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1. Habitable Worlds Formed at Cosmic Dawn

Author

Whalen, Daniel J., Vorobyov, Eduard I., Latif, Muhammad A., Jessop, Christopher, Matsukoba, Ryoki, Hosokawa, Takashi, Skliarevskii, Alexander M., Nandal, Devesh, and Herrington, Nicholas P.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Primordial supernovae were the first, great nucleosynthetic engines in the Universe, forging the elements required for the later formation of planets and life. Here we show that planetesimals, the precursors of terrestrial planets, formed around low-mass stars in the debris of the first cosmic explosions 200 Myr after the Big Bang, before the first galaxies and far earlier than previously thought. A dense core in one of these explosions collapsed to a protoplanetary disk in which several Earth masses of planetesimals formed 0.46 - 1.66 AU from their parent 0.7 M$_{\odot}$ star, where equilibrium temperatures varied from 269 K to 186 K, in water mass fractions that were only a factor of a few less than in the Solar System today. Habitable worlds thus formed among the first generation of stars in the Universe, before the advent of the first galaxies., Comment: 32 pages, 15 figures

Published
2025

2. Improved measurements of neutron lifetime with cold neutron beam at J-PARC

Author

Fuwa, Y., Hasegawa, T., Hirota, K., Hoshino, T., Hosokawa, R., Ichikawa, G., Ieki, S., Ino, T., Iwashita, Y., Kitaguchi, M., Kitahara, R., Makise, S., Mishima, K., Mogi, T., Nagakura, N., Oide, H., Okabe, H., Otono, H., Seki, Y., Sekiba, D., Shima, T., Shimizu, H. E., Shimizu, H. M., Sumi, N., Sumino, H., Tanida, M., Uehara, H., Yamada, T., Yamashita, S., Yano, K., and Yoshioka, T.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The ``neutron lifetime puzzle'' arises from the discrepancy between neutron lifetime measurements obtained using the beam method, which measures decay products, and the bottle method, which measures the disappearance of neutrons. To resolve this puzzle, we conducted an experiment using a pulsed cold neutron beam at J-PARC. In this experiment, the neutron lifetime is determined from the ratio of neutron decay counts to $^3$He(n,p)$^3$H reactions in a gas detector. This experiment belongs to the beam method but differs from previous experiments that measured protons, as it instead detects electrons, enabling measurements with distinct systematic uncertainties. By enlarging the beam transport system and reducing systematic uncertainties, we achieved a fivefold improvement in precision. Analysis of all acquired data yielded a neutron lifetime of $\tau_{\rm n}=877.2~\pm~1.7_{\rm(stat.)}~^{+4.0}_{-3.6}{}_{\rm (sys.)}$ s. This result is consistent with bottle method measurements but exhibits a 2.3$\sigma$ tension with the average value obtained from the proton-detection-based beam method., Comment: 7 pages, 4 figures

Published
2024

3. Multiwavelength Observations of the Black Hole X-ray Binary MAXI J1820$+$070 in the Rebrightening Phase

Author

Yoshitake, Tomohiro, Shidatsu, Megumi, Ueda, Yoshihiro, Mineshige, Shin, Murata, Katsuhiro L., Adachi, Ryo, Maehara, Hiroyuki, Nogami, Daisaku, Negoro, Hitoshi, Kawai, Nobuyuki, Niwano, Masafumi, Hosokawa, Ryohei, Saito, Tomoki, Oasa, Yumiko, Takarada, Takuya, Shigeyoshi, Takumi, and Collaboration, OISTER

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the results of quasi-simultaneous multiwavelength (near-infrared, optical, UV, and X-ray) observations of the Galactic X-ray black hole binary MAXI J1820+070 performed in 2019 May 10-13, $\sim 60$ days after the onset of the first rebrightening phase. It showed a much larger optical-to-X-ray luminosity ratio ($\sim 8$) than in the initial outburst epoch. The primary components of the spectral energy distribution (SED) can be best interpreted by radiatively inefficient accretion flow (RIAF) spectrum showing a luminosity peak in the optical band. By comparison with theoretical calculations, we estimate the mass accretion rate to be $\dot{M}/(8 L_{\rm Edd}/c^2) \sim 10^{-3}$, where $c$ is the light speed and $L_{\rm Edd}$ is the Eddington luminosity. In addition to the RIAF emission, a blue power-law component is detected in the optical-UV SED, which is most likely synchrotron radiation from the jet. The optical spectrum taken at the Seimei telescope shows a weak and narrow H$\alpha$ emission line, whose emitting region is constrained to be $\gtrsim 2 \times 10^{4}$ times the gravitational radius. We suggest that the entire disk structure cannot be described by a single RIAF solution but cooler material responsible for the H$\alpha$ emission must exist at the outermost region., Comment: 11 pages, 5 figures, Published in PASJ in 2022

Published
2024
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4. Simulation Tool Development and Sensitivity Analysis of 160Gd Double Beta Decay Search by the PIKACHU Project

Author

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

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

Neutrinoless double beta decay (0v2b) has been investigated as a physical process that can provide evidence for the Majorana nature of neutrinos. The theoretical predictions of the 0v2b rate are subject to significant uncertainty, primarily due to nuclear matrix elements (NME). To reduce this uncertainty, experimental measurements of the half-lives of two-neutrino double beta decay (2v2b) in various nuclei are essential as a benchmark for NME calculations. The PIKACHU (Pure Inorganic scintillator experiment in KAmioka for CHallenging Underground sciences) project searches for the previously unobserved 2v2b decay of 160Gd, employing Ce-doped Gd3Ga3Al2O12 (GAGG) single crystals. In the Phase 1 experiment, we aim to improve the current lower limit on the 2v2b half-life of 160Gd by a prior study using a Ce-doped Gd2SiO5 (GSO) crystal. Ultimately, in Phase 2, the project seeks to achieve a sensitivity surpassing the theoretical prediction of 7.4 x 10^20 years, enabling the potential discovery of the 160Gd 2v2b decay. In this paper, we describe the development of background models based on GEANT4 simulations. The modeled backgrounds are contributions from uranium and thorium decay chains, 40K present in GAGG, and 40K gamma-rays from outside of GAGG. Additionally, we developed models for both 2v2b and 0v2b decay by implementing the theoretical kinematics of two-electron emission in double beta decay in the GEANT4 simulation. As a result, our background models successfully reproduced the measured background spectrum through fitting. By generating pseudo background spectra expected in Phase 1 and analyzing them with the combined background and 2v2b models, we evaluated the 2v2b sensitivity of Phase 1 to be 2.78 x 10^19 years (90% C.L.). This paper presents the development of these simulation models and the expected sensitivities for both Phase 1 and Phase 2 based on the pseudo data analyses., Comment: 18 pages, 12 figures

Published
2024

5. Secret of Longevity: Protoplanetary Disks as a Source of Gas in Debris Disk

Author

Ooyama, Wataru, Nakatani, Riouhei, Hosokawa, Takashi, Mitani, Hiroto, and Turner, Neal J.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

While protoplanetary disks (PPDs) are generally thought to dissipate within several Myr, recent observations have revealed gas in debris disks. The origin of this gas remains uncertain, with one possibility being the unexpectedly long survival of PPDs (the primordial-origin scenario). To explore the plausibility of this scenario, we conduct 1D disk evolution simulations, varying parameters like stellar mass, disk mass, turbulent stress, and magnetohydrodynamic winds, while incorporating stellar evolution to account for time-varying photoevaporation rates. Our focus is on disks where small grains are depleted, as these are potentially long-lived due to reduced far-ultraviolet photoevaporation. Our results show that gas in these disks can survive beyond 10 Myr regardless of the stellar mass, provided they are initially massive ($M_{\mathrm{disk}}\approx 0.1M_*$) with relatively weak turbulent stress ($\alpha \ll 10^{-2}$). The longest lifetimes are consistently found for $M_* = 2 M_{\odot}$ across a wide parameter space, with gas typically persisting at $\sim 10$--$10^3 \mathrm{au}$. Roughly estimated CO masses for these disks fall within the observed range for the most massive gas-rich debris disks around early A stars. These alignments support the plausibility of the primordial-origin scenario. Additionally, our model predicts that accretion persists for as long as the disk survives, which could explain the accretion signatures detected in old disks hosted by low-mass stars, including Peter Pan disks. Our finding also suggests that ongoing accretion may exist in gas-rich debris disks. Thus, searching for accretion signatures could be a key factor to identifying the origin of gas in debris disks., Comment: 20 pages, 16 figures

Published
2024

6. Differentiable Modeling of Planet and Substellar Atmosphere: High-Resolution Emission, Transmission, and Reflection Spectroscopy with ExoJAX2

Author

Kawahara, Hajime, Kawashima, Yui, Tada, Shotaro, Ishikawa, Hiroyuki Tako, Hosokawa, Ko, Kasagi, Yui, Kotani, Takayuki, Masuda, Kento, Nuguroho, Stevanus, Tamura, Motohide, Yama, Hibiki, Kitzmann, Daniel, Minesi, Nicolas, and Morris, Brett M.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

Modeling based on differentiable programming holds great promise for astronomy, as it can employ techniques such as Hamiltonian Monte Carlo, gradient-based optimization, and other machine learning techniques. This new programming paradigm has motivated us to develop the first auto-differentiable spectrum model of exoplanets and brown dwarfs, ExoJAX (Kawahara et al. 2022). ExoJAX is designed to directly calculate cross-sections as functions of temperature and pressure, rather than interpolating tabulated data, to minimize errors in high-dispersion spectra modeling. However, its application was primarily proof-of-concept and limited to narrowband high-dispersion emission spectroscopy. In this paper, we have enhanced the differentiable opacity calculation using a new fast and memory-efficient algorithm, and have developed differentiable radiative transfer schemes, including emission, transmission, and reflection spectroscopy. These enhancements significantly expand the range of applications, as demonstrated through actual atmospheric retrievals: high-dispersion emission spectra of the brown dwarf GL229 B, medium-dispersion transmission spectra of the hot Saturn WASP-39 b from JWST, and high-dispersion reflection spectra of Jupiter. We obtained a C/O ratio for GL229 B consistent with its host star, constrained WASP-39 b's radial velocity from molecular fine structures at original resolution ($R \sim 3,000$), and estimated Jupiter's metallicity consistent with previous studies., Comment: 32 pages, 12 figures, submitted. ExoJAX is available at https://github.com/HajimeKawahara/exojax. ExoJAX2 is scheduled to be released after the review process

Published
2024

7. Semicircular-aperture illumination scanning transmission electron microscopy

Author

Yasuhara, Akira, Hosokawa, Fumio, Asaoka, Sadayuki, Akiyama, Teppei, Iyoda, Tomokazu, Nakayama, Chikako, and Sannomiya, Takumi

Subjects
Physics - Optics, Physics - Instrumentation and Detectors
Abstract

Scanning transmission electron microscopy (STEM) provides high-resolution visualization of atomic structures as well as various functional imaging modes utilizing phase contrast. In this study we introduce a semicircular aperture in STEM bright field imaging, which gives a phase contrast transfer function that becomes complex and includes both lower and higher spatial frequency contrast transfer. This approach offers significant advantages over conventional phase plate methods, having no charge accumulation, degradation, or unwanted background noise, which are all problematic in the phase plate material. Also compared to the differential phase contrast or ptychography equipment, this semicircular aperture is far less costly. We apply this approach to visualization of polymer, biological and magnetic samples.

Published
2024
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8. Search for proton decay via $p\rightarrow{e^+\eta}$ and $p\rightarrow{\mu^+\eta}$ with a 0.37 Mton-year exposure of Super-Kamiokande

Author

Collaboration, Super-Kamiokande, Taniuchi, N., Abe, K., Abe, S., Asaoka, Y., Bronner, C., Harada, M., 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., Nakayama, S., Noguchi, Y., Pronost, G., Okamoto, K., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Mirabito, J., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Kim, J. Y., Lee, S. H., Lim, I. T., Moon, D. H., Park, R. G., Yang, B. S., Bodur, B., Scholberg, K., Walter, C. W., Beauchêne, A., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Calabria, N. F., Catanesi, M. G., Radicioni, E., Langella, A., De Rosa, G., Collazuol, G., Feltre, M., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Périssé, L., Quilain, B., Fujisawa, C., Horiuchi, S., Kobayashi, M., Liu, Y. M., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Yrey, A. Portocarrero, Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Boschi, T., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Taani, M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Yamamoto, S., Zhong, H., Feng, J., Feng, L., Han, S., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Yanagisawa, C., Hino, Y., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Stone, O., Stowell, P., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Kim, S. B., Kwon, E., Lee, M. W., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Koshiba, M., Eguchi, A., Goto, S., Iwamoto, K., Mizuno, Y., Muro, T., Nakagiri, K., Nakajima, Y., Shima, S., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesús-Valls, C., Martens, K., Marti, Ll., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Terada, K., Asaka, R., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Yoshida, T., Nakano, Y., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Wu, Y., Xu, B. D., Zhang, A. Q., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Minamino, A., Pintaudi, G., Sano, S., Sasaki, R., Shibayama, R., Shimamura, R., Suzuki, S., and Wada, K.

Subjects
High Energy Physics - Experiment
Abstract

A search for proton decay into $e^+/\mu^+$ and a $\eta$ meson has been performed using data from a 0.373 Mton$\cdot$year exposure (6050.3 live days) of Super-Kamiokande. Compared to previous searches this work introduces an improved model of the intranuclear $\eta$ interaction cross section, resulting in a factor of two reduction in uncertainties from this source and $\sim$10\% increase in signal efficiency. No significant data excess was found above the expected number of atmospheric neutrino background events resulting in no indication of proton decay into either mode. Lower limits on the proton partial lifetime of $1.4\times\mathrm{10^{34}~years}$ for $p\rightarrow e^+\eta$ and $7.3\times\mathrm{10^{33}~years}$ for $p\rightarrow \mu^+\eta$ at the 90$\%$ C.L. were set. These limits are around 1.5 times longer than our previous study and are the most stringent to date.

Published
2024

10. 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

11. Sequential formation of supermassive stars and heavy seed BHs through the interplay of cosmological cold accretion and stellar radiative feedback

Author

Kiyuna, Masaki, Hosokawa, Takashi, and Chon, Sunmyon

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

Supermassive stars (SMSs) and heavy seed black holes, as their remnants, are promising candidates for Supermassive Black Hole (SMBH) progenitors, especially for ones observed in the early universe $ z\simeq 8.5-10$ by recent JWST observations. Expected cradles of SMSs are the atomic cooling halos ($M_{\rm halo}\simeq 10^7~{\rm M_\odot}$), where "cold accretion" emerges and possibly forms SMSs. We perform a suit of cosmological radiation hydrodynamics simulations and investigate star formation after the emergence of cold accretion, solving radiative feedback from stars inside the halo. We follow the mass growth of the protostars for $\sim 3~{\rm Myr}$, resolving the gas inflow down to $\sim 0.1~{\rm pc}$ scales. We discover that, after cold accretion emerges, multiple SMSs of $m_\star \gtrsim 10^5{\rm M_\odot}$ form at the halo centre with the accretion rates maintained at $\dot{m}_\star \simeq 0.04~{\rm M_\odot}~{\rm yr^{-1}}$ for $\lesssim 3~{\rm Myr}$. Cold accretion supplies gas at a rate of $\dot{M}_{\rm gas}\gtrsim 0.01-0.1~{\rm M_\odot}~{\rm yr^{-1}}$ from outside the halo virial radius to the central gas disc. Gravitational torques from spiral arms transport gas further inward, which feeds the SMSs. Radiative feedback from stars suppresses H$_2$ cooling and disc fragmentation, while photoevaporation is prevented by a dense envelope, which attenuates ionising radiation. Our results suggest that cold accretion can bring efficient BH mass growth after seed formation in the later universe. Moreover, cold accretion and gas migration inside the central disc increase the mass concentration and provide a promising formation site for the extremely compact stellar clusters observed by JWST., Comment: 19 pages, 15 figures, accepted by MNRAS

Published
2024

12. MASTER OT J030227.28+191754.5: an unprecedentedly energetic dwarf nova outburst

Author

Tampo, Yusuke, Kato, Taichi, Isogai, Keisuke, Kimura, Mariko, Kojiguchi, Naoto, Nogami, Daisaku, Ito, Junpei, Shibata, Masaaki, Yamanaka, Masayuki, Taguchi, Kenta, Maehara, Hiroyuki, Itoh, Hiroshi, Matsumoto, Katsura, Nakagawa, Momoka, Nishida, Yukitaka, Dvorak, Shawn, Murata, Katsuhiro L., Hosokawa, Ryohei, Imai, Yuri, Ito, Naohiro, Niwano, Masafumi, Sato, Shota, Noto, Ryotaro, Yamaguchi, Ryodai, Schramm, Malte, Oasa, Yumiko, Kanai, Takahiro, Sasaki, Yu, Tordai, Tamás, Vanmunster, Tonny, Kiyota, Seiichiro, Katysheva, Nataly, Shugarov, Sergey Yu., Zubareva, Alexandra M., Antipin, Sergei, Ikonnikova, Natalia, Belinski, Alexandr, Dubovsky, Pavol A., Medulka, Tomáš, Takahashi, Jun, Takayama, Masaki, Ohshima, Tomohito, Saito, Tomoki, Tozuka, Miyako, Sako, Shigeyuki, Tanaka, Masaomi, Tominaga, Nozomu, Horiuchi, Takashi, Hanayama, Hidekazu, Reichart, Daniel E., Kouprianov, Vladimir V., Davidson Jr, James W., Caton, Daniel B., Romanov, Filipp D., Lane, David J., Hambsch, Franz-josef, Narita, Norio, Fukui, Akihiko, Ikoma, Masahiro, Tamura, Motohide, Kawabata, Koji S., Nakaoka, Tatsuya, and Imazawa, Ryo

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present a detailed study of the MASTER OT J030227.28+191754.5 outburst in 2021-2022, reaching an amplitude of 10.2 mag and a duration of 60 d. The detections of (1) the double-peaked optical emission lines, and (2) the early and ordinary superhumps, established that MASTER OT J030227.28+191754.5 is an extremely energetic WZ Sge-type dwarf nova (DN). Based on the superhump observations, we obtained its orbital period and mass ratio as 0.05986(1) d and 0.063(1), respectively. These are within a typical range of low-mass-ratio DNe. According to the binary parameters derived based on the thermal-tidal instability model, our analyses showed that (1) the standard disk model requires an accretion rate $\simeq$ 10$^{20}$ g s$^{-1}$ to explain its peak optical luminosity and (2) large mass was stored in the disk at the outburst onset. These cannot be explained solely by the impact of its massive ($\gtrsim$ 1.15 M$_\odot$) primary white dwarf implied by Kimura et al. (2023). Instead, we propose that the probable origin of this enormously energetic DN outburst is the even lower quiescence viscosity than other WZ Sge-type DNe. This discussion is qualitatively valid for most possible binary parameter spaces unless the inclination is low ($\lesssim 40^\circ$) enough for the disk to be bright explaining the outburst amplitude. Such low inclinations, however, would not allow detectable amplitude of early superhumps in the current thermal-tidal instability model. The optical spectra at outburst maximum showed the strong emission lines of Balmer, He I, and He II series whose core is narrower than $\sim 800$ km s$^{-1}$. Considering its binary parameters, a Keplerian disk cannot explain this narrow component, but the presumable origin is disk winds., Comment: 23 pages, 13 figures, 2 tables. Accepted by PASJ. Part of the online supplemental information is included

Published
2024

13. An Analytic Model of Gravitational Collapse Induced by Radiative Cooling: Instability Scale, Infall Velocity, and Accretion Rate

Author

Gurian, James, Liu, Boyuan, Jeong, Donghui, Hosokawa, Takashi, Hirano, Shingo, and Yoshida, Naoki

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

We present an analytic description of the spherically symmetric gravitational collapse of radiatively cooling gas clouds, which illustrates the mechanism by which radiative cooling induces gravitational instability at a characteristic mass scale determined by the microphysics of the gas. The approach is based on developing the "one-zone" density-temperature relationship of the gas into a full dynamical model. We convert this density-temperature relationship into a barotropic equation of state, which we use to calculate the density and velocity profiles of the gas. From these quantities, we calculate the time-dependent mass accretion rate onto the center of the cloud. The approach clarifies the mechanism by which radiative cooling induces gravitational instability. In particular, we distinguish the rapid, quasi-equilibrium contraction of a cooling gas core to high central densities from the legitimate instability this contraction establishes in the envelope. We develop a refined criterion for the mass scale of this instability, based only on the chemical-thermal evolution in the core. We explicate our model in the context of a primordial mini-halo cooled by molecular hydrogen, and then provide two further examples, a delayed collapse with hydrogen deuteride cooling and the collapse of an atomic cooling halo. In all three cases, we show that our results agree well with full hydrodynamical treatments., Comment: 13+5 pages, 14+5 figures, accepted for publication in MNRAS

Published
2024

14. Towards a universal analytical model for Population III star formation: interplay between feedback and fragmentation

Author

Liu, Boyuan, Gurian, James, Inayoshi, Kohei, Hirano, Shingo, Hosokawa, Takashi, Bromm, Volker, and Yoshida, Naoki

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

JWST has brought us new insights into Cosmic Dawn with tentative detection of the unique signatures of metal-free Population III (Pop III) stars, such as strong HeII emission, extremely blue UV spectrum, and enhanced nitrogen abundance. Self-consistent theoretical predictions of the formation rates, sites, and masses of Pop III stars are crucial for interpreting the observations, but are challenging due to complex physical processes operating over the large range of length scales involved. One solution is to combine analytical models for the small-scale star formation process with cosmological simulations that capture the large-scale physics such as structure formation, radiation backgrounds, and baryon-dark matter streaming motion that regulate the conditions of Pop III star formation. We build an analytical model to predict the final masses of Pop III stars/clusters from the properties of star-forming clouds, based on the key results of small-scale star formation simulations and stellar evolution models. Our model for the first time considers the interplay between feedback and fragmentation and covers different modes of Pop III star formation ranging from ordinary small ($\sim 10-2000\ \rm M_\odot$) clusters in molecular-cooling clouds to massive ($\gtrsim 10^{4}\ \rm M_\odot$) clusters containing supermassive ($\sim 10^{4}-3\times 10^{5}\ \rm M_\odot$) stars under violent collapse of atomic-cooling clouds. As an example, the model is applied to the Pop III star-forming clouds in the progenitors of typical haloes hosting high-$z$ luminous quasars, which shows that formation of Pop III massive clusters is common ($\sim 20-70\%$) in such biased ($\sim4\sigma$) regions, and the resulting heavy black hole seeds from supermassive stars can account for a significant fraction of observed luminous ($\gtrsim 10^{46}\ \rm erg\ s^{-1}$) quasars at $z\sim 6$., Comment: 15+8 pages, 9 + 14 figures, accepted for publication in MNRAS

Published
2024

15. LLM-jp: A Cross-organizational Project for the Research and Development of Fully Open Japanese LLMs

Author

LLM-jp, Aizawa, Akiko, Aramaki, Eiji, Chen, Bowen, Cheng, Fei, Deguchi, Hiroyuki, Enomoto, Rintaro, Fujii, Kazuki, Fukumoto, Kensuke, Fukushima, Takuya, Han, Namgi, Harada, Yuto, Hashimoto, Chikara, Hiraoka, Tatsuya, Hisada, Shohei, Hosokawa, Sosuke, Jie, Lu, Kamata, Keisuke, Kanazawa, Teruhito, Kanezashi, Hiroki, Kataoka, Hiroshi, Katsumata, Satoru, Kawahara, Daisuke, Kawano, Seiya, Keyaki, Atsushi, Kiryu, Keisuke, Kiyomaru, Hirokazu, Kodama, Takashi, Kubo, Takahiro, Kuga, Yohei, Kumon, Ryoma, Kurita, Shuhei, Kurohashi, Sadao, Li, Conglong, Maekawa, Taiki, Matsuda, Hiroshi, Miyao, Yusuke, Mizuki, Kentaro, Mizuki, Sakae, Murawaki, Yugo, Mousterou, Akim, Nakamura, Ryo, Nakamura, Taishi, Nakayama, Kouta, Nakazato, Tomoka, Niitsuma, Takuro, Nishitoba, Jiro, Oda, Yusuke, Ogawa, Hayato, Okamoto, Takumi, Okazaki, Naoaki, Oseki, Yohei, Ozaki, Shintaro, Ryu, Koki, Rzepka, Rafal, Sakaguchi, Keisuke, Sasaki, Shota, Sekine, Satoshi, Suda, Kohei, Sugawara, Saku, Sugiura, Issa, Sugiyama, Hiroaki, Suzuki, Hisami, Suzuki, Jun, Suzumura, Toyotaro, Tachibana, Kensuke, Takagi, Yu, Takami, Kyosuke, Takeda, Koichi, Takeshita, Masashi, Tanaka, Masahiro, Taura, Kenjiro, Tolmachev, Arseny, Ueda, Nobuhiro, Wan, Zhen, Yada, Shuntaro, Yahata, Sakiko, Yamamoto, Yuya, Yamauchi, Yusuke, Yanaka, Hitomi, Yokota, Rio, and Yoshino, Koichiro

Subjects
Computer Science - Computation and Language, Computer Science - Artificial Intelligence
Abstract

This paper introduces LLM-jp, a cross-organizational project for the research and development of Japanese large language models (LLMs). LLM-jp aims to develop open-source and strong Japanese LLMs, and as of this writing, more than 1,500 participants from academia and industry are working together for this purpose. This paper presents the background of the establishment of LLM-jp, summaries of its activities, and technical reports on the LLMs developed by LLM-jp. For the latest activities, visit https://llm-jp.nii.ac.jp/en/.

Published
2024

17. Insights into balloon pulmonary angioplasty and the WHO functional class of chronic thromboembolic pulmonary hypertension patients: findings from the CTEPH AC registry

Author

Ikeda, Nobutaka, Masaki, Kohei, Hosokawa, Kazuya, Funakoshi, Kouta, Taniguchi, Yu, Adachi, Shiro, Inami, Takumi, Yamashita, Jun, Ogino, Hitoshi, Tsujino, Ichizo, Hatano, Masaru, Yaoita, Nobuhiro, Shimokawahara, Hiroto, Tanabe, Nobuhiro, Kubota, Kayoko, Shigeta, Ayako, Ogihara, Yoshito, Horimoto, Koshin, Dohi, Yoshihiro, Kawakami, Takashi, Tamura, Yuichi, Tatsumi, Koichiro, and Abe, Kohtaro

Published
2025
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24. First joint oscillation analysis of Super-Kamiokande atmospheric and T2K accelerator neutrino data

Author

Super-Kamiokande, collaborations, T2K, Abe, S., Abe, K., Akhlaq, N., Akutsu, R., Alarakia-Charles, H., Ali, A., Hakim, Y. I. Alj, Monsalve, S. Alonso, Amanai, S., Andreopoulos, C., Anthony, L. H. V., Antonova, M., Aoki, S., Apte, K. A., Arai, T., Arihara, T., Arimoto, S., Asada, Y., Asaka, R., Ashida, Y., Atkin, E. T., Babu, N., Barbi, M., Barker, G. J., Barr, G., Barrow, D., Bates, P., Batkiewicz-Kwasniak, M., Beauchêne, A., Berardi, V., Berns, L., Bhadra, S., Bhuiyan, N., Bian, J., Blanchet, A., Blondel, A., Bodur, B., Bolognesi, S., Bordoni, S., Boyd, S. B., Bravar, A., Bronner, C., Bubak, A., Avanzini, M. Buizza, Burton, G. T., Caballero, J. A., Calabria, N. F., Cao, S., Carabadjac, D., Carter, A. J., Cartwright, S. L., Casado, M. P., Catanesi, M. G., Cervera, A., Chakrani, J., Chalumeau, A., Chen, S., Cherdack, D., Choi, K., Chong, P. S., Chvirova, A., Cicerchia, M., Coleman, J., Collazuol, G., Cook, L., Cormier, F., Cudd, A., Dalmazzone, C., Daret, T., Dasgupta, P., Davis, C., Davydov, Yu. I., De Roeck, A., De Rosa, G., Dealtry, T., Delogu, C. C., Densham, C., Dergacheva, A., Dharmapal, R., Di Lodovico, F., Lopez, G. Diaz, Dolan, S., Douqa, D., Doyle, T. A., Drapier, O., Duffy, K. E., Dumarchez, J., Dunne, P., Dygnarowicz, K., D'ago, D., Edwards, R., Eguchi, A., Elias, J., Emery-Schrenk, S., Erofeev, G., Ershova, A., Eurin, G., Fannon, J. E. P., Fedorova, D., Fedotov, S., Feltre, M., Feng, J., Feng, L., Ferlewicz, D., Fernandez, P., Finch, A. J., Aguirre, G. A. Fiorentini, Fiorillo, G., Fitton, M. D., Patiño, J. M. Franco, Friend, M., Fujii, Y., Fujisawa, C., Fujita, S., Fukuda, Y., Furui, Y., Gao, J., Gaur, R., Giampaolo, A., Giannessi, L., Giganti, C., Glagolev, V., Goldsack, A., Gonin, M., Rosa, J. González, Goodman, E. A. G., Gorin, A., Gorshanov, K., Gousy-Leblanc, V., Grassi, M., Griskevich, N. J., Guigue, M., Hadley, D., Haigh, J. T., Han, S., Harada, M., Harris, D. A., Hartz, M., Hasegawa, T., Hassani, S., Hastings, N. C., Hayato, Y., Heitkamp, I., Henaff, D., Hill, J., Hino, Y., Hiraide, K., Hogan, M., Holeczek, J., Holin, A., Holvey, T., Van, N. T. Hong, Honjo, T., Horiuchi, S., Hosokawa, K., Hu, Z., Hu, J., Iacob, F., Ichikawa, A. K., Ieki, K., Ikeda, M., Iovine, N., Ishida, T., Ishino, H., Ishitsuka, M., Ishizuka, T., Ito, H., Itow, Y., Izmaylov, A., Izumiyama, S., Jakkapu, M., Jamieson, B., Jang, M. C., Jang, J. S., Jenkins, S. J., Jesús-Valls, C., Ji, J. Y., Jia, M., Jiang, J., Jonsson, P., Joshi, S., Jung, C. K., Jung, S., Kabirnezhad, M., Kaboth, A. C., Kajita, T., Kakuno, H., Kameda, J., Kanemura, Y., Kaneshima, R., Karpova, S., Kasetti, S. P., Kashiwagi, Y., Kasturi, V. S., Kataoka, Y., Katori, T., Kawamura, Y., Kawaue, M., Kearns, E., Khabibullin, M., Khotjantsev, A., Kikawa, T., Kim, S. B., King, S., Kiseeva, V., Kisiel, J., Kneale, L., Kobayashi, H., Kobayashi, T., Kobayashi, M., Koch, L., Kodama, S., Kolupanova, M., Konaka, A., Kormos, L. L., Koshio, Y., Koto, T., Kowalik, K., Kudenko, Y., Kudo, Y., Kuribayashi, S., Kurjata, R., Kurochka, V., Kutter, T., Kuze, M., Kwon, E., La Commara, M., Labarga, L., Lachat, M., Lachner, K., Lagoda, J., Lakshmi, S. M., LamersJames, M., Langella, A., Laporte, J. -F., Last, D., Latham, N., Laveder, M., Lavitola, L., Lawe, M., Learned, J. G., Lee, Y., Lee, S. H., Silverio, D. Leon, Levorato, S., Lewis, S., Li, X., Li, W., Lin, C., Litchfield, R. P., Liu, S. L., Liu, Y. M., Long, K. R., Longhin, A., Moreno, A. Lopez, Lu, X., Ludovici, L., Lux, T., Machado, L. N., Maekawa, Y., Magaletti, L., Mahn, K., Mahtani, K. K., Malek, M., Mandal, M., Manly, S., Marino, A. D., Martens, K., Marti, Ll., Martin, D. G. R., Martin, J. F., Martin, D., Martini, M., Maruyama, T., Matsubara, T., Matsumoto, R., Mattiazzi, M., Matveev, V., Mauger, C., Mavrokoridis, K., Mazzucato, E., McCauley, N., McElwee, J. M., McFarland, K. S., McGrew, C., McKean, J., Mefodiev, A., Megias, G. D., Mehta, P., Mellet, L., Menjo, H., Metelko, C., Mezzetto, M., Migenda, J., Mijakowski, P., Miki, S., Miller, E., Minamino, A., Mine, S., Mineev, O., Mirabito, J., Miura, M., Bueno, L. Molina, Moon, D. H., Mori, M., Moriyama, S., Morrison, P., Muñoz, A., Mueller, Th. A., Munford, D., Munteanu, L., Nagai, Y., Nagai, K., Nakadaira, T., Nakagiri, K., Nakahata, M., Nakajima, Y., Nakamura, A., Nakamura, K., Nakamura, K. D., Nakamura, T., Nakanishi, F., Nakano, Y., Nakaya, T., Nakayama, S., Nakayoshi, K., Naseby, C. E. R., Ngoc, T. V., Nguyen, V. Q., Nguyen, D. T., Nicholson, M., Niewczas, K., Ninomiya, K., Nishijima, K., Nishimori, S., Nishimura, Y., Noguchi, Y., Nosek, T., Nova, F., Novella, P., Nugent, J. C., Odagawa, T., Okazaki, R., Okazawa, H., Okinaga, W., Okumura, K., Okusawa, T., Ommura, Y., Onda, N., Ospina, N., Osu, L., Oyama, Y., O'Flaherty, M., O'Keeffe, H. M., O'Sullivan, L., Périssé, L., Paganini, P., Palladino, V., Paolone, V., Pari, M., Park, R. G., Parlone, J., Pasternak, J., Payne, D., Penn, G. C., de Perio, P., Pershey, D., Pfaff, M., Pickering, L., Pintaudi, G., Pistillo, C., Pointon, B. W., Popov, B., Yrey, A. Portocarrero, Porwit, K., Posiadala-Zezula, M., Prabhu, Y. S., Prasad, H., Pronost, G., Prouse, N. W., Pupilli, F., Quilain, B., Quyen, P. T., Raaf, J. L., Radermacher, T., Radicioni, E., Radics, B., Ramirez, M. A., Ramsden, R. M., Ratoff, P. N., Reh, M., Riccio, C., Richards, B., Rogly, R., Rondio, E., Roth, S., Roy, N., Rubbia, A., Russo, L., Rychter, A., Saenz, W., Sakai, S., Sakashita, K., Samani, S., Santos, A. D., Sato, Y., Sato, K., Schefke, T., Schloesser, C. M., Scholberg, K., Scott, M., Seiya, Y., Sekiguchi, T., Sekiya, H., Seo, J. W., Sgalaberna, D., Shaikhiev, A., Shi, W., Shiba, H., Shibayama, R., Shigeta, N., Shima, S., Shimamura, R., Shimizu, K., Shinoki, M., Shiozawa, M., Shiraishi, Y., Shvartsman, A., Skrobova, N., Skwarczynski, K., Smy, M. B., Smyczek, D., Sobczyk, J. T., Sobel, H. W., Soler, F. J. P., Sonoda, Y., Speers, A. J., Spina, R., Stroke, Y., Suslov, I. A., Suvorov, S., Suzuki, S., Suzuki, A., Suzuki, S. Y., Suzuki, Y., Sánchez, F., Tada, T., Tada, M., Tairafune, S., Takagi, Y., Takeda, A., Takemoto, Y., Takeuchi, Y., Takhistov, V., Takifuji, K., Tanaka, H., Tanaka, H. K., Tanigawa, H., Taniuchi, N., Tano, T., Tarrant, A., Tashiro, T., Teklu, A., Terada, K., Tereshchenko, V. V., Thamm, N., Thiesse, M. D., Thompson, L. F., Toki, W., Tomiya, T., Touramanis, C., Tsui, K. M., Tsukamoto, T., Tzanov, M., Uchida, Y., Vagins, M. R., Vargas, