published
2024

4. Search for charged excited states of dark matter with KamLAND-Zen

Author

Abe, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Goto, S, Hachiya, T, Hata, K, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Koga, M, Kurasawa, M, Mitsui, T, Miyake, H, Morita, D, Nakahata, T, Nakajima, R, Nakamura, K, Nakamura, R, Nakane, J, Ozaki, H, Sakai, T, Shimizu, I, Shirai, J, Shiraishi, K, Shoji, R, Suzuki, A, Takeuchi, A, Tamae, K, Watanabe, H, Watanabe, K, Obara, S, Yoshida, S, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Ichikawa, A, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Fu, Z, Smolsky, J, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Dell'Oro, S, O'Donnell, T, Detwiler, JA, Enomoto, S, Decowski, MP, Weerman, KM, Grant, C, Li, A, and Song, H

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Dark matter, Organic liquid scintillator, Xenon, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract

Particle dark matter could belong to a multiplet that includes an electrically charged state. WIMP dark matter (χ0) accompanied by a negatively charged excited state (χ−) with a small mass difference (e.g. < 20 MeV) can form a bound-state with a nucleus such as xenon. This bound-state formation is rare and the released energy is O(1−10) MeV depending on the nucleus, making large liquid scintillator detectors suitable for detection. We searched for bound-state formation events with xenon in two experimental phases of the KamLAND-Zen experiment, a xenon-doped liquid scintillator detector. No statistically significant events were observed. For a benchmark parameter set of WIMP mass mχ0=1 TeV and mass difference Δm=17 MeV, we set the most stringent upper limits on the recombination cross section times velocity 〈σv〉 and the decay-width of χ− to 9.2×10−30 cm3/s and 8.7×10−14 GeV, respectively at 90% confidence level.

Published
2024

5. Combined Pre-Supernova Alert System with Kamland and Super-Kamiokande

Author

KamLAND, Collaborations, Super-Kamiokande, Abe, Seisho, Eizuka, Minori, Futagi, Sawako, Gando, Azusa, Gando, Yoshihito, Goto, Shun, Hachiya, Takahiko, Hata, Kazumi, Ichimura, Koichi, Ieki, Sei, Ikeda, Haruo, Inoue, Kunio, Ishidoshiro, Koji, Kamei, Yuto, Kawada, Nanami, Kishimoto, Yasuhiro, Koga, Masayuki, Kurasawa, Maho, Mitsui, Tadao, Miyake, Haruhiko, Morita, Daisuke, Nakahata, Takeshi, Nakajima, Rika, Nakamura, Kengo, Nakamura, Rikuo, Nakamura, Ryo, Nakane, Jun, Ozaki, Hideyoshi, Saito, Keita, Sakai, Taichi, Shimizu, Itaru, Shirai, Junpei, Shiraishi, Kensuke, Shoji, Ryunosuke, Suzuki, Atsuto, Takeuchi, Atsuto, Tamae, Kyoko, Watanabe, Hiroko, Watanabe, Kazuho, Yoshida, Sei, Umehara, Saori, Fushimi, Ken-Ichi, Kotera, Kenta, Urano, Yusuke, Berger, Bruce E., Fujikawa, Brian K., Larned, John G., Maricic, Jelena, Fu, Zhenghao, Smolsky, Joseph, Winslow, Lindley A., Efremenko, Yuri, Karwowski, Hugon J., Markoff, Diane M., Tornow, Werner, Dell'Oro, Stefano, O'Donnell, Thomas, Detwiler, Jason A., Enomoto, Sanshiro, Decowski, Michal P., Weerman, Kelly M., Grant, Christopher, Song, Hasung, Li, Aobo, Axani, Spencer N., Garcia, Miles, Abe, Ko, Bronner, Christophe, Hayato, Yoshinari, Hiraide, Katsuki, Hosokawa, Keishi, Ieki, Kei, Ikeda, Motoyasu, Kameda, June, Kanemura, Yuki, Kaneshima, Ryota, Kashiwagi, Yuri, Kataoka, Yousuke, Miki, Shintaro, Mine, Shunichi, Miura, Makoto, Moriyama, Shigetaka, Nakahata, Masayuki, Nakano, Yuuki, Nakayama, Shoei, Noguchi, Yohei, Sato, Kazufumi, Sekiya, Hiroyuki, Shiba, Hayato, Shimizu, Kotaro, Shiozawa, Masato, Sonoda, Yutaro, Suzuki, Yoichiro, Takeda, Atsushi, Takemoto, Yasuhiro, Tanaka, Hidekazu K., Yano, Takatomi, Han, Seungho, Kajita, Takaaki, Okumura, Kimihiro, Tashiro, Takuya, Tomiya, Takuya, Wang, Xubin, Yoshida, Shunsuke, Fernandez, Pablo, Labarga, Luis, Ospina, Nataly, Zaldivar, Bryan, Pointon, Barry W., Kearns, Edward, Raaf, Jennifer L., Wan, Linyan, Wester, Thomas, Bian, Jianming, Griskevich, Jeff, Smy, Michael B., Sobel, Henry W., Takhistov, Volodymyr, Yankelevich, Alejandro, Hill, James, Jang, MinCheol, Lee, Seonghak, Moon, DongHo, Park, RyeongGyoon, Bodur, Baran, Scholberg, Kate, Walter, Chris W., Beauchêne, Antoine, Drapier, Olivier, Giampaolo, Alberto, Mueller, Thomas A., Santos, Andrew D., Paganini, Pascal, Quilain, Benjamin, Rogly, Rudolph, Nakamura, Taku, Jang, Jee-Seung, Machado, Lucas N., Learned, John G., Choi, Koun, Iovine, Nadege, Cao, Son V., Anthony, Lauren H. V., Martin, Daniel G. R., Prouse, Nick W., Scott, Mark, Uchida, Yoshi, Berardi, Vincenzo, Calabria, Nicola F., Catanesi, M. G., Radicioni, Emilio, Langella, Aurora, de Rosa, Gianfranca, Collazuol, Gianmaria, Feltre, Matteo, Iacob, Fabio, Mattiazzi, Marco, Ludovici, Lucio, Gonin, Michel, Périssé, Lorenzo, Pronost, Guillaume, Fujisawa, Chiori, Horiuchi, Shogo, Kobayashi, Misaki, Liu, Yu-Ming, Maekawa, Yuto, Nishimura, Yasuhiro, Okazaki, Reo, Akutsu, Ryosuke, Friend, Megan, Hasegawa, Takuya, Ishida, Taku, Kobayashi, Takashi, Jakkapu, Mahesh, Matsubara, Tsunayuki, Nakadaira, Takeshi, Nakamura, Kenzo, Oyama, Yuichi, Sakashita, Ken, Sekiguchi, Tetsuro, Tsukamoto, Toshifumi, Yrey, Antoniosk Portocarrero, Bhuiyan, Nahid, Burton, George T., Di Lodovico, Francesca, Gao, Joanna, Goldsack, Alexander, Katori, Teppei, Migenda, Jost, Ramsden, Rory M., Xie, Zhenxiong, Zsoldos, Stephane, Suzuki, Atsumu T., Takagi, Yusuke, Takeuchi, Yasuo, Zhong, Haiwen, Feng, Jiahui, Feng, Li-Cheng, Hu, Jianrun, Hu, Zhuojun, Kawaue, Masaki, Kikawa, Tatsuya, Mori, Masamitsu, Nakaya, Tsuyoshi, Wendell, Roger A., Yasutome, Kenji, Jenkins, Sam J., McCauley, Neil K., Mehta, Pruthvi, Tarrant, Adam, Wilking, Mike J., Fukuda, Yoshiyuki, Itow, Yoshitaka, Menjo, Hiroaki, Ninomiya, Kotaro, Yoshioka, Yushi, Lagoda, Justyna, Mandal, Maitrayee, Mijakowski, Piotr, Prabhu, Yashwanth S., Zalipska, Joanna, Jia, Mo, Jiang, Junjie, Shi, Wei, Yanagisawa, Chiaki, Harada, Masayuki, Hino, Yota, Ishino, Hirokazu, Koshio, Yusuke, Nakanishi, Fumi, Sakai, Seiya, Tada, Tomoaki, Tano, Tomohiro, Ishizuka, Takeharu, Barr, Giles, Barrow, Daniel, Cook, Laurence, Samani, Soniya, Wark, David, Holin, Anna, Nova, Federico, Jung, Seunghyun, Yang, Byeongsu, Yang, JeongYeol, Yoo, Jonghee, Fannon, Jack E. P., Kneale, Liz, Malek, Matthew, McElwee, Jordan M., Thiesse, Matthew D., Thompson, Lee F., Wilson, Stephen T., Okazawa, Hiroko, Mohan, Lakshmi S., Kim, SooBong, Kwon, Eunhyang, Seo, Ji-Woong, Yu, Intae, Ichikawa, Atsuko K., Nakamura, Kiseki D., Tairafune, Seidai, Nishijima, Kyoshi, Eguchi, Aoi, Nakagiri, Kota, Nakajima, Yasuhiro, Shima, Shizuka, Taniuchi, Natsumi, Watanabe, Eiichiro, Yokoyama, Masashi, de Perio, Patrick, Fujita, Saki, Jesus-Valls, Cesar, Martens, Kai, Tsui, Ka M., Vagins, Mark R., Xia, Junjie, Izumiyama, Shota, Kuze, Masahiro, Matsumoto, Ryo, Terada, Kotaro, Asaka, Ryusei, Ishitsuka, Masaki, Ito, Hiroshi, Ommura, Yuga, Shigeta, Natsuki, Shinoki, Masataka, Yamauchi, Koki, Yoshida, Tsukasa, Gaur, Rhea, Gousy-Leblan, Vincent, Hartz, Mark, Konaka, Akira, Li, Xiaoyue, Chen, Shaomin, Xu, Benda, Zhang, Aiqiang, Zhang, Bin, Posiadala-Zezula, Magdalena, Boyd, Steven B., Edwards, Rory, Hadley, David, Nicholson, Matthew, O'Flaherty, Marcus, Richards, Benjamin, Ali, Ajmi, Jamieson, Blair, Amanai, Shogo, Marti-Magro, Lluis, Minamino, Akihiro, Shibayama, Ryo, and Suzuki, Serina

