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480 results on '"Shimizu I"'

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. 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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6. 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

7. 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

8. 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

9. 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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10. 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

11. 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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12. 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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13. 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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14. KamNet: An Integrated Spatiotemporal Deep Neural Network for Rare Event Search in KamLAND-Zen

Author

Li, A., Fu, Z., Winslow, L., Grant, C., Song, H., Ozaki, H., Shimizu, I., and Takeuchi, A.

Subjects
Physics - Instrumentation and Detectors, Computer Science - Machine Learning
Abstract

Rare event searches allow us to search for new physics at energy scales inaccessible with other means by leveraging specialized large-mass detectors. Machine learning provides a new tool to maximize the information provided by these detectors. The information is sparse, which forces these algorithms to start from the lowest level data and exploit all symmetries in the detector to produce results. In this work we present KamNet which harnesses breakthroughs in geometric deep learning and spatiotemporal data analysis to maximize the physics reach of KamLAND-Zen, a kiloton scale spherical liquid scintillator detector searching for neutrinoless double beta decay ($0\nu\beta\beta$). Using a simplified background model for KamLAND we show that KamNet outperforms a conventional CNN on benchmarking MC simulations with an increasing level of robustness. Using simulated data, we then demonstrate KamNet's ability to increase KamLAND-Zen's sensitivity to $0\nu\beta\beta$ and $0\nu\beta\beta$ to excited states. A key component of this work is the addition of an attention mechanism to elucidate the underlying physics KamNet is using for the background rejection., Comment: 12 pages, dual submission with upcoming KamLAND-Zen 800 main result

Published
2022
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15. 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

16. 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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17. 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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18. 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

19. 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

20. 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

21. 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

22. 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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23. 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

24. 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

25. 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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26. 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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27. 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

28. Supernova Model Discrimination with Hyper-Kamiokande

Author

Collaboration, Hyper-Kamiokande, Abe, K., Adrich, P., Aihara, H., Akutsu, R., Alekseev, I., Ali, A., Ameli, F., Anghel, I., Anthony, L. H. V., Antonova, M., Araya, A., Asaoka, Y., Ashida, Y., Aushev, V., Ballester, F., Bandac, I., Barbi, M., Barker, G. J., Barr, G., Batkiewicz-Kwasniak, M., Bellato, M., Berardi, V., Bergevin, M., Bernard, L., Bernardini, E., Berns, L., Bhadra, S., Bian, J., Blanchet, A., Blaszczyk, F. d. M., Blondel, A., Boiano, A., Bolognesi, S., Bonavera, L., Booth, N., Borjabad, S., Boschi, T., Bose, D., Boyd, S . B., Bozza, C., Bravar, A., Bravo-Berguño, D., Bronner, C., Brown, L., Bubak, A., Buchowicz, A., Avanzini, M. Buizza, Cafagna, F. S., Calabria, N. F., Calvo-Mozota, J. M., Cao, S., Cartwright, S. L., Carroll, A., Catanesi, M. G., Cebriàn, S., Chabera, M., Chakraborty, S., Checchia, C., Choi, J. H., Choubey, S., Cicerchia, M., Coleman, J., Collazuol, G., Cook, L., Cowan, G., Cuen-Rochin, S., Danilov, M., Lopez, G. Daz, De la Fuente, E., de Perio, P., De Rosa, G., Dealtry, T., Densham, C. J., Dergacheva, A., Deshmukh, N., Devi, M. M., Di Lodovico, F., Di Meo, P., Di Palma, I., Doyle, T. A., Drakopoulou, E., Drapier, O., Dumarchez, J., Dunne, P., Dziewiecki, M., Eklund, L., Hedri, S. El, Ellis, J., Emery, S., Esmaili, A., Esteve, R., Evangelisti, A., Feely, M., Fedotov, S., Feng, J., Fernandez, P., Fernández-Martinez, E., Ferrario, P., Ferrazzi, B., Feusels, T., Finch, A., Finley, C., Fiorentini, A., Fiorillo, G., Fitton, M., Frankiewicz, K., Friend, M., Fujii, Y., Fukuda, Y., Galinski, G., Gao, J., Garde, C., Garfagnini, A., Garode, S., Gialanella, L., Giganti, C., Gomez-Cadenas, J. J., Gonin, M., González-Nuevo, J., Gorin, A., Gornea, R., Gousy-Leblanc, V., Gramegna, F., Grassi, M., Grella, G., Guigue, M., Gumplinger, P., Hadley, D. R., Harada, M., Hartfiel, B., Hartz, M., Hassani, S., Hastings, N. C., Hayato, Y., Hernando-Morata, J. A., Herrero, V., Hill, J., Hiraide, K., Hirota, S., Holin, A., Horiuchi, S., Hoshina, K., Hultqvist, K., Iacob, F., Ichikawa, A. K., Ibnsalih, W. Idrissi, Iijima, T., Ikeda, M., Inomoto, M., Inoue, K., Insler, J., Ioannisian, A., Ishida, T., Ishidoshiro, K., Ishino, H., Ishitsuka, M., Ito, H., Ito, S., Itow, Y., Iwamoto, K., Izmaylov, A., Izumi, N., Izumiyama, S., Jakkapu, M., Jamieson, B., Jang, H. I., Jang, J. S., Jenkins, S. J., Jeon, S. H., Jiang, M., Jo, H. S., Jonsson, P., Joo, K. K., Kajita, T., Kakuno, H., Kameda, J., Kano, Y., Kalaczynski, P., Karlen, D., Kasperek, J., Kataoka, Y., Kato, A., Katori, T., Kazarian, N., Kearns, E., Khabibullin, M., Khotjantsev, A., Kikawa, T., Kikec, M., Kim, J. H., Kim, J. Y., Kim, S. B., Kim, S. Y., King, S., Kinoshita, T., Kisiel, J., Klekotko, A., Kobayashi, T., Koch, L., Koga, M., Koerich, L., Kolev, N., Konaka, A., Kormos, L. L., Koshio, Y., Korzenev, A., Kotsar, Y., Kouzakov, K. A., Kowalik, K. L., Kravchuk, L., Kryukov, A. P., Kudenko, Y., Kumita, T., Kurjata, R., Kutter, T., Kuze, M., Kwak, K., La Commara, M., Labarga, L., Lagoda, J., James, M. Lamers, Lamoureux, M., Laveder, M., Lavitola, L., Lawe, M., Learned, J. G., Lee, J., Leitner, R., Lezaun, V., Lim, I. T., Lindner, T., Litchfield, R. P., Long, K. R., Longhin, A., Loverre, P., Lu, X., Ludovici, L., Maekawa, Y., Magaletti, L., Magar, K., Mahn, K., Makida, Y., Malek, M., Malinský, M., Marchi, T., Maret, L., Mariani, C., Marinelli, A., Martens, K., Marti, Ll., Martin, J. F., Martin, D., Marzec, J., Matsubara, T., Matsumoto, R., Matsuno, S., Matusiak, M., Mazzucato, E., McCarthy, M., McCauley, N., McElwee, J., McGrew, C., Mefodiev, A., Medhi, A., Mehta, P., Mellet, L., Menjo, H., Mermod, P., Metelko, C., Mezzetto, M., Migenda, J., Migliozzi, P., Mijakowski, P., Miki, S., Miller, E. W., Minakata, H., Minamino, A., Mine, S., Mineev, O., Mitra, A., Miura, M., Moharana, R., Mollo, C. M., Mondal, T., Mongelli, M., Monrabal, F., Moon, D. H., Moon, C. S., Mora, F. J., Moriyama, S., Mueller, Th. A., Munteanu, L., Murase, K., Nagao, Y., Nakadaira, T., Nakagiri, K., Nakahata, M., Nakai, S., Nakajima, Y., Nakamura, K., Nakamura, KI., Nakamura, H., Nakano, Y., Nakaya, T., Nakayama, S., Nakayoshi, K., Machado, L. Nascimento, Naseby, C. E. R., Navarro-Garcia, B., Needham, M., Nicholls, T., Niewczas, K., Nishimura, Y., Noah, E., Nova, F., Nugent, J. C., Nunokawa, H., Obrebski, W., Ochoa-Ricoux, J. P., O'Connor, E., Ogawa, N., Ogitsu, T., Ohta, K., Okamoto, K., O'Keeffe, H. M., Okumura, K., Onishchuk, Y., Orozco-Luna, F., Oshlianskyi, A., Ospina, N., Ostrowski, M., O'Sullivan, E., O'Sullivan, L., Ovsiannikova, T., Oyama, Y., Ozaki, H., Pac, M. Y., Paganini, P., Palladino, V., Paolone, V., Pari, M., Parsa, S., Pasternak, J., Pastore, C., Pastuszak, G., Patel, D. A., Pavin, M., Payne, D., Peña-Garay, C., Pidcott, C., Guerra, E. Pinzon, Playfer, S., Pointon, B. W., Popov, A., Popov, B., Porwit, K., Posiadala-Zezula, M., Poutissou, J. -M., Pozimski, J., Pronost, G., Prouse, N. W., Przewlocki, P., Quilain, B., Quiroga, A. A., Radicioni, E., Radics, B., Rajda, P. J., Renner, J., Rescigno, M., Retiere, F., Ricciardi, G., Riccio, C., Richards, B., Rondio, E., Rose, H. J., Roskovec, B., Roth, S., Rott, C., Rountree, S. D., Rubbia, A., Ruggeri, A. C., Ruggles, C., Russo, S., Rychter, A., Ryu, D., Sakashita, K., Samani, S., Sánchez, F., Sánchez, M. L., Sanchez, M. C., Sano, S., Santos, J. D., Santucci, G., Sarmah, P., Sashima, I., Sato, K., Scott, M., Seiya, Y., Sekiguchi, T., Sekiya, H., Seo, J. W., Seo, S. H., Sgalaberna, D., Shaikhiev, A., Shan, Z., Shaykina, A., Shimizu, I., Shin, C. D., Shinoki, M., Shiozawa, M., Sinnis, G., Skrobova, N., Skwarczynski, K., Smy, M. B., Sobczyk, J., Sobel, H. W., Soler, F. J. P., Sonoda, Y., Spina, R., Spisso, B., Spradlin, P., Stankevich, K. L., Stawarz, L., Stellacci, S. M., Stopa, K., Studenikin, A. I., Gómez, S. L. Suárez, Suganuma, T., Suvorov, S., Suwa, Y., Suzuki, A. T., Suzuki, S. Y., Suzuki, Y., Svirida, D., Svoboda, R., Taani, M., Tada, M., Takeda, A., Takemoto, Y., Takenaka, A., Taketa, A., Takeuchi, Y., Takhistov, V., Tanaka, H., Tanaka, H. A., Tanaka, H. I., Tanaka, M., Tashiro, T., Thiesse, M., Thompson, L. F., Toledo, J., Tomatani-Sánchez, A. K., Tortone, G., Tsui, K. M., Tsukamoto, T., Tzanov, M., Uchida, Y., Vagins, M. R., Valder, S., Valentino, V., Vasseur, G., Vijayvargi, A., Vilela, C., Vinning, W. G. S., Vivolo, D., Vladisavljevic, T., Vogelaar, R. B., Vyalkov, M. M., Wachala, T., Walker, J., Wark, D., Wascko, M. O., Wendell, R. A., Wilkes, R. J., Wilking, M. J., Wilson, J. R., Wronka, S., Xia, J., Xie, Z., Xin, T., Yamaguchi, Y., Yamamoto, K., Yanagisawa, C., Yano, T., Yen, S., Yershov, N., Yeum, D. N., Yokoyama, M., Yonenaga, M., Yoo, J., Yu, I., Yu, M., Zakrzewski, T., Zaldivar, B., Zalipska, J., Zaremba, K., Zarnecki, G., Ziembicki, M., Zietara, K., Zito, M., and Zsoldos, S.

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

Core-collapse supernovae are among the most magnificent events in the observable universe. They produce many of the chemical elements necessary for life to exist and their remnants -- neutron stars and black holes -- are interesting astrophysical objects in their own right. However, despite millennia of observations and almost a century of astrophysical study, the explosion mechanism of core-collapse supernovae is not yet well understood. Hyper-Kamiokande is a next-generation neutrino detector that will be able to observe the neutrino flux from the next galactic core-collapse supernova in unprecedented detail. We focus on the first 500 ms of the neutrino burst, corresponding to the accretion phase, and use a newly-developed, high-precision supernova event generator to simulate Hyper-Kamiokande's response to five different supernova models. We show that Hyper-Kamiokande will be able to distinguish between these models with high accuracy for a supernova at a distance of up to 100 kpc. Once the next galactic supernova happens, this ability will be a powerful tool for guiding simulations towards a precise reproduction of the explosion mechanism observed in nature., Comment: 21 pages, 7 figures. Article based on thesis published as arXiv:2002.01649. v2: added references and some explanations in response to reviewer comments

Published
2021
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29. 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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30. A puzzling non-detection of [O III] and [C II] from a $z \approx 7.7$ galaxy observed with ALMA

Author

Binggeli, C., Inoue, A. K., Hashimoto, T., Toribio, M. C., Zackrisson, E., Ramstedt, S., Mawatari, K., Harikane, Y., Matsuo, H., Okamoto, T., Ota, K., Shimizu, I., Tamura, Y., Taniguchi, Y., and Umehata, H.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Characterizing the galaxy population in the early Universe holds the key to understanding the evolution of these objects and the role they played in cosmic reionization. However, the number of observations at the very highest redshifts are to date, few. In order to shed light on the properties of galaxies in the high-redshift Universe and their interstellar media, we observe the Lyman-$\alpha$ emitting galaxy z7\_GSD\_3811 at $z=7.664$ with band 6 and 8 at the Atacama Large Millimeter/submillimeter Array (ALMA). We target the far-infrared [O III] 88 $\mu m$, [C II] 158 $\mu m$ emission lines and dust continuum in the star-forming galaxy z7\_GSD\_3811 with ALMA. We combine these measurements with earlier observations in the rest-frame ultraviolet (UV) in order to characterize the object, and compare results to those of earlier studies observing [O III] and [C II] emission in high-redshift galaxies. The [O III] 88 $\mu m$ and [C II] 158 $\mu m$ emission lines are undetected at the position of z7\_GSD\_3811, with $3\sigma$ upper limits of $1.6 \ \times \ 10^{8} \ L_{\odot}$ and $4.0 \ \times \ 10^{7} \ L_{\odot}$, respectively. We do not detect any dust continuum in band 6 nor band 8. The measured rms in the band 8 and band 6 continuum is 26 and 9.9 $\mu Jy \ beam^{-1}$, respectively. Similar to several other high-redshift galaxies, z7\_GSD\_3811 exhibits low [C II] emission for its star formation rate compared to local galaxies. Furthermore, our upper limit on the [O III] line luminosity is lower than all the previously observed [O III] lines in high-redshift galaxies with similar ultraviolet luminosities. Our ALMA band 6 and 8 dust continuum observations imply that z7\_GSD\_3811 likely has a low dust content, and our non-detections of the [O III] and [C II] lines could indicate that z7\_GSD\_3811 has a low metallicity ($Z \lesssim 0.1 \ Z_{\odot}$)., Comment: 13 pages, 7 figures, accepted for publication in Astronomy and Astrophysics

Published
2020
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31. The Hyper-Kamiokande Experiment -- Snowmass LOI

Author

Collaboration, Hyper-Kamiokande, Abe, K., Adrich, P., Aihara, H., Akutsu, R., Alekseev, I., Ali, A., Ameli, F., Anthony, L. H. V., Araya, A., Asaoka, Y., Aushev, V., Bandac, I., Barbi, M., Barr, G., Batkiewicz-Kwasniak, M., Bellato, M., Berardi, V., Bernard, L., Bernardini, E., Berns, L., Bhadra, S., Bian, J., Blanchet, A., Blondel, A., Boiano, A., Bolognesi, S., Bonavera, L., Borjabad, S., Boschi, T., Bose, D., Boyd, S . B., Bozza, C., Bravar, A., Bronner, C., Bubak, A., Buchowicz, A., Avanzini, M. Buizza, Cafagna, F. S., Calabria, N. F., Calvo-Mozota, J. M., Cao, S., Catanesi, M. G., Chakraborty, S., Choi, J. H., Choubey, S., Cicerchia, M., Coleman, J., Collazuol, G., Cuen-Rochin, S., Danilov, M., De la Fuente, E., de Perio, P., De Rosa, G., Dealtry, T., Densham, C. J., Dergacheva, A., Deshmukh, N., Devi, M. M., Di Lodovico, F., Di Meo, P., Di Palma, I., Doyle, T. A., Drakopoulou, E., Drapier, O., Dumarchez, J., Eklund, L., Hedri, S. El, Ellis, J., Emery, S., Esmaili, A., Fedotov, S., Feng, J., Fernández-Martinez, E., Ferrario, P., Ferrazzi, B., Finch, A., Finley, C., Fiorillo, G., Fitton, M., Friend, M., Fujii, Y., Fukuda, Y., Galinski, G., Gao, J., Garde, C., Garfagnini, A., Garode, S., Gialanella, L., Giganti, C., Gomez-Cadenas, J. J., Gonin, M., González-Nuevo, J., Gorin, A., Gornea, R., Gramegna, F., Grassi, M., Grella, G., Guigue, M., Hadley, D. R., Harada, M., Hartz, M., Hassani, S., Hastings, N. C., Hayato, Y., Hiraide, K., Hoshina, K., Hultqvist, K., Iacob, F., Ichikawa, A. K., Ibnsalih, W. Idrissi, Ikeda, M., Inomoto, M., Ioannisian, A., Ishida, T., Ishidoshiro, K., Ishino, H., Ishitsuka, M., Ito, H., Ito, S., Itow, Y., Iwamoto, K., Izumi, N., Izumiyama, S., Jakkapu, M., Jamieson, B., Jang, J. S., Jo, H. S., Jonsson, P., Joo, K. K., Kajita, T., Kakuno, H., Kameda, J., Kano, Y., Karlen, D., Kataoka, Y., Kato, A., Katori, T., Kazarian, N., Khabibullin, M., Khotjantsev, A., Kikawa, T., Kim, J. Y., Kim, S. B., King, S., Kinoshita, T., Kisiel, J., Klekotko, A., Kobayashi, T., Koerich, L., Kolev, N., Konaka, A., Kormos, L. L., Koshio, Y., Kotsar, Y., Kouzakov, K. A., Kowalik, K. L., Kravchuk, L., Kryukov, A. P., Kudenko, Y., Kumita, T., Kurjata, R., Kutter, T., Kuze, M., Kwak, K., La Commara, M., Labarga, L., Lagoda, J., Lamoureux, M., Laveder, M., Lavitola, L., Lee, J., Leitner, R., Lezaun, V., Lim, I. T., Lindner, T., Litchfield, R. P., Long, K. R., Longhin, A., Loverre, P., Lu, X., Ludovici, L., Maekawa, Y., Magaletti, L., Magar, K., Makida, Y., Malek, M., Malinský, M., Marchi, T., Mariani, C., Marinelli, A., Martens, K., Marti, Ll., Martin, J. F., Martin, D., Marzec, J., Matsubara, T., Matsumoto, R., McCauley, N., Medhi, A., Mehta, P., Mellet, L., Menjo, H., Mezzetto, M., Migenda, J., Migliozzi, P., Miki, S., Minamino, A., Mine, S., Mineev, O., Mitra, A., Miura, M., Moharana, R., Mollo, C. M., Mondal, T., Mongelli, M., Monrabal, F., Moon, D. H., Moon, C. S., Moriyama, S., Mueller, T., Nagao, Y., Nakadaira, T., Nakagiri, K., Nakahata, M., Nakai, S., Nakajima, Y., Nakamura, K., Nakamura, KI., Nakamura, H., Nakano, Y., Nakaya, T., Nakayama, S., Nakayoshi, K., Machado, L. Nascimento, Naseby, C. E. R., Navarro-Garcia, B., Needham, M., Niewczas, K., Nishimura, Y., Nova, F., Nugent, J. C., Nunokawa, H., Obrebski, W., Ochoa-Ricoux, J. P., O'Connor, E., Ogawa, N., Ogitsu, T., Okamoto, K., O'Keeffe, H. M., Okumura, K., Onishchuk, Y., Orozco-Luna, F., Oshlianskyi, A., Ospina, N., Ostrowski, M., O'Sullivan, E., Oyama, Y., Ozaki, H., Pac, M. Y., Paganini, P., Palladino, V., Pari, M., Pasternak, J., Pastore, C., Pastuszak, G., Patel, D. A., Pavin, M., Payne, D., Peña-Garay, C., Pidcott, C., Playfer, S., Pointon, B. W., Popov, A., Popov, B., Porwit, K., Posiadala-Zezula, M., Pronost, G., Prouse, N. W., Quilain, B., Quiroga, A. A., Radicioni, E., Radics, B., Rajda, P. J., Rescigno, M., Ricciardi, G., Richards, B., Rondio, E., Roskovec, B., Roth, S., Rott, C., Rubbia, A., Ruggeri, A. C., Russo, S., Rychter, A., Ryu, D., Sakashita, K., Samani, S., Sánchez, F., Sánchez, M. L., Sano, S., Santos, J. D., Santucci, G., Sarmah, P., Sato, K., Scott, M., Seiya, Y., Sekiguchi, T., Sekiya, H., Seo, J. W., Sgalaberna, D., Shaykina, A., Shimizu, I., Shin, C. D., Shinoki, M., Shiozawa, M., Skrobova, N., Skwarczynski, K., Smy, M. B., Sobczyk, J., Sobel, H. W., Soler, F. J. P., Sonoda, Y., Spina, R., Spisso, B., Spradlin, P., Stankevich, K. L., Stawarz, L., Stellacci, S. M., Studenikin, A. I., Gómez, S. L. Suárez, Suganuma, T., Suvorov, S., Suwa, Y., Suzuki, A. T., Suzuki, S., Suzuki, Y., Svirida, D., Taani, M., Tada, M., Takeda, A., Takemoto, Y., Takenaka, A., Taketa, A., Takeuchi, Y., Tanaka, H., Tanaka, H. I., Tanaka, M., Tashiro, T., Thiesse, M., Thompson, L. F., Tomatani-Sánchez, A. K., Tortone, G., Tsui, K. M., Tsukamoto, T., Tzanov, M., Uchida, Y., Vagins, M. R., Valder, S., Valentino, V., Vasseur, G., Vijayvargi, A., Vinning, W. G. S., Vivolo, D., Vogelaar, R. B., Vyalkov, M. M., Wachala, T., Walker, J., Wark, D., Wascko, M. O., Wendell, R. A., Wilson, J. R., Wronka, S., Xia, J., Yamaguchi, Y., Yamamoto, K., Yano, T., Yershov, N., Yokoyama, M., Yoo, J., Yu, I., Zakrzewski, T., Zaldivar, B., Zalipska, J., Zaremba, K., Zarnecki, G., Ziembicki, M., Zietara, K., Zito, M., and Zsoldos, S.

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

Hyper-Kamiokande is the next generation underground water Cherenkov detector that builds on the highly successful Super-Kamiokande experiment. The detector which has an 8.4~times larger effective volume than its predecessor will be located along the T2K neutrino beamline and utilize an upgraded J-PARC beam with 2.6~times beam power. Hyper-K's low energy threshold combined with the very large fiducial volume make the detector unique, that is expected to acquire an unprecedented exposure of 3.8~Mton$\cdot$year over a period of 20~years of operation. Hyper-Kamiokande combines an extremely diverse science program including nucleon decays, long-baseline neutrino oscillations, atmospheric neutrinos, and neutrinos from astrophysical origins. The scientific scope of this program is highly complementary to liquid-argon detectors for example in sensitivity to nucleon decay channels or supernova detection modes. Hyper-Kamiokande construction has started in early 2020 and the experiment is expected to start operations in 2027. The Hyper-Kamiokande collaboration is presently being formed amongst groups from 19 countries including the United States, whose community has a long history of making significant contributions to the neutrino physics program in Japan. US physicists have played leading roles in the Kamiokande, Super-Kamiokande, EGADS, K2K, and T2K programs., Comment: 6 pages, prepared as Snowmass2021 LOI

Published
2020

32. 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

33. 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, AK, 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
astro-ph.SR, 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

We report the result of a search for neutrinos in coincidence with solarflares from the GOES flare database. The search was performed on a 10.8kton-year exposure of KamLAND collected from 2002 to 2019. This large exposureallows us to explore previously unconstrained parameter space for solar flareneutrinos. We found no statistical excess of neutrinos and established 90%confidence level upper limits of $8.4 \times 10^7$ cm$^{-2}$ ($3.0 \times10^{9}$ cm$^{-2}$) on electron anti-neutrino (electron neutrino) fluence at 20MeV normalized to the X12 flare, assuming that the neutrino fluence isproportional to the X-ray intensity.

Published
2021

34. 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, AK, 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
Neutrino astronomy, Gravitational waves, astro-ph.HE, hep-ex, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry, Astronomy & Astrophysics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural)
Abstract

We present the results of a search for MeV-scale electron antineutrino events in KamLAND 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 500 s timing window from each gravitational wave and present 90% C.L. upper limits on the electron antineutrino fluence between 108 and 1013 cm-2 for neutrino energies in the energy range of 1.8-111 MeV.

Published
2021

35. 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, KZ, Yoshida, M, Berger, BE, Fujikawa, BK, Grant, C, Li, A, Learned, JG, Maricic, J, Axani, S, Winslow, LA, Fu, Z, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, ODonnell, T, DellOro, S, Detwiler, JA, Enomoto, S, and Decowski, MP

Subjects
hep-ex
Abstract

There are many theories where a dark matter particle is part of a multipletwith an electrically charged state. If WIMP dark matter ($\chi^{0}$) isaccompanied by a charged excited state ($\chi^{-}$) separated by a small massdifference, it can form a stable bound state with a nucleus. In supersymmetricmodels, the $\chi^{0}$ and the $\chi^{-}$ could be the neutralino and a chargedslepton, such as the neutralino-stau degenerate model. The formation bindingprocess is expected to result in an energy deposition of {\it O}(1--10 MeV),making it suitable for detection in large liquid scintillator detectors. Wedescribe new constraints on the bound state formation with a xenon nucleususing the KamLAND-Zen 400 Phase-II dataset. In order to enlarge the searchableparameter space, all xenon isotopes in the detector were used. For a benchmarkparameter set of $m_{\chi^{0}} = 100$ GeV and $\Delta m = 10$ MeV, this studysets the most stringent upper limits on the recombination cross section$\langle\sigma v\rangle$ and the decay-width of $\chi^{-}$ of $2.0 \times10^{-31}$ ${\rm cm^3/s}$ and $1.1 \times 10^{-18}$ GeV, respectively (90\%confidence level).

Published
2021

36. Balmer breaks in simulated galaxies at z>6

Author

Binggeli, C., Zackrisson, E., Ma, X., Inoue, A. K., Vikaeus, A., Hashimoto, T., Mawatari, K., Shimizu, I., and Ceverino, D.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Photometric observations of the spectroscopically confirmed $z\approx 9.1$ galaxy MACS1149-JD1 have indicated the presence of a prominent Balmer break in its spectral energy distribution, which may be interpreted as due to very large fluctuations in its past star formation activity. In this paper, we investigate to what extent contemporary simulations of high-redshift galaxies produce star formation rate variations sufficiently large to reproduce the observed Balmer break of MACS1149-JD1. We find that several independent galaxy simulations are unable to account for Balmer breaks of the inferred size, suggesting that MACS1149-JD1 either must be a very rare type of object or that our simulations are missing some key ingredient. We present predictions of spectroscopic Balmer break strength distributions for $z\approx 7-9$ galaxies that may be tested through observations with the upcoming James Webb Space Telescope and also discuss the impact that various assumptions on dust reddening, Lyman continuum leakage and deviations from a standard stellar initial mass function would have on the results., Comment: 11 pages, 8 figures. Accepted for publication in MNRAS

Published
2019
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37. Hyper-Kamiokande Design Report

Author

Proto-Collaboration, Hyper-Kamiokande, Abe, K., Abe, Ke., Aihara, H., Aimi, A., Akutsu, R., Andreopoulos, C., Anghel, I., Anthony, L. H. V., Antonova, M., Ashida, Y., Aushev, V., Barbi, M., Barker, G. J., Barr, G., Beltrame, P., Berardi, V., Bergevin, M., Berkman, S., Berns, L., Berry, T., Bhadra, S., Bravo-Berguño, D., Blaszczyk, F. d. M., Blondel, A., Bolognesi, S., Boyd, S. B., Bravar, A., Bronner, C., Avanzini, M. Buizza, Cafagna, F. S., Cole, A., Calland, R., Cao, S., Cartwright, S. L., Catanesi, M. G., Checchia, C., Chen-Wishart, Z., Choi, J. H., Choi, K., Coleman, J., Collazuol, G., Cowan, G., Cremonesi, L., Dealtry, T., De Rosa, G., Densham, C., Dewhurst, D., Drakopoulou, E. L., Di Lodovico, F., Drapier, O., Dumarchez, J., Dunne, P., Dziewiecki, M., Emery, S., Esmaili, A., Evangelisti, A., Fernandez-Martinez, E., Feusels, T., Finch, A., Fiorentini, A., Fiorillo, G., Fitton, M., Frankiewicz, K., Friend, M., Fujii, Y., Fukuda, Y., Fukuda, D., Ganezer, K., Giganti, C., Gonin, M., Grant, N., Gumplinger, P., Hadley, D. R., Hartfiel, B., Hartz, M., Hayato, Y., Hayrapetyan, K., Hill, J., Hirota, S., Horiuchi, S., Ichikawa, A. K., Iijima, T., Ikeda, M., Imber, J., Inoue, K., Insler, J., Intonti, R. A., Ioannisian, A., Ishida, T., Ishino, H., Ishitsuka, M., Itow, Y., Iwamoto, K., Izmaylov, A., Jamieson, B., Jang, H. I., Jang, J. S., Jeon, S. H., Jiang, M., Jonsson, P., Joo, K. K., Kaboth, A., Kachulis, C., Kajita, T., Kameda, J., Kataoka, Y., Katori, T., Kayrapetyan, K., Kearns, E., Khabibullin, M., Khotjantsev, A., Kim, J. H., Kim, J. Y., Kim, S. B., Kim, S. Y., King, S., Kishimoto, Y., Kobayashi, T., Koga, M., Konaka, A., Kormos, L. L., Koshio, Y., Korzenev, A., Kowalik, K. L., Kropp, W. R., Kudenko, Y., Kurjata, R., Kutter, T., Kuze, M., Labarga, L., Lagoda, J., Lasorak, P. J. J., Laveder, M., Lawe, M., Learned, J. G., Lim, I. T., Lindner, T., Litchfield, R. P., Longhin, A., Loverre, P., Lou, T., Ludovici, L., Ma, W., Magaletti, L., Mahn, K., Malek, M., Maret, L., Mariani, C., Martens, K., Marti, Ll., Martin, J. F., Marzec, J., Matsuno, S., Mazzucato, E., McCarthy, M., McCauley, N., McFarland, K. S., McGrew, C., Mefodiev, A., Mermod, P., Metelko, C., Mezzetto, M., Migenda, J., Mijakowski, P., Minakata, H., Minamino, A., Mine, S., Mineev, O., Mitra, A., Miura, M., Mochizuki, T., Monroe, J., Moon, D. H., Moriyama, S., Mueller, T., Muheim, F., Murase, K., Muto, F., Nakahata, M., Nakajima, Y., Nakamura, K., Nakaya, T., Nakayama, S., Nantais, C., Needham, M., Nicholls, T., Nishimura, Y., Noah, E., Nova, F., Nowak, J., Nunokawa, H., Obayashi, Y., O'Keeffe, H. M., Okajima, Y., Okumura, K., Onishchuk, Yu., O'Sullivan, E., O'Sullivan, L., Ovsiannikova, T., Owen, R. A., Oyama, Y., Pac, M. Y., Palladino, V., Palomino, J. L., Paolone, V., Parker, W., Parsa, S., Payne, D., Perkin, J. D., Pidcott, C., Guerra, E. Pinzon, Playfer, S., Popov, B., Posiadala-Zezula, M., Poutissou, J. M., Pritchard, A., Prouse, N. W., Pronost, G., Przewlocki, P., Quilain, B., Radicioni, E., Ratoff, P. N., Retiere, F., Riccio, C., Richards, B., Rondio, E., Rose, H. J., Rott, C., Rountree, S. D., Ruggeri, A. C., Rychter, A., Sacco, R., Sakuda, M., Sanchez, M. C., Scantamburlo, E., Scott, M., Sedgwick, S. M., Seiya, Y., Sekiguchi, T., Sekiya, H., Seo, S. H., Sgalaberna, D., Shah, R., Shaikhiev, A., Shimizu, I., Shiozawa, M., Shitov, Y., Short, S., Simpson, C., Sinnis, G., Smy, M. B., Snow, S., Sobczyk, J., Sobel, H. W., Sonoda, Y., Spina, R., Stewart, T., Stone, J. L., Suda, Y., Suwa, Y., Suzuki, Y., Suzuki, A. T., Svoboda, R., Taani, M., Tacik, R., Takeda, A., Takenaka, A., Taketa, A., Takeuchi, Y., Takhistov, V., Tanaka, H. A., Tanaka, H. K. M., Tanaka, H., Terri, R., Thiesse, M., Thompson, L. F., Thorpe, M., Tobayama, S., Touramanis, C., Towstego, T., Tsukamoto, T., Tsui, K. M., Tzanov, M., Uchida, Y., Vagins, M. R., Vasseur, G., Vilela, C., Vogelaar, R. B., Walding, J., Walker, J., Ward, M., Wark, D., Wascko, M. O., Weber, A., Wendell, R., Wilkes, R. J., Wilking, M. J., Wilson, J. R., Xin, T., Yamamoto, K., Yanagisawa, C., Yano, T., Yen, S., Yershov, N., Yeum, D. N., Yokoyama, M., Yoshida, T., Yu, I., Yu, M., Zalipska, J., Zaremba, K., Ziembicki, M., Zito, M., and Zsoldos, S.

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Solar and Stellar Astrophysics, High Energy Physics - Experiment
Abstract

On the strength of a double Nobel prize winning experiment (Super)Kamiokande and an extremely successful long baseline neutrino programme, the third generation Water Cherenkov detector, Hyper-Kamiokande, is being developed by an international collaboration as a leading worldwide experiment based in Japan. The Hyper-Kamiokande detector will be hosted in the Tochibora mine, about 295 km away from the J-PARC proton accelerator research complex in Tokai, Japan. The currently existing accelerator will be steadily upgraded to reach a MW beam by the start of the experiment. A suite of near detectors will be vital to constrain the beam for neutrino oscillation measurements. A new cavern will be excavated at the Tochibora mine to host the detector. The experiment will be the largest underground water Cherenkov detector in the world and will be instrumented with new technology photosensors, faster and with higher quantum efficiency than the ones in Super-Kamiokande. The science that will be developed will be able to shape the future theoretical framework and generations of experiments. Hyper-Kamiokande will be able to measure with the highest precision the leptonic CP violation that could explain the baryon asymmetry in the Universe. The experiment also has a demonstrated excellent capability to search for proton decay, providing a significant improvement in discovery sensitivity over current searches for the proton lifetime. The atmospheric neutrinos will allow to determine the neutrino mass ordering and, together with the beam, able to precisely test the three-flavour neutrino oscillation paradigm and search for new phenomena. A strong astrophysical programme will be carried out at the experiment that will detect supernova neutrinos and will measure precisely solar neutrino oscillation., Comment: 325 pages

Published
2018

38. Lyman continuum leakage versus quenching with the James Webb Space Telescope: The spectral signatures of quenched star formation activity in reionization-epoch galaxies

Author

Binggeli, C., Zackrisson, E., Pelckmans, K., Cubo, R., Jensen, H., and Shimizu, I.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

In this paper, we study the effects of a recent drop in star formation rate (SFR) on the spectra of epoch of reionization (EoR) galaxies, and the resulting degeneracy with the spectral features produced by extreme Lyman continuum leakage. In order to study these effects in the wavelength range relevant for the upcoming James Webb Space Telescope (JWST), we utilize synthetic spectra of simulated EoR galaxies from cosmological simulations together with synthetic spectra of partially quenched mock galaxies. We find that rapid declines in the SFR of EoR galaxies could seriously affect the applicability of methods that utilize the equivalent width of Balmer lines and the ultraviolet spectral slope to assess the escape fraction of EoR galaxies. In order to determine if the aforementioned degeneracy can be avoided by using the overall shape of the spectrum, we generate mock NIRCam observations and utilize a classification algorithm to identify galaxies that have undergone quenching. We find that while there are problematic cases, JWST/NIRCam or NIRSpec should be able to reliably identify galaxies with redshifts $z\sim 7$ that have experienced a significant decrease in the SFR (by a factor 10-100) in the past 50-100 Myr with a success rate $\gtrsim 85\%$. We also find that uncertainties in the dust-reddening effects on EoR galaxies significantly affect the performance of the results of the classification algorithm. We argue that studies that aim to characterize the dust extinction law most representative in the EoR would be extremely useful., Comment: 10 pages, 7 figures. Accepted for publication in MNRAS

Published
2018
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39. Precision Analysis of the Xe136 Two-Neutrino ββ Spectrum in KamLAND-Zen and Its Impact on the Quenching of Nuclear Matrix Elements

Author

Gando, A, Gando, Y, Hachiya, T, Minh, M Ha, Hayashida, S, Honda, Y, Hosokawa, K, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kamizawa, K, Kinoshita, T, Koga, M, Matsuda, S, Mitsui, T, Nakamura, K, Ono, A, Ota, N, Otsuka, S, Ozaki, H, Shibukawa, Y, Shimizu, I, Shirahata, Y, Shirai, J, Sato, T, Soma, K, Suzuki, A, Takeuchi, A, Tamae, K, Ueshima, K, Watanabe, H, Chernyak, D, Kozlov, A, Obara, S, Yoshida, S, Takemoto, Y, Umehara, S, Fushimi, K, Hirata, S, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, O’Donnell, T, Detwiler, JA, Enomoto, S, Decowski, MP, Menéndez, J, Dvornický, R, and Šimkovic, F

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, KamLAND-Zen Collaboration, hep-ex, nucl-ex, nucl-th, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

We present a precision analysis of the ^{136}Xe two-neutrino ββ electron spectrum above 0.8 MeV, based on high-statistics data obtained with the KamLAND-Zen experiment. An improved formalism for the two-neutrino ββ rate allows us to measure the ratio of the leading and subleading 2νββ nuclear matrix elements (NMEs), ξ_{31}^{2ν}=-0.26_{-0.25}^{+0.31}. Theoretical predictions from the nuclear shell model and the majority of the quasiparticle random-phase approximation (QRPA) calculations are consistent with the experimental limit. However, part of the ξ_{31}^{2ν} range allowed by the QRPA is excluded by the present measurement at the 90% confidence level. Our analysis reveals that predicted ξ_{31}^{2ν} values are sensitive to the quenching of NMEs and the competing contributions from low- and high-energy states in the intermediate nucleus. Because these aspects are also at play in neutrinoless ββ decay, ξ_{31}^{2ν} provides new insights toward reliable neutrinoless ββ NMEs.

Published
2019

40. Precision Analysis of the ^{136}Xe Two-Neutrino ββ Spectrum in KamLAND-Zen and Its Impact on the Quenching of Nuclear Matrix Elements.

Author

Gando, A, Gando, Y, Hachiya, T, Ha Minh, M, Hayashida, S, Honda, Y, Hosokawa, K, Ikeda, H, Inoue, K, Ishidoshiro, K, Kamei, Y, Kamizawa, K, Kinoshita, T, Koga, M, Matsuda, S, Mitsui, T, Nakamura, K, Ono, A, Ota, N, Otsuka, S, Ozaki, H, Shibukawa, Y, Shimizu, I, Shirahata, Y, Shirai, J, Sato, T, Soma, K, Suzuki, A, Takeuchi, A, Tamae, K, Ueshima, K, Watanabe, H, Chernyak, D, Kozlov, A, Obara, S, Yoshida, S, Takemoto, Y, Umehara, S, Fushimi, K, Hirata, S, Berger, BE, Fujikawa, BK, Learned, JG, Maricic, J, Winslow, LA, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, O'Donnell, T, Detwiler, JA, Enomoto, S, Decowski, MP, Menéndez, J, Dvornický, R, Šimkovic, F, and KamLAND-Zen Collaboration

Subjects
KamLAND-Zen Collaboration, hep-ex, nucl-ex, nucl-th, General Physics, Physical Sciences
Abstract

We present a precision analysis of the ^{136}Xe two-neutrino ββ electron spectrum above 0.8 MeV, based on high-statistics data obtained with the KamLAND-Zen experiment. An improved formalism for the two-neutrino ββ rate allows us to measure the ratio of the leading and subleading 2νββ nuclear matrix elements (NMEs), ξ_{31}^{2ν}=-0.26_{-0.25}^{+0.31}. Theoretical predictions from the nuclear shell model and the majority of the quasiparticle random-phase approximation (QRPA) calculations are consistent with the experimental limit. However, part of the ξ_{31}^{2ν} range allowed by the QRPA is excluded by the present measurement at the 90% confidence level. Our analysis reveals that predicted ξ_{31}^{2ν} values are sensitive to the quenching of NMEs and the competing contributions from low- and high-energy states in the intermediate nucleus. Because these aspects are also at play in neutrinoless ββ decay, ξ_{31}^{2ν} provides new insights toward reliable neutrinoless ββ NMEs.

Published
2019

41. Erratum: “A Search for Electron Antineutrinos Associated with Gravitational-wave Events GW150914 and GW151226 Using KamLAND” (2016, ApJL, 829, L34)

Author

Gando, A, Gando, Y, Hachiya, T, Hayashi, A, Hayashida, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Karino, Y, Koga, M, Matsuda, S, Mitsui, T, Nakamura, K, Obara, S, Oura, T, Ozaki, H, Shimizu, I, Shirahata, Y, Shirai, J, Suzuki, A, Takai, T, Tamae, K, Teraoka, Y, Ueshima, K, Watanabe, H, Kozlov, A, Takemoto, Y, Yoshida, S, Fushimi, K, Piepke, A, Banks, TI, Berger, BE, Fujikawa, BK, O’Donnell, T, Learned, JG, Maricic, J, Sakai, M, Winslow, LA, Krupczak, E, Ouellet, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Detwiler, JA, Enomoto, S, and Decowski, MP

Subjects
Particle and High Energy Physics, Physical Sciences, Astronomical and Space Sciences, Astronomy & Astrophysics, Astronomical sciences, Space sciences
Published
2017

42. A Search for Electron Antineutrinos Associated with Gravitational-wave Events GW150914 and GW151226 Using KamLAND (vol 829, L34, 2016)

Author

Gando, A, Gando, Y, Hachiya, T, Hayashi, A, Hayashida, S, Ikeda, H, Inoue, K, Ishidoshiro, K, Karino, Y, Koga, M, Matsuda, S, Mitsui, T, Nakamura, K, Obara, S, Oura, T, Ozaki, H, Shimizu, I, Shirahata, Y, Shirai, J, Suzuki, A, Takai, T, Tamae, K, Teraoka, Y, Ueshima, K, Watanabe, H, Kozlov, A, Takemoto, Y, Yoshida, S, Fushimi, K, Piepke, A, Banks, TI, Berger, BE, Fujikawa, BK, O'Donnell, T, Learned, JG, Maricic, J, Sakai, M, Winslow, LA, Krupczak, E, Ouellet, J, Efremenko, Y, Karwowski, HJ, Markoff, DM, Tornow, W, Detwiler, JA, Enomoto, S, Decowski, MP, and Collaboration, KamLAND

Subjects
Astronomy & Astrophysics, Astronomical and Space Sciences
Published
2017

43. Physics Potentials with the Second Hyper-Kamiokande Detector in Korea

Author

proto-collaboration, Hyper-Kamiokande, Abe, K., Abe, Ke., Ahn, S. H., Aihara, H., Aimi, A., Akutsu, R., Andreopoulos, C., Anghel, I., Anthony, L. H. V., Antonova, M., Ashida, Y., Aushev, V., Barbi, M., Barker, G. J., Barr, G., Beltrame, P., Berardi, V., Bergevin, M., Berkman, S., Berns, L., Berry, T., Bhadra, S., no, D. Bravo-Bergu, Blaszczyk, F. d. M., Blondel, A., Bolognesi, S., Boyd, S. B., Bravar, A., Bronner, C., Avanzini, M. Buizza, Cafagna, F. S., Cheon, B. G., Cheoun, M. K., Cho, K., Choi, K. Y., Chun, E. J., Cole, A., Calland, R., Cao, S., Cartwright, S. L., Catanesi, M. G., Checchia, C., Chen-Wishart, Z., Choi, J. H., Choi, K., Coleman, J., Collazuol, G., Cowan, G., Cremonesi, L., Dealtry, T., De Rosa, G., Densham, C., Dewhurst, D., Drakopoulou, E. L., Di Lodovico, F., Drapier, O., Dumarchez, J., Dunne, P., Dziewiecki, M., Emery, S., Esmaili, A., Evangelisti, A., Fernandez-Martinez, E., Feusels, T., Finch, A., Fiorentini, G. A., Fiorillo, G., Fitton, M., Frankiewicz, K., Friend, M., Fujii, Y., Fukuda, Y., Fukuda, D., Ganezer, K., Ghosh, M., Giganti, C., Gonin, M., Grant, N., Gumplinger, P., Hadley, D. R., Hartfiel, B., Hartz, M., Hayato, Y., Hayrapetyan, K., Hill, J., Hirota, S., Horiuchi, S., Ichikawa, A. K., Iijima, T., Ikeda, M., Imber, J., Inoue, K., Insler, J., Intonti, R. A., Ioannisian, A., Ishida, T., Ishino, H., Ishitsuka, M., Itow, Y., Iwamoto, K., Izmaylov, A., Jamieson, B., Jang, H. I., Jang, J. S., Jeon, S. H., Jeong, K. S., Jiang, M., Jonsson, P., Joo, K. K., Kaboth, A., Kachulis, C., Kajita, T., Kang, S. K., Kameda, J., Kataoka, Y., Katori, T., Kayrapetyan, K., Kearns, E., Khabibullin, M., Khotjantsev, A., Kim, C. S., Kim, H. B., Kim, H. J., Kim, J. H., Kim, J. -S., Kim, J. Y., Kim, S. B., Kim, S. C., Kim, S. -W., Kim, S. Y., King, S., Kim, T. J., Kim, W., Kishimoto, Y., Ko, P., Kobayashi, T., Koga, M., Konaka, A., Kormos, L. L., Koshio, Y., Korzenev, A., Kowalik, K. L., Kropp, W. R., Kudenko, Y., Kurjata, R., Kutter, T., Kuze, M., Kwak, K., Kwon, E. H., Labarga, L., Lagoda, J., Lasorak, P. J. J., Laveder, M., Lawe, M., Learned, J. G., Lee, C. H., Lee, S. J., Lee, W. J., Lim, I. T., Lindner, T., Litchfield, R. P., Longhin, A., Loverre, P., Lou, T., Ludovici, L., Ma, W., Magaletti, L., Mahn, K., Malek, M., Maret, L., Mariani, C., Martens, K., Marti, Ll., Martin, J. F., Marzec, J., Matsuno, S., Mazzucato, E., McCarthy, M., McCauley, N., McFarland, K. S., McGrew, C., Mefodiev, A., Mermod, P., Metelko, C., Mezzetto, M., Migenda, J., Mijakowski, P., Minakata, H., Minamino, A., Mine, S., Mineev, O., Mitra, A., Miura, M., Mochizuki, T., Monroe, J., Moon, C. S., Moon, D. H., Moriyama, S., Mueller, T., Muheim, F., Murase, K., Muto, F., Nakahata, M., Nakajima, Y., Nakamura, K., Nakaya, T., Nakayama, S., Nantais, C., Needham, M., Nicholls, T., Nishimura, Y., Noah, E., Nova, F., Nowak, J., Nunokawa, H., Obayashi, Y., Oh, Y. D., Oh, Y., O'Keeffe, H. M., Okajima, Y., Okumura, K., Onishchuk, Yu., O'Sullivan, E., O'Sullivan, L., Ovsiannikova, T., Owen, R. A., Oyama, Y., Pac, M. Y., Palladino, V., Palomino, J. L., Paolone, V., Park, H. S., Park, J. C., Park, M. G., Park, S. C., Parker, W., Parsa, S., Payne, D., Perkin, J. D., Pidcott, C., Guerra, E. Pinzon, Playfer, S., Popov, B., Posiadala-Zezula, M., Poutissou, J. -M., Pritchard, A., Prouse, N. W., Pronost, G., Przewlocki, P., Quilain, B., Quinto, M., Radicioni, E., Ratoff, P. N., Retiere, F., Riccio, C., Richards, B., Rondio, E., Rose, H. J., Rott, C., Rountree, S. D., Ruggeri, A. C., Rychter, A., Ryu, D., Sacco, R., Sakuda, M., Sanchez, M. C., Scantamburlo, E., Scott, M., Sedgwick, S. Molina, Seiya, Y., Sekiguchi, T., Sekiya, H., Seo, H., Seo, S. H., Sgalaberna, D., Shah, R., Shaikhiev, A., Shimizu, I., Shiozawa, M., Shitov, Y., Short, S., Simpson, C., Sinnis, G., Smy, M. B., Snow, S., Sobczyk, J., Sobel, H. W., Son, D. C., Sonoda, Y., Spina, R., Stewart, T., Stone, J. L., Suda, Y., Suwa, Y., Suzuki, Y., Suzuki, A. T., Svoboda, R., Taani, M., Tacik, R., Takeda, A., Takenaka, A., Taketa, A., Takeuchi, Y., Takhistov, V., Tanaka, H. A., Tanaka, H. K. M., Tanaka, H., Terri, R., Thiesse, M., Thompson, L. F., Thorpe, M., Tobayama, S., Touramanis, C., Towstego, T., Tsukamoto, T., Tsui, K. M., Tzanov, M., Uchida, Y., Vagins, M. R., Vasseur, G., Vilela, C., Vogelaar, R. B., Walding, J., Walker, J., Ward, M., Wark, D., Wascko, M. O., Weber, A., Wendell, R., Wilkes, R. J., Wilking, M. J., Wilson, J. R., Won, E., Xin, T., Yamamoto, K., Yanagisawa, C., Yano, T., Yasuda, O., Yen, S., Yershov, N., Yeum, D. N., Yokoyama, M., Yoo, H. D., Yoo, J., Yoon, S. C., Yoon, T. S., Yoshida, T., Yu, I., Yu, M., Zalipska, J., Zaremba, K., Ziembicki, M., Zito, M., and Zsoldos, S.

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

Hyper-Kamiokande consists of two identical water-Cherenkov detectors of total 520~kt with the first one in Japan at 295~km from the J-PARC neutrino beam with 2.5$^{\textrm{o}}$ Off-Axis Angles (OAAs), and the second one possibly in Korea in a later stage. Having the second detector in Korea would benefit almost all areas of neutrino oscillation physics mainly due to longer baselines. There are several candidate sites in Korea with baselines of 1,000$\sim$1,300~km and OAAs of 1$^{\textrm{o}}$$\sim$3$^{\textrm{o}}$. We conducted sensitivity studies on neutrino oscillation physics for a second detector, either in Japan (JD $\times$ 2) or Korea (JD + KD) and compared the results with a single detector in Japan. Leptonic CP violation sensitivity is improved especially when the CP is non-maximally violated. The larger matter effect at Korean candidate sites significantly enhances sensitivities to non-standard interactions of neutrinos and mass ordering determination. Current studies indicate the best sensitivity is obtained at Mt. Bisul (1,088~km baseline, $1.3^\circ$ OAA). Thanks to a larger (1,000~m) overburden than the first detector site, clear improvements to sensitivities for solar and supernova relic neutrino searches are expected., Comment: 102 pages, 49 figures. Accepted by PTEP

Published
2016
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44. The spectral evolution of the first Galaxies. III. Simulated James Webb Space Telescope spectra of reionization-epoch galaxies with Lyman continuum leakage

Author

Zackrisson, E., Binggeli, C., Finlator, K., Gnedin, N. Y., Paardekooper, J. -P., Shimizu, I., Inoue, A. K., Jensen, H., Micheva, G., Khochfar, S., and Vecchia, C. Dalla

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Using four different suites of cosmological simulations, we generate synthetic spectra for galaxies with different Lyman continuum escape fractions (fesc) at redshifts z=7-9, in the rest-frame wavelength range relevant for the James Webb Space Telescope (JWST) NIRSpec instrument. By investigating the effects of realistic star formation histories and metallicity distributions on the EW(Hb)-beta diagram (previously proposed as a tool for identifying galaxies with very high fesc), we find that neither of these effects are likely to jeopardize the identification of galaxies with extreme Lyman continuum leakage. Based on our models, we expect essentially all z=7-9 galaxies that exhibit rest-frame EW(Hb)< 30 {\AA} to have fesc>0.5. Incorrect assumptions concerning the ionizing fluxes of stellar populations or the dust properties of z>6 galaxies can in principle bias the selection, but substantial model deficiencies of this type will at the same time reveal themselves as an offset between the observed and simulated distribution of z>6 galaxies in the EW(Hb)-beta diagram. Such offsets would thereby allow JWST/NIRSpec measurements of these observables to serve as input for further model refinement., Comment: 12 pages, 8 figures, v.2: ApJ, accepted. Model grids are available from http://www.astro.uu.se/~ez/lycan/lycan.html

Published
2016
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45. Search for electron antineutrinos associated with gravitational wave events GW150914 and GW151226 using KamLAND

Author

KamLAND Collaboration, Gando, A., Gando, Y., Hachiya, T., Hayashi, A., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Karino, Y., Koga, M., Matsuda, S., Mitsui, T., Nakamura, K., Obara, S., Oura, T., Ozaki, H., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Takai, T., Tamae, K., Teraoka, Y., Ueshima, K., Watanabe, H., Kozolov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Piepke, A., Banks, T. I., Berger, B. E., Fujikawa, B. K., O'Donnell, T., Learned, J. G., Maricic, J., Sakai, M., Winslow, L. A., Krupczak, E., Ouellet, J., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P.

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

We present a search for low energy antineutrino events coincident with the gravitational wave events GW150914 and GW151226, and the candidate event LVT151012 using KamLAND, a kiloton-scale antineutrino detector. We find no inverse beta-decay neutrino events within $\pm 500$ seconds of either gravitational wave signal. This non-detection is used to constrain the electron antineutrino fluence and the luminosity of the astrophysical sources., Comment: 11 pages, 4 figures, as published in ApJL. Updated to replace power law spectrum with Fermi Dirac spectrum

Published
2016
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46. THE AGORA HIGH-RESOLUTION GALAXY SIMULATIONS COMPARISON PROJECT. II. ISOLATED DISK TEST

Author

Kim, JH, Agertz, O, Teyssier, R, Butler, MJ, Ceverino, D, Choi, JH, Feldmann, R, Keller, BW, Lupi, A, Quinn, T, Revaz, Y, Wallace, S, Gnedin, NY, Leitner, SN, Shen, S, Smith, BD, Thompson, R, Turk, MJ, Abel, T, Arraki, KS, Benincasa, SM, Chakrabarti, S, Degraf, C, Dekel, A, Goldbaum, NJ, Hopkins, PF, Hummels, CB, Klypin, A, Li, H, Madau, P, Mandelker, N, Mayer, L, Nagamine, K, Nickerson, S, O'Shea, BW, Primack, JR, Roca-Fàbrega, S, Semenov, V, Shimizu, I, Simpson, CM, Todoroki, K, Wadsley, JW, and Wise, JH

Subjects
cosmology: theory, galaxies: evolution, galaxies: formation, galaxies: kinematics and dynamics, ISM: structure, methods: numerical, astro-ph.GA, astro-ph.CO, Astronomy & Astrophysics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Physical Chemistry (incl. Structural)
Abstract

Using an isolated Milky Way-mass galaxy simulation, we compare results from nine state-of-the-art gravito-hydrodynamics codes widely used in the numerical community. We utilize the infrastructure we have built for the AGORA High-resolution Galaxy Simulations Comparison Project. This includes the common disk initial conditions, common physics models (e.g., radiative cooling and UV background by the standardized package Grackle) and common analysis toolkit yt, all of which are publicly available. Subgrid physics models such as Jeans pressure floor, star formation, supernova feedback energy, and metal production are carefully constrained across code platforms. With numerical accuracy that resolves the disk scale height, we find that the codes overall agree well with one another in many dimensions including: gas and stellar surface densities, rotation curves, velocity dispersions, density and temperature distribution functions, disk vertical heights, stellar clumps, star formation rates, and Kennicutt-Schmidt relations. Quantities such as velocity dispersions are very robust (agreement within a few tens of percent at all radii) while measures like newly formed stellar clump mass functions show more significant variation (difference by up to a factor of ∼3). Systematic differences exist, for example, between mesh-based and particle-based codes in the low-density region, and between more diffusive and less diffusive schemes in the high-density tail of the density distribution. Yet intrinsic code differences are generally small compared to the variations in numerical implementations of the common subgrid physics such as supernova feedback. Our experiment reassures that, if adequately designed in accordance with our proposed common parameters, results of a modern high-resolution galaxy formation simulation are more sensitive to input physics than to intrinsic differences in numerical schemes.

Published
2016

47. IsoDAR@KamLAND: A Conceptual Design Report for the Technical Facility

Author

Abs, M., Adelmann, A., Alonso, J. R, Axani, S., Barletta, W. A., Barlow, R., Bartoszek, L., Bungau, A., Calabretta, L., Calanna, A., Campo, D., Castro, G., Celona, L., Collin, G. H., Conrad, J. M., Gammino, S., Johnson, R., Karagiorgi, G., Kayser, S., Kleeven, W., Kolano, A., Labrecque, F., Loinaz, W. A., Minervini, J., Moulai, M. H., Okuno, H., Owen, H., Papavassiliou, V., Shaevitz, M. H., Shimizu, I., Shokair, T. M., Sorensen, K. F., Spitz, J., Toups, M., Vagins, M., Van Bibber, K., Wascko, M. O., Winklehner, D., Winslow, L. A, and Yang, J. J.

Subjects
Physics - Accelerator Physics, High Energy Physics - Experiment
Abstract

This conceptual design report describes the technical facility for the IsoDAR electron-antineutrino source at KamLAND. The IsoDAR source will allow an impressive program of neutrino oscillation and electroweak physics to be performed at KamLAND. This report provides information on the physics case, the conceptual design for the subsystems, alternative designs considered, specifics of installation at KamLAND, and identified needs for future development. We discuss the risks we have identified and our approach to mitigating those risks with this design. A substantial portion of the conceptual design is based on three years of experimental efforts and on industry experience. This report also includes information on the conventional facilities.

Published
2015

48. Search for double-beta decay of 136Xe to excited states of 136Ba with the KamLAND-Zen experiment

Author

Collaboration, KamLAND-Zen, Asakura, K., Gando, A., Gando, Y., Hachiya, T., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Ishikawa, T., Ishio, S., Koga, M., Matsuda, S., Mitsui, T., Motoki, D., Nakamura, K., Obara, S., Otani, M., Oura, T., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Tachibana, H., Tamae, K., Ueshima, K., Watanabe, H., Xu, B. D., Yoshida, H., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Banks, T. I., Berger, B. E., Fujikawa, B. K., O'Donnell, T., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P.

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

A search for double-beta decays of 136Xe to excited states of 136Ba has been performed with the first phase data set of the KamLAND-Zen experiment. The 0+1, 2+1 and 2+2 transitions of 0{\nu}\{beta}\{beta} decay were evaluated in an exposure of 89.5kg-yr of 136Xe, while the same transitions of 2{\nu}\{beta}\{beta} decay were evaluated in an exposure of 61.8kg-yr. No excess over background was found for all decay modes. The lower half-life limits of the 2+1 state transitions of 0{\nu}\{beta}\{beta} and 2{\nu}\{beta}\{beta} decay were improved to T(0{\nu}, 0+ \rightarrow 2+) > 2.6\times10^25 yr and T(2{\nu}, 0+ \rightarrow 2+) > 4.6\times10^23 yr (90% C.L.), respectively. We report on the first experimental lower half-life limits for the transitions to the 0+1 state of 136Xe for 0{\nu}\{beta}\{beta} and 2{\nu}\{beta}\{beta} decay. They are T (0{\nu}, 0+ \rightarrow 0+) > 2.4\times10^25 yr and T(2{\nu}, 0+ \rightarrow 0+) > 8.3\times10^23 yr (90% C.L.). The transitions to the 2+2 states are also evaluated for the first time to be T(0{\nu}, 0+ \rightarrow 2+) > 2.6\times10^25 yr and T(2{\nu}, 0+ \rightarrow 2+) > 9.0\times10^23 yr (90% C.L.). These results are compared to recent theoretical predictions., Comment: 16 pages, 4 figures. Published in Nuclear Physics A

Published
2015
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49. KamLAND Sensitivity to Neutrinos from Pre-Supernova Stars

Author

Asakura, K., Gando, A., Gando, Y., Hachiya, T., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Ishikawa, T., Ishio, S., Koga, M., Matsuda, S., Mitsui, T., Motoki, D., Nakamura, K., Obara, S., Oura, T., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Tachibana, H., Tamae, K., Ueshima, K., Watanabe, H., Xu, B. D., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Piepke, A., Banks, T. I., Berger, B. E., Fujikawa, B. K., O'Donnell, T., Learned, J. G., Maricic, J., Matsuno, S., Sakai, M., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P.

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

In the late stages of nuclear burning for massive stars ($M>8~M_{\sun}$), the production of neutrino-antineutrino pairs through various processes becomes the dominant stellar cooling mechanism. As the star evolves, the energy of these neutrinos increases and in the days preceding the supernova a significant fraction of emitted electron anti-neutrinos exceeds the energy threshold for inverse beta decay on free hydrogen. This is the golden channel for liquid scintillator detectors because the coincidence signature allows for significant reductions in background signals. We find that the kiloton-scale liquid scintillator detector KamLAND can detect these pre-supernova neutrinos from a star with a mass of $25~M_{\sun}$ at a distance less than 690~pc with 3$\sigma$ significance before the supernova. This limit is dependent on the neutrino mass ordering and background levels. KamLAND takes data continuously and can provide a supernova alert to the community., Comment: 19 pages, 6 figures, 1 table

Published
2015
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50. The ALMA Patchy Deep Survey: A blind search for [CII] emitters at z~4.5

Author

Matsuda, Y., Nagao, T., Iono, D., Hatsukade, B., Kohno, K., Tamura, Y., Yamaguchi, Y., and Shimizu, I.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present a result of a blind search for [CII] 158 $\mu$m emitters at $z\sim 4.5$ using ALMA Cycle~0 archival data. We collected extra-galactic data covering at 330-360 GHz (band~7) from 8 Cycle~0 projects from which initial results have been already published. The total number of fields is 243 and the total on-source exposure time is 19.2 hours. We searched for line emitters in continuum-subtracted data cubes with spectral resolutions of 50, 100, 300 and 500 km/s. We could not detect any new line emitters above a 6-$\sigma$ significance level. This result provides upper limits to the [CII] luminosity function at $z\sim 4.5$ over $L_{\rm [CII]} \sim 10^8 - 10^{10} L_{\odot}$ or star formation rate, SFR $\sim$ 10-1000 M$_{^\odot}$/yr. These limits are at least 2 orders of magnitude larger than the [CII] luminosity functions expected from the $z \sim 4$ UV luminosity function or from numerical simulation. However, this study demonstrates that we would be able to better constrain the [CII] luminosity function and to investigate possible contributions from dusty galaxies to the cosmic star-formation rate density by collecting Cycle~1+2 archival data as the ALMA Patchy Deep Survey., Comment: 6 pages, 3 figures, accepted for publication in MNRAS

Published
2015
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