Subjects
High Energy Physics - Experiment, Astrophysics - High Energy Astrophysical Phenomena, Physics - Instrumentation and Detectors
Abstract

Preceding a core-collapse supernova, various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande via inverse beta decay interactions. Once these pre-supernova neutrinos are observed, an early warning of the upcoming core-collapse supernova can be provided. In light of this, KamLAND and Super-Kamiokande, both located in the Kamioka mine in Japan, have been monitoring pre-supernova neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and Super-Kamiokande on pre-supernova neutrino detection. A pre-supernova alert system combining the KamLAND detector and the Super-Kamiokande detector was developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-supernova neutrino signal from a 15 M$_{\odot}$ star within 510 pc of the Earth, at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hours in advance., Comment: Resubmitted to ApJ. 22 pages, 16 figures, for more information about the combined pre-supernova alert system, see https://www.lowbg.org/presnalarm/

Published
2024
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6. Development of a method to measure trace level of uranium and thorium in scintillation films

Author

Ichimura, K., Chiba, K., Gando, Y., Ikeda, H., Kishimoto, Y., Kurasawa, M., Nemoto, K., Sakaguchi, A., Takaku, Y., and Sakakieda, Y.

Subjects
Physics - Instrumentation and Detectors
Abstract

We have established a method to measure picograms-per-gram (pg g$^{-1}$) levels of $^{238}$U and $^{232}$Th in scintillation films by combining the dry ashing method and inductively coupled plasma mass spectrometry. Trace amounts of $^{238}$U and $^{232}$Th were measured in up to 2~g of the scintillation film with almost 100% collection efficiency. This paper details the experimental procedure, including the pretreatment of the samples and labware, detection limit of the method, collection efficiencies of $^{238}$U and $^{232}$Th, and measurement of $^{238}$U and $^{232}$Th in a polyethylene naphthalate film. This method is also applicable to $^{238}$U and $^{232}$Th measurements in other low-background organic materials for rare event search experiments.

Published
2024
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8. Search for Charged Excited States of Dark Matter with KamLAND-Zen

Author

collaboration, KamLAND-Zen, Abe, S., Eizuka, M., Futagi, S., Gando, A., Gando, Y., Goto, S., Hachiya, T., Hata, K., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Kurasawa, M., Mitsui, T., Miyake, H., Morita, D., Nakahata, T., Nakajima, R., Nakamura, K., Nakamura, R., Nakane, J., Ozaki, H., Sakai, T., Shimizu, I., Shirai, J., Shiraishi, K., Shoji, R., Suzuki, A., Takeuchi, A., Tamae, K., Watanabe, H., Watanabe, K., Obara, S., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Ichikawa, A. K., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Fu, Z., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Dell'Oro, S., O'Donnell, T., Detwiler, J. A., Enomoto, S., Decowski, M. P., Weerman, K. M., Grant, C., Li, A., and Song, H.

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

Particle dark matter could belong to a multiplet that includes an electrically charged state. WIMP dark matter ($\chi^{0}$) accompanied by a negatively charged excited state ($\chi^{-}$) with a small mass difference (e.g. $<$ 20 MeV) can form a bound-state with a nucleus such as xenon. This bound-state formation is rare and the released energy is $\mathcal{O}(1-10$) MeV depending on the nucleus, making large liquid scintillator detectors suitable for detection. We searched for bound-state formation events with xenon in two experimental phases of the KamLAND-Zen experiment, a xenon-doped liquid scintillator detector. No statistically significant events were observed. For a benchmark parameter set of WIMP mass $m_{\chi^{0}} = 1$ TeV and mass difference $\Delta m = 17$ MeV, we set the most stringent upper limits on the recombination cross section times velocity $\langle\sigma v\rangle$ and the decay-width of $\chi^{-}$ to $9.2 \times 10^{-30}$ ${\rm cm^3/s}$ and $8.7 \times 10^{-14}$ GeV, respectively at 90% confidence level.

Published
2023
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9. First Study of the PIKACHU Project: Development and Evaluation of High-Purity Gd$_3$Ga$_3$Al$_2$O$_{12}$:Ce Crystals for $^{160}$Gd Double Beta Decay Search

Author

Omori, Takumi, Iida, Takashi, Gando, Azusa, Hosokawa, Keishi, Kamada, Kei, Mizukoshi, Keita, Shoji, Yasuhiro, Yoshino, Masao, Fushimi, Ken-Ichi, Suzuki, Hisanori, and Takahashi, Kotaro

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

Uncovering neutrinoless double beta decay (0$\nu$2$\beta$) is crucial for confirming neutrinos' Majorana characteristics. The decay rate of 0$\nu\beta\beta$ is theoretically uncertain, influenced by nuclear matrix elements that vary across nuclides. To reduce this uncertainty, precise measurement of the half-life of neutrino-emitting double beta decay (2$\nu$2$\beta$) in different nuclides is essential. We have launched the PIKACHU (Pure Inorganic scintillator experiment in KAmioka for CHallenging Underground sciences) project to fabricate high-purity Ce-doped Gd$_{3}$Ga$_{3}$Al$_{2}$O$_{12}$ (GAGG) single crystals and use them to study the double beta decay of $^{160}$Gd. Predictions from two theoretical models on nuclear matrix element calculations for 2$\nu$2$\beta$ in $^{160}$Gd show a significant discrepancy in estimated half-lives, differing by approximately an order of magnitude. If the lower half-life estimation holds true, detecting 2$\nu$2$\beta$ in $^{160}$Gd could be achievable with a sensitivity enhancement slightly more than an order of magnitude compared to prior investigations using Ce-doped Gd$_2$SiO$_5$ (GSO) crystal. We have successfully developed GAGG crystals with purity levels surpassing previous standards through refined purification and selection of raw materials. Our experiments with these crystals indicate the feasibility of reaching sensitivities exceeding those of earlier studies. This paper discusses the ongoing development and scintillator performance evaluation of High-purity GAGG crystals, along with the anticipated future prospects of the PIKACHU experiment., Comment: 19 pages, 10 figures

Published
2024

10. Language Choice in Official Information Materials on COVID-19 in the Philippines: A Language Justice Perspective

Author

Edward Jay M. Quinto, Angela Cailou E. Gando, Anicia Mae Nantin, and Maxine Jecri S. Novilla

Abstract

Every individual's language rights are just as important and, often, even equate to healthcare rights during the COVID-19 pandemic. During this crisis, essential and lifesaving information and updates about local and international efforts to respond to and mitigate the impacts of the pandemic have to be made available using language(s) accessible and understandable to as many groups of people as possible. Using the lens of language justice, this paper analysed 238 official - information materials on COVID-19 from social media pages of the Department of Health (DOH) regional offices in hopes of unpacking the injustice that those who speak minor languages in multilingual Philippines experience. The hegemonic presence of major languages in the materials was observed as a majority of the information materials were published in Tagalog and English, whereas the Mother Tongues were unequally represented. The researchers argue that more Filipinos are at risk of contracting the virus, as the languages in which lifesaving information are presented are limited and unequal. Autonomy and decentralisation of local government offices and representation of speakers of the minority languages in the production and publication of materials will be an inclusive, sustainable, and participatory community approach to COVID-19 as a language rights emergency.

Published
2024
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11. Development of a low-background HPGe detector at Kamioka Observatory

Author

Ichimura, K., Ikeda, H., Kishimoto, Y., Kurasawa, M., Suzuki, A. A., Gando, Y., Ikeda, M., Hosokawa, K., Sekiya, H., Ito, H., Minamino, A., and Suzuki, S.

Subjects
Physics - Instrumentation and Detectors
Abstract

A new ultra-low background high-purity germanium (HPGe) detector has been installed at the Kamioka underground experimental site. The background count rate in the energy range from 40 keV to 2700 keV is about 25% lower than that of the first HPGe detector installed in 2016, which has the same detector specification and similar shielding geometry. This paper describes the shielding configuration, including the cleaning of the material surface, the comparison of calibration data and simulation, the time variation of the background spectra, the sample measurement procedure, and some results of the radioactivity in the selected samples.

Published
2023
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12. Measurement of cosmic-ray muon spallation products in a xenon-loaded liquid scintillator with KamLAND

Author

Collaboration, KamLAND-Zen, Abe, S., Asami, S., Eizuka, M., Futagi, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Kurasawa, M., Mitsui, T., Miyake, H., Nakahata, T., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Fu, Z., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Dell'Oro, S., O'Donnell, T., Detwiler, J. A., Enomoto, S., Decowski, M. P., Weerman, K., Grant, C., Li, A., and Song, H.

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

Cosmic-ray muons produce various radioisotopes when passing through material. These spallation products can be backgrounds for rare event searches such as in solar neutrino, double-beta decay, and dark matter search experiments. The KamLAND-Zen experiment searches for neutrinoless double-beta decay in 745kg of xenon dissolved in liquid scintillator. The experiment includes dead-time-free electronics with a high efficiency for detecting muon-induced neutrons. The production yields of different radioisotopes are measured with a combination of delayed coincidence techniques, newly developed muon reconstruction and xenon spallation identification methods. The observed xenon spallation products are consistent with results from the FLUKA and Geant4 simulation codes.

Published
2023

15. Measurement of cosmic-ray muon spallation products in a xenon-loaded liquid scintillator with KamLAND

Author

Abe, S, Asami, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Koga, M, Kurasawa, M, Mitsui, T, Miyake, H, Nakahata, T, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Yoshida, S, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Fu, Z, Smolsky, J, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Dell'Oro, S, O'Donnell, T, Detwiler, JA, Enomoto, S, Decowski, MP, Weerman, KM, Grant, C, Li, A, and Song, H

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Nuclear and plasma physics
Abstract

Cosmic-ray muons produce various radioisotopes when passing through material. These spallation products can be backgrounds for rare event searches such as in solar neutrino, double-β decay, and dark matter search experiments. The KamLAND-Zen experiment searches for neutrinoless double-β decay in 745 kg of xenon dissolved in liquid scintillator. The experiment includes dead-time-free electronics with a high efficiency for detecting muon-induced neutrons. The production yields of different radioisotopes are measured with a combination of delayed coincidence techniques, newly developed muon reconstruction, and xenon spallation identification methods. The observed xenon spallation products are consistent with results from the fluka and geant4 simulation codes.

Published
2023

16. First measurement of the strange axial coupling constant using neutral-current quasielastic interactions of atmospheric neutrinos at KamLAND

Author

Abe, S, Asami, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Koga, M, Kurasawa, M, Mitsui, T, Miyake, H, Nakahata, T, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Yoshida, S, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Fu, Z, Smolsky, J, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, Li, A, Song, H, Dell’Oro, S, and O’Donnell, T

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Astronomical sciences, Particle and high energy physics
Abstract

We report a measurement of the strange axial coupling constant gAs using atmospheric neutrino data at KamLAND. This constant is a component of the axial form factor of the neutral-current quasielastic (NCQE) interaction. The value of gAs significantly changes the ratio of proton and neutron NCQE cross sections. KamLAND is suitable for measuring NCQE interactions as it can detect nucleon recoils with low-energy thresholds and measure neutron multiplicity with high efficiency. KamLAND data, including the information on neutron multiplicity associated with the NCQE interactions, makes it possible to measure gAs with a suppressed dependence on the axial mass MA, which has not yet been determined. For a comprehensive prediction of the neutron emission associated with neutrino interactions, we establish a simulation of particle emission via nuclear deexcitation of C12, a process not considered in existing neutrino Monte Carlo event generators. Energy spectrum fitting for each neutron multiplicity gives gAs=-0.14-0.26+0.25, which is the most stringent limit obtained using NCQE interactions without MA constraints. The two-body current contribution considered in this analysis relies on a theoretically effective model and electron scattering experiments and requires future verification by direct measurements and future model improvement.

Published
2023

17. First measurement of the strange axial coupling constant using neutral-current quasielastic interactions of atmospheric neutrinos at KamLAND

Author

KamLAND Collaboration, Abe, S., Asami, S., Eizuka, M., Futagi, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Kurasawa, M., Mitsui, T., Miyake, H., Nakahata, T., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Fu, Z., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Li, A., Song, H., Dell'Oro, S., and O'Donnell, T.

Subjects
High Energy Physics - Experiment
Abstract

We report a measurement of the strange axial coupling constant $g_A^s$ using atmospheric neutrino data at KamLAND. This constant is a component of the axial form factor of the neutral-current quasielastic (NCQE) interaction. The value of $g_A^s$ significantly changes the ratio of proton and neutron NCQE cross sections. KamLAND is suitable for measuring NCQE interactions as it can detect nucleon recoils with low-energy thresholds and measure neutron multiplicity with high efficiency. KamLAND data, including the information on neutron multiplicity associated with the NCQE interactions, makes it possible to measure $g_A^s$ with a suppressed dependence on the axial mass $M_A$, which has not yet been determined. For a comprehensive prediction of the neutron emission associated with neutrino interactions, we establish a simulation of particle emission via nuclear deexcitation of $^{12}$C, a process not considered in existing neutrino Monte Carlo event generators. Energy spectrum fitting for each neutron multiplicity gives $g_A^s =-0.14^{+0.25}_{-0.26}$, which is the most stringent limit obtained using NCQE interactions without $M_A$ constraints. The two-body current contribution considered in this analysis relies on a theoretically effective model and electron scattering experiments and requires future verification by direct measurements and future model improvement.

Published
2022
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18. Cardiorespiratory fitness and body mass index on metabolic syndrome in middle-aged Japanese adults under national health guidance: a cross-sectional study

Author

Xiangyu Zhai, Susumu S. Sawada, Sayaka Kurosawa, Sakura Koriyama, Serena A. Dimitroff, Shinji Sato, Yuko Oguma, Yoshio Nakata, Kazushi Maruo, Motohiko Miyachi, Yuko Gando, Koichiro Oka, and Duck-chul Lee

Subjects
Cardiorespiratory fitness, Body mass index, Metabolic syndrome, Epidemiology, Public aspects of medicine, RA1-1270
Abstract

Abstract Objectives Poor cardiorespiratory fitness (CRF) and high body mass index (BMI) increased the risk of developing metabolic Syndrome (MetS) mostly in Caucasians. However, the sex-specific combined association of CRF and BMI on MetS considering health-related behaviors has yet to be thoroughly examined in Japanese. This study aims to investigate the sex-specific independent and combined associations of CRF and BMI with MetS in middle-aged Japanese adults. Methods 421 participants were included in this cross-sectional study. CRF was estimated using a submaximal cycle ergometer. CRF and BMI were respectively divided into three categories according to tertile distribution. MetS was diagnosed based on five risk factors: waist circumference, triglycerides, high-density lipoprotein cholesterol, blood pressure, and fasting glucose. Multivariable logistic regression models were used to estimate independent and combined association of CRF and BMI with MetS. Results Results showed that 154 (57.5%) and 70 (45.8%) of men and women had MetS, respectively. Compared to men with lower CRF or higher BMI, men with middle and higher CRF or middle and lower BMI were less likely to have MetS. Compared with ‘unfit and higher BMI’ group, ‘unfit and lower BMI’, ‘fit and higher BMI’, and ‘fit and lower BMI’ groups in men showed statistically significant decreased prevalences of MetS. However, no significant associations were found in women. Conclusions This study found significant independent and combined associations of CRF and BMI with MetS only in men, but not in women. However, prospective studies are warranted to confirm sex-specific associations of CRF and BMI with MetS.

Published
2024
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19. Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen

Author

Abe, S, Asami, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hayashida, S, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Koga, M, Kurasawa, M, Maemura, N, Mitsui, T, Miyake, H, Nakahata, T, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Ueshima, K, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Chernyak, D, Kozlov, A, Nakamura, KZ, Yoshida, S, Takemoto, Y, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Smolsky, J, Fu, Z, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Dell'Oro, S, O'Donnell, T, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, Li, A, and Song, H

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, KamLAND-Zen Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νββ) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>2.3×10^{26}  yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations.

Published
2023

20. Search for charged excited states of dark matter with KamLAND-Zen

Author

S. Abe, M. Eizuka, S. Futagi, A. Gando, Y. Gando, S. Goto, T. Hachiya, K. Hata, K. Hosokawa, K. Ichimura, S. Ieki, H. Ikeda, K. Inoue, K. Ishidoshiro, Y. Kamei, N. Kawada, Y. Kishimoto, M. Koga, M. Kurasawa, T. Mitsui, H. Miyake, D. Morita, T. Nakahata, R. Nakajima, K. Nakamura, R. Nakamura, J. Nakane, H. Ozaki, T. Sakai, I. Shimizu, J. Shirai, K. Shiraishi, R. Shoji, A. Suzuki, A. Takeuchi, K. Tamae, H. Watanabe, K. Watanabe, S. Obara, S. Yoshida, S. Umehara, K. Fushimi, K. Kotera, Y. Urano, A. Ichikawa, B.E. Berger, B.K. Fujikawa, J.G. Learned, J. Maricic, S.N. Axani, Z. Fu, J. Smolsky, L.A. Winslow, Y. Efremenko, H.J. Karwowski, D.M. Markoff, W. Tornow, S. Dell'Oro, T. O'Donnell, J.A. Detwiler, S. Enomoto, M.P. Decowski, K.M. Weerman, C. Grant, A. Li, and H. Song

Subjects
Dark matter, Organic liquid scintillator, Xenon, Physics, QC1-999
Abstract

Particle dark matter could belong to a multiplet that includes an electrically charged state. WIMP dark matter (χ0) accompanied by a negatively charged excited state (χ−) with a small mass difference (e.g. < 20 MeV) can form a bound-state with a nucleus such as xenon. This bound-state formation is rare and the released energy is O(1−10) MeV depending on the nucleus, making large liquid scintillator detectors suitable for detection. We searched for bound-state formation events with xenon in two experimental phases of the KamLAND-Zen experiment, a xenon-doped liquid scintillator detector. No statistically significant events were observed. For a benchmark parameter set of WIMP mass mχ0=1 TeV and mass difference Δm=17 MeV, we set the most stringent upper limits on the recombination cross section times velocity 〈σv〉 and the decay-width of χ− to 9.2×10−30 cm3/s and 8.7×10−14 GeV, respectively at 90% confidence level.

Published
2024
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22. Extraction of Moringa oleifera Leaves to Obtain Antioxidants and Vitamins

Author

Gomes, Olívia, Leitão, Anabela, de Sousa, Hermínio C., Braga, Mara, Gando-Ferreira, Licínio, Bezaeva, Natalia S., Series Editor, Gomes Coe, Heloisa Helena, Series Editor, Nawaz, Muhammad Farrakh, Series Editor, Galvão, João Rafael da Costa Sanches, editor, Brito, Paulo, editor, Neves, Filipe dos Santos, editor, Almeida, Henrique de Amorim, editor, Mourato, Sandra de Jesus Martins, editor, and Nobre, Catarina, editor

Published
2024
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23. Abundances of uranium and thorium elements in Earth estimated by geoneutrino spectroscopy

Author

Abe, S., Asami, S., Eizuka, M., Futagi, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Kurasawa, M., Maemura, N., Mitsui, T., Miyake, H., Nakahata, T., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirahata, Y., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Fu, Z., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Song, H., O'Donnell, T., and Dell'Oro, S.

Subjects
Physics - Geophysics, High Energy Physics - Experiment
Abstract

The decay of the primordial isotopes $^{238}\mathrm{U}$, $^{235}\mathrm{U}$, $^{232}\mathrm{Th}$, and $^{40}\mathrm{K}$ have contributed to the terrestrial heat budget throughout the Earth's history. Hence the individual abundance of those isotopes are key parameters in reconstructing contemporary Earth model. The geoneutrinos produced by the radioactive decays of uranium and thorium have been observed with the Kamioka Liquid-Scintillator Antineutrino Detector (KamLAND). Those measurements have been improved with more than 18-year observation time, and improvements in detector background levels mainly by an 8-year almost rector-free period now permit spectroscopy with geoneutrinos. Our results yield the first constraint on both uranium and thorium heat contributions. Herein the KamLAND result is consistent with geochemical estimations based on elemental abundances of chondritic meteorites and mantle peridotites. The High-Q model is disfavored at 99.76% C.L. and a fully radiogenic model is excluded at 5.2$\sigma$ assuming a homogeneous heat producing element distribution in the mantle., Comment: 13 pages, 2 figures, accepted for publication in Geophysical Research Letters on Aug 4th, 2022

Published
2022
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24. Search for supernova neutrinos and constraint on the galactic star formation rate with the KamLAND data

Author

Abe, S., Asami, S., Eizuka, M., Futagi, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Kurasawa, M., Maemura, N., Mitsui, T., Miyake, H., Nakahata, T., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Winslow, L. A., Fu, Z., Smolsky, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Song, H., O'Donnell, T., and Dell'Oro, S.

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

We present the results of a search for core-collapse supernova neutrinos, using long-term KamLAND data from 2002 March 9 to 2020 April 25. We focus on the electron antineutrinos emitted from supernovae in the energy range of 1.8--111 MeV. Supernovae will make a neutrino event cluster with the duration of $\sim$10 s in the KamLAND data. We find no neutrino clusters and give the upper limit on the supernova rate as to be 0.15 yr$^{-1}$ with a 90% confidence level. The detectable range, which corresponds to a >95% detection probability, is 40--59 kpc and 65--81 kpc for core-collapse supernovae and failed core-collapse supernovae, respectively. This paper proposes to convert the supernova rate obtained by the neutrino observation to the Galactic star formation rate. Assuming a modified Salpeter-type initial mass function, the upper limit on the Galactic star formation rate is <(17.5--22.7) $M_{\odot} \mathrm{yr}^{-1}$ with a 90% confidence level., Comment: 10 pages, 4 figures, accepted for publication in Astrophysical Journal

Published
2022
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25. Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen

Author

Collaboration, KamLAND-Zen, Abe, S., Asami, S., Eizuka, M., Futagi, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Kurasawa, M., Maemura, N., Mitsui, T., Miyake, H., Nakahata, T., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Chernyak, D., Kozlov, A., Nakamura, K. Z., Yoshida, S., Takemoto, Y., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Smolsky, J., Fu, Z., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Dell'Oro, S., O'Donnell, T., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Li, A., and Song, H.

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

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta ($0\nu\beta\beta$) decay half-life in $^{136}$Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of $^{136}$Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the $0\nu\beta\beta$ decay half-life of $T_{1/2}^{0\nu} > 2.3 \times 10^{26}$ yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations., Comment: 7 pages, 3 figures

Published
2022
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26. KamLAND’s search for correlated low-energy electron antineutrinos with astrophysical neutrinos from IceCube

Author

Abe, S, Asami, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Kinoshita, T, Koga, M, Kurasawa, M, Maemura, N, Mitsui, T, Miyake, H, Nakahata, T, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Yoshida, S, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Smolsky, J, Lertprasertpong, J, Winslow, LA, Fu, Z, Ouellet, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Li, A, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, Song, H, O’Donnell, T, and Dell’Oro, S

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Neutrinos, Astrophysical neutrinos, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Astronomical sciences, Particle and high energy physics
Abstract

We report the results of a search for MeV-scale astrophysical neutrinos in KamLAND presented as an excess in the number of coincident neutrino interactions associated with the publicly available high-energy neutrino datasets from the IceCube Neutrino Observatory. We find no statistically significant excess in the number of observed low-energy electron antineutrinos in KamLAND, given a coincidence time window of ±500 s, ±1,000 s, ±3,600 s, and ±10,000 s around each of the IceCube neutrinos. We use this observation to present limits from 1.8 MeV to 100 MeV on the electron antineutrino fluence, assuming a mono-energetic flux. We then compare the results to several astrophysical measurements performed by IceCube and place a limit at the 90% confidence level on the electron antineutrino isotropic thermal luminosity from the TXS 0506+056 blazar.

Published
2022

27. KamLAND's search for correlated low-energy electron antineutrinos with astrophysical neutrinos from IceCube

Author

Abe, S., Asami, S., Eizuka, M., Futagi, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Kinoshita, T., Koga, M., Kurasawa, M., Maemura, N., Mitsui, T., Miyake, H., Nakahata, T., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Smolsky, J., Lertprasertpong, J., Winslow, L. A., Fu, Z., Ouellet, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Song, H., O'Donnell, T., and Dell'Oro, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the results of a search for MeV-scale astrophysical neutrinos in KamLAND presented as an excess in the number of coincident neutrino interactions associated with the publicly available high-energy neutrino datasets from the IceCube Neutrino Observatory. We find no statistically significant excess in the number of observed low-energy electron antineutrinos in KamLAND, given a coincidence time window of $\pm$500s, $\pm$1,000s, $\pm$3,600s, and $\pm$10,000s around each of the IceCube neutrinos. We use this observation to present limits from 1.8 MeV to 100 MeV on the electron antineutrino fluence, assuming a mono-energetic flux. We then compare the results to several astrophysical measurements performed by IceCube and place a limit at the 90% confidence level on the electron antineutrino isotropic thermal luminosity from the TXS 0506+056 blazar., Comment: 12 pages, 5 figures

Published
2022
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28. Disseminated intravascular coagulation is associated with poor prognosis in patients with COVID-19

Author

Satoshi Gando and Takayuki Akiyama

Subjects
Coronavirus disease 2019 (COVID-19), Disseminated intravascular coagulation (DIC), Organ dysfunction, Incidence, Prognosis, Medicine, Science
Abstract

Abstract This study aimed to investigate the incidence and significance of disseminated intravascular coagulation (DIC) in coronavirus disease 2019 (COVID-19). A multicenter cohort study was conducted using large-scale COVID-19 registry data. The patients were classified into DIC and non-DIC groups based on the diagnosis on admission (day 1) and on any of the days 1, 4, 8, and 15. In total, 23,054 patients were divided into DIC (n = 264) and non-DIC (n = 22,790) groups on admission. Thereafter, 1654 patients were divided into 181 patients with DIC and 1473 non-DIC patients based on the DIC diagnosis on any of the days from 1 to 15. DIC incidence was 1.1% on admission, increasing to 10.9% by day 15. DIC diagnosis on admission had moderate predictive performance for developing multiple organ dysfunction syndrome (MODS) on day 4 and in-hospital death and was independently associated with MODS and in-hospital death. DIC diagnosis on any of the days from 1 to 15, especially days 8 and 15, was associated with lower survival probability than those without DIC and showed significant association with in-hospital death. In conclusion, despite its low incidence, DIC, particularly late-onset DIC, plays a significant role in the pathogenesis of poor prognosis in patients with COVID-19.

Published
2024
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29. A search for correlated low-energy electron antineutrinos in KamLAND with gamma-ray bursts

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Kinoshita, T., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Eizuka, M., Kurasawa, M., Nakahata, T., Futagi, S., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Yoshida, S., Umehara, S., Fushimi, K., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Smolsky, J., Laber-Smith, C., Winslow, L. A., Fu, Z., Ouellet, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Song, H., O'Donnell, T., and Dell'Oro, S.

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

We present the results of a time-coincident event search for low-energy electron antineutrinos in the KamLAND detector with gamma-ray bursts from the Gamma-ray Coordinates Network and Fermi Gamma-ray Burst Monitor. Using a variable coincidence time window of $\pm$500s plus the duration of each gamma-ray burst, no statistically significant excess above background is observed. We place the world's most stringent 90% confidence level upper limit on the electron antineutrino fluence below 17.5 MeV. Assuming a Fermi-Dirac neutrino energy spectrum from the gamma-ray burst source, we use the available redshift data to constrain the electron antineutrino luminosity and effective temperature., Comment: 9 pages, 3 figures

Published
2021
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30. Abundances of Uranium and Thorium Elements in Earth Estimated by Geoneutrino Spectroscopy

Author

Abe, S, Asami, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Koga, M, Kurasawa, M, Maemura, N, Mitsui, T, Miyake, H, Nakahata, T, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirahata, Y, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Yoshida, S, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Fu, Z, Smolsky, J, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Li, A, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, Song, H, O’Donnell, T, and Dell’Oro, S

Subjects
Affordable and Clean Energy, geoneutrino, radiogenic heat, Earth's interior, mantle composition, Meteorology & Atmospheric Sciences
Abstract

The decay of the primordial isotopes 238U, 235U, 232Th, and 40K has contributed to the terrestrial heat budget throughout the Earth's history. Hence, the individual abundance of those isotopes are key parameters in reconstructing contemporary Earth models. The geoneutrinos produced by the radioactive decays of uranium and thorium have been observed with the Kamioka Liquid-Scintillator Antineutrino Detector (KamLAND). Those measurements have been improved with more than 18-year observation time, and improvement in detector background levels mainly with an 8-year nearly reactor-free period, which now permit spectroscopy with geoneutrinos. Our results yield the first constraint on both uranium and thorium heat contributions. The KamLAND result is consistent with geochemical estimations based on elemental abundances of chondritic meteorites and mantle peridotites. The High-Q model is disfavored at 99.76% C.L. and a fully radiogenic model is excluded at 5.2σ assuming a homogeneous heat producing element distribution in the mantle.

Published
2022

31. Search for Supernova Neutrinos and Constraint on the Galactic Star Formation Rate with the KamLAND Data

Author

Abe, S, Asami, S, Eizuka, M, Futagi, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Koga, M, Kurasawa, M, Maemura, N, Mitsui, T, Miyake, H, Nakahata, T, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, A, Yoshida, S, Umehara, S, Fushimi, K, Kotera, K, Urano, Y, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Winslow, LA, Fu, Z, Smolsky, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Li, A, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, Song, H, O’Donnell, T, and Dell’Oro, S

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

We present the results of a search for core-collapse supernova neutrinos, using long-term KamLAND data from 2002 March 9 to 2020 April 25. We focus on the electron antineutrinos emitted from supernovae in the energy range of 1.8-111 MeV. Supernovae will make a neutrino event cluster with the duration of ∼10 s in the KamLAND data. We find no neutrino clusters and give the upper limit on the supernova rate to be 0.15 yr−1 with a 90% confidence level. The detectable range, which corresponds to a >95% detection probability, is 40-59 kpc and 65-81 kpc for core-collapse supernovae and failed core-collapse supernovae, respectively. This paper proposes to convert the supernova rate obtained by the neutrino observation to the Galactic star formation rate. Assuming a modified Salpeter-type initial mass function, the upper limit on the Galactic star formation rate is

Published
2022

33. Low-energy astrophysics with KamLAND

Author

Kawada, N, Obara, S, Ishidoshiro, K, Grant, C, O’Donnell, T, Dell’Oro, S, Abe, S, Asami, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hayashida, S, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Kamei, Y, Kishimoto, Y, Kinoshita, T, Koga, M, Maemura, N, Mitsui, T, Miyake, H, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Ueshima, K, Wada, Y, Watanabe, H, Yoshida, Y, Ichikawa, AK, Kozlov, A, Chernyak, D, Takemoto, Y, Yoshida, S, Umehara, S, Fushimi, K, Nakamura, KZ, Yoshida, M, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Winslow, LA, Fu, Z, Ouellet, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Li, A, Detwiler, JA, Enomoto, S, and Decowski, MP

Abstract

We present two results of a search for MeV-scale neutrino and anti-neutrino events correlated with gravitational wave events/candidates and large solar flares with KamLAND. The KamLAND detector is a large-volume neutrino detector using liquid scintillator, which is located at 1 km underground under the top of Mt. Ikenoyama in Kamioka, Japan. KamLAND has multiple reaction channels to detect neutrinos. Electron antineutrino can be detected via inverse-beta decay with 1.8 MeV neutrino energy threshold. All flavors of neutrinos can be detected via neutrino-electron scattering without neutrino energy threshold. KamLAND has continued the neutrino observation since 2002 March. We use the data set of 60 gravitational waves provided by the LIGO/Virgo collaboration during their second and third observing runs and search for coincident electron antineutrino events in KamLAND. We find no significant coincident signals within a ±500 s timing window from each gravitational wave and present 90% C.L. upper limits on the electron antineutrino fluence between 108–1013 cm−2 for neutrino energies of 1.8–111 MeV. For a solar-flare neutrino search at KamLAND, we determine the timing window using the solar X-ray data set provided by the GOES satellite series from 2002 to 2019 and search for the excess of coincident event rate on the all-flavor neutrinos. We find no significant event rate excess in the flare time windows and get 90% C.L. upper limits on the fluence of neutrinos of all flavors (electron anti-neutrinos) between 1010–1013 cm−2 (108–1013 cm−2) for neutrino energies in the energy range of 0.4–35 MeV.

Published
2022

34. A Search for Correlated Low-energy Electron Antineutrinos in KamLAND with Gamma-Ray Bursts

Author

Abe, S, Asami, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Kinoshita, T, Koga, M, Maemura, N, Mitsui, T, Miyake, H, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Eizuka, M, Kurasawa, M, Nakahata, T, Futagi, S, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Yoshida, S, Umehara, S, Fushimi, K, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Smolsky, J, Laber-Smith, C, Winslow, LA, Fu, Z, Ouellet, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Li, A, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, Song, H, O’Donnell, T, and Dell’Oro, S

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

We present the results of a time-coincident event search for low-energy electron antineutrinos in the KamLAND detector with gamma-ray bursts (GRBs) from the Gamma-ray Coordinates Network and Fermi Gamma-ray Burst Monitor. Using a variable coincidence time window of ±500 s plus the duration of each GRB, no statistically significant excess above the background is observed. We place the world's most stringent 90% confidence level upper limit on the electron antineutrino fluence below 17.5 MeV. Assuming a Fermi-Dirac neutrino energy spectrum from the GRB source, we use the available redshift data to constrain the electron antineutrino luminosity and effective temperature.

Published
2022

35. Limits on astrophysical antineutrinos with the KamLAND experiment

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kinoshita, T., Kishimoto, Y., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Ichikawa, A. K., Kozlov, A., Chernyak, D., Takemoto, Y., Yoshida, S., Umehara, S., Fushimi, K., Hirata, S., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. L., Learned, J. G., Maricic, J., Axani, S. N., Fu, Z., Ouellet, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., Dell'Oro, S., and O'donnell, T.

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

We report on a search for electron antineutrinos ($\bar{\nu}_e$) from astrophysical sources in the neutrino energy range 8.3 to 30.8 MeV with the KamLAND detector. In an exposure of 6.72 kton-year of the liquid scintillator, we observe 18 candidate events via the inverse beta decay reaction. Although there is a large background uncertainty from neutral current atmospheric neutrino interactions, we find no significant excess over background model predictions. Assuming several supernova relic neutrino spectra, we give upper flux limits of 60--110 cm$^{-2}$ s$^{-1}$ (90% CL) in the analysis range and present a model-independent flux. We also set limits on the annihilation rates for light dark matter pairs to neutrino pairs. These data improves on the upper probability limit of $^{8}$B solar neutrinos converting into $\bar{\nu}_e$'s, $P_{\nu_e \rightarrow \bar{\nu}_e} < 3.5\times10^{-5}$ (90% CL) assuming an undistorted $\bar{\nu}_e$ shape. This corresponds to a solar $\bar{\nu}_e$ flux of 60 cm$^{-2}$ s$^{-1}$ (90% CL) in the analysis energy range., Comment: 21 pages, 9 figures, 4 tables, accepted for publication in Astrophysical Journal

Published
2021
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38. Limits on Astrophysical Antineutrinos with the KamLAND Experiment

Author

Abe, S, Asami, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hayashida, S, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Kinoshita, T, Koga, M, Maemura, N, Mitsui, T, Miyake, H, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirahata, Y, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Ueshima, K, Wada, Y, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Kozlov, A, Chernyak, D, Takemoto, Y, Yoshida, S, Umehara, S, Fushimi, K, Hirata, S, Nakamura, KZ, Yoshida, M, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Winslow, LA, Fu, Z, Ouellet, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Li, A, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, O’Donnell, T, and Dell’Oro, S

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

We report on a search for electron antineutrinos ( ) from astrophysical sources in the neutrino energy range 8.3-30.8 MeV with the KamLAND detector. In an exposure of 6.72 kton-year of the liquid scintillator, we observe 18 candidate events via the inverse beta decay reaction. Although there is a large background uncertainty from neutral current atmospheric neutrino interactions, we find no significant excess over background model predictions. Assuming several supernova relic neutrino spectra, we give upper flux limits of 60-110 cm-2 s-1 (90% confidence level, CL) in the analysis range and present a model-independent flux. We also set limits on the annihilation rates for light dark matter pairs to neutrino pairs. These data improve on the upper probability limit of 8B solar neutrinos converting into , (90% CL) assuming an undistorted shape. This corresponds to a solar flux of 60 cm-2 s-1 (90% CL) in the analysis energy range.

Published
2022

39. Search for Solar Flare Neutrinos with the KamLAND Detector

Author

Abe, S, Asami, S, Gando, A, Gando, Y, Gima, T, Goto, A, Hachiya, T, Hata, K, Hayashida, S, Hosokawa, K, Ichimura, K, Ieki, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kawada, N, Kishimoto, Y, Kinoshita, T, Koga, M, Maemura, N, Mitsui, T, Miyake, H, Nakamura, K, Nakamura, R, Ozaki, H, Sakai, T, Sambonsugi, H, Shimizu, I, Shirai, J, Shiraishi, K, Suzuki, A, Suzuki, Y, Takeuchi, A, Tamae, K, Ueshima, K, Wada, Y, Watanabe, H, Yoshida, Y, Obara, S, Ichikawa, AK, Kozlov, A, Chernyak, D, Takemoto, Y, Yoshida, S, Umehara, S, Fushimi, K, Nakamura, KZ, Yoshida, M, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Axani, SN, Winslow, LA, Fu, Z, Ouellet, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Li, A, Detwiler, JA, Enomoto, S, Decowski, MP, Grant, C, O’Donnell, T, and Dell’Oro, S

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural), Astronomy & Astrophysics
Abstract

We report the result of a search for neutrinos in coincidence with solar flares from the GOES flare database. The search was performed on a 10.8 kton-year exposure of KamLAND collected from 2002 to 2019. This large exposure allows us to explore previously unconstrained parameter space for solar flare neutrinos. We found no statistical excess of neutrinos and established 90% confidence level upper limits of 8.4 × 107 cm-2 (3.0 × 109 cm-2) on the electron antineutrino (electron neutrino) fluence at 20 MeV normalized to the X12 flare, assuming that the neutrino fluence is proportional to the X-ray intensity.

Published
2022

40. Search for Solar Flare Neutrinos with the KamLAND detector

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Kinoshita, T., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Kozlov, A., Chernyak, D., Takemoto, Y., Yoshida, S., Umehara, S., Fushimi, K., Ichikawa, A. K., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S. N., Winslow, L. A., Fu, Z., Ouellet, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., O'Donnell, T., and Dell'Oro, S.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We report the result of a search for neutrinos in coincidence with solar flares from the GOES flare database. The search was performed on a 10.8 kton-year exposure of KamLAND collected from 2002 to 2019. This large exposure allows us to explore previously unconstrained parameter space for solar flare neutrinos. We found no statistical excess of neutrinos and established 90% confidence level upper limits of $8.4 \times 10^7$ cm$^{-2}$ ($3.0 \times 10^{9}$ cm$^{-2}$) on electron anti-neutrino (electron neutrino) fluence at 20 MeV normalized to the X12 flare, assuming that the neutrino fluence is proportional to the X-ray intensity., Comment: 13 pages, 9 figures, accepted October 27, 2021

Published
2021
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41. The nylon balloon for xenon loaded liquid scintillator in KamLAND-Zen 800 neutrinoless double-beta decay search experiment

Author

collaboration, KamLAND-Zen, Gando, Y., Gando, A., Hachiya, T., Hayashida, S., Hosokawa, K., Ikeda, H., Mitsui, T., Nakada, T., Obara, S., Ozaki, H., Shirai, J., Ueshima, K., Watanabe, H., Abe, S., Hata, K., Hayashi, A., Honda, Y., Ieki, S., Inoue, K., Ishidoshiro, K., Ishikawa, S., Kamei, Y., Kamizawa, K., Karino, Y., Kawada, N., Kinoshita, T., Koga, M., Matsuda, S., Miyake, H., Nakamura, K., Nemoto, K., Ono, A., Ota, N., Otsuka, S., Shibukawa, Y., Shimizu, I., Shirahata, Y., Soma, K., Suzuki, A., Suzuki, A. A., Takai, T., Takeuchi, A., Tamae, K., Teraoka, Y., Wada, Y., Chernyak, D., Kozlov, A., Yoshida, S., Umehara, S., Takemoto, Y., Fushimi, K., Hirata, S., Grant, C., Li, A., Learned, J. G., Maricic, J., Berger, B. E., Fujikawa, B. K., Fraker, S., Herman, A., Krupczak, E., Pease, G. L., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., O'Donnell, T., Dell'Oro, S., Detwiler, J. A., Enomoto, S., and Decowski, M. P.

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

The KamLAND-Zen 800 experiment is searching for the neutrinoless double-beta decay of $^{136}$Xe by using $^{136}$Xe-loaded liquid scintillator. The liquid scintillator is enclosed inside a balloon made of thin, transparent, low-radioactivity film that we call Inner Balloon (IB). The IB, apart from guaranteeing the liquid containment, also allows to minimize the background from cosmogenic muon-spallation products and $^{8}$B solar neutrinos. Indeed these events could contribute to the total counts in the region of interest around the Q-value of the double-beta decay of $^{136}$Xe. In this paper, we present an overview of the IB and describe the various steps of its commissioning minimizing the radioactive contaminations, from the material selection, to the fabrication of the balloon and its installation inside the KamLAND detector. Finally, we show the impact of the IB on the KamLAND background as measured by the KamLAND detector itself., Comment: 23 pages, 16 figures, to be submitted to JINST

Published
2021
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42. A Search for Charged Excitation of Dark Matter with the KamLAND-Zen Detector

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kinoshita, T., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ono, A., Ota, N., Otsuka, S., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirahata, Y., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Chernyak, D., Kozlov, A., Yoshida, S., Umehara, S., Takemoto, Y., Fushimi, K., Hirata, S., Ichikawa, A., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. K., Grant, C., Li, A., Learned, J. G., Maricic, J., Axani, S., Winslow, L. A., Fu, Z., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., ODonnell, T., DellOro, S., Detwiler, J. A., Enomoto, S., and Decowski, M. P.

Subjects
High Energy Physics - Experiment
Abstract

There are many theories where a dark matter particle is part of a multiplet with an electrically charged state. If WIMP dark matter ($\chi^{0}$) is accompanied by a charged excited state ($\chi^{-}$) separated by a small mass difference, it can form a stable bound state with a nucleus. In supersymmetric models, the $\chi^{0}$ and the $\chi^{-}$ could be the neutralino and a charged slepton, such as the neutralino-stau degenerate model. The formation binding process is expected to result in an energy deposition of {\it O}(1--10 MeV), making it suitable for detection in large liquid scintillator detectors. We describe new constraints on the bound state formation with a xenon nucleus using the KamLAND-Zen 400 Phase-II dataset. In order to enlarge the searchable parameter space, all xenon isotopes in the detector were used. For a benchmark parameter set of $m_{\chi^{0}} = 100$ GeV and $\Delta m = 10$ MeV, this study sets the most stringent upper limits on the recombination cross section $\langle\sigma v\rangle$ and the decay-width of $\chi^{-}$ of $2.0 \times 10^{-31}$ ${\rm cm^3/s}$ and $1.1 \times 10^{-18}$ GeV, respectively (90\% confidence level).

Published
2021

44. Search for Low-energy Electron Antineutrinos in KamLAND Associated with Gravitational Wave Events

Author

Abe, S., Asami, S., Gando, A., Gando, Y., Gima, T., Goto, A., Hachiya, T., Hata, K., Hayashida, S., Hosokawa, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Kinoshita, T., Koga, M., Maemura, N., Mitsui, T., Miyake, H., Nakamura, K., Nakamura, R., Ozaki, H., Sakai, T., Sambonsugi, H., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Suzuki, Y., Takeuchi, A., Tamae, K., Ueshima, K., Wada, Y., Watanabe, H., Yoshida, Y., Obara, S., Kozlov, A., Chernyak, D., Takemoto, Y., Yoshida, S., Umehara, S., Fushimi, K., Ichikawa, A. K., Nakamura, K. Z., Yoshida, M., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Axani, S., Winslow, L. A., Fu, Z., Ouellet, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Li, A., Detwiler, J. A., Enomoto, S., Decowski, M. P., Grant, C., O'Donnell, T., and Dell'Oro, S.

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

We present the results of a search for MeV-scale electron antineutrino events in KamLAND in coincident with the 60 gravitational wave events/candidates reported by the LIGO/Virgo collaboration during their second and third observing runs. We find no significant coincident signals within a $\pm$ 500 s timing window from each gravitational wave and present 90% C.L. upper limits on the electron antineutrino fluence between $10^{8}$-$10^{13}\,{\mathrm cm^2}$ for neutrino energies in the energy range of 1.8-111 MeV., Comment: 11 pages, 2 figures, 2 tables, Accepted for publication in ApJ

Published
2020
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48. The nylon balloon for xenon loaded liquid scintillator in KamLAND-Zen 800 neutrinoless double-beta decay search experiment

Author

Gando, Y, Gando, A, Hachiya, T, Hayashida, S, Hosokawa, K, Ikeda, H, Mitsui, T, Nakada, T, Obara, S, Ozaki, H, Shirai, J, Ueshima, K, Watanabe, H, Abe, S, Hata, K, Hayashi, A, Honda, Y, Ieki, S, Inoue, K, Ishidoshiro, K, Ishikawa, S, Kamei, Y, Kamizawa, K, Karino, Y, Kawada, N, Kinoshita, T, Koga, M, Matsuda, S, Miyake, H, Nakamura, K, Nemoto, K, Ono, A, Ota, N, Otsuka, S, Shibukawa, Y, Shimizu, I, Shirahata, Y, Soma, K, Suzuki, A, Suzuki, AA, Takai, T, Takeuchi, A, Tamae, K, Teraoka, Y, Wada, Y, Chernyak, D, Kozlov, A, Yoshida, S, Umehara, S, Takemoto, Y, Fushimi, K, Hirata, S, Grant, C, Li, A, Learned, JG, Maricic, J, Berger, BE, Fujikawa, BK, Fraker, S, Herman, A, Krupczak, E, Pease, GL, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, O'Donnell, T, Dell'Oro, S, Detwiler, JA, Enomoto, S, and Decowski, MP

Subjects
Double-beta decay detectors, Large detector systems for particle and astroparticle physics, Liquid detectors, Physical Sciences, Engineering, Nuclear & Particles Physics
Abstract

The KamLAND-Zen 800 experiment is searching for the neutrinoless double-beta decay of 136Xe by using 136Xe-loaded liquid scintillator. The liquid scintillator is enclosed inside a balloon made of thin, transparent, low-radioactivity film that we call Inner Balloon (IB). The IB, apart from guaranteeing the liquid containment, also allows to minimize the background from cosmogenic muon-spallation products and 8B solar neutrinos. Indeed these events could contribute to the total counts in the region of interest around the Q-value of the double-beta decay of 136Xe. In this paper, we present an overview of the IB and describe the various steps of its commissioning minimizing the radioactive contaminations, from the material selection, to the fabrication of the balloon and its installation inside the KamLAND detector. Finally, we show the impact of the IB on the KamLAND background as measured by the KamLAND detector itself.

Published
2021

49. Risk factors for multidrug-resistant tuberculosis in the Central African Republic: A case-control study

Author

Jean de Dieu Longo, Sylvain Honoré Woromogo, Gaspard Tekpa, Henri Saint-Calvaire Diemer, Hervé Gando, Fernand Armel Djidéré, and Gérard Grésenguet

Subjects
Tuberculosis, Multidrug-resistant tuberculosis, Risk factors, Bangui, Infectious and parasitic diseases, RC109-216, Public aspects of medicine, RA1-1270
Abstract

Background: The emergence and spread of multidrug-resistant tuberculosis (MDR-TB) presents a challenge to the ''End TB by 2035'' strategy. This study aimed to identify the risk factors associated with MDR-TB in patients admitted to the pneumo-physiology clinic of the National University Hospital of Bangui in Central African Republic. Methods: This was a “retrospective” chart review study. Cases were represented by patients more than 18 years of age treated for MDR-TB and controls were patients with “at least rifampicin-susceptible” TB treated ''with first-line anti-TB regimen'' and who at the end of treatment were declared cured. The status of “cured” was exclusively applicable to non-MDR TB. Risk factors associated with MDR-TB were identified by multivariate analysis. Results: We included 70 cases and 140 controls. The median age was 35 years, IQR (22;46 years). The main factors associated with the occurrence of MDR-TB in multivariate analysis were male gender (0 R = 3.02 [1.89–3.99], p = 0.001), residence in a peri-urban/urban area (0 R = 3.06 [2.21–4.01], p = 0.002), history of previous TB treatment (0 R= 3.99 [2.77–4.25], p

Published
2023
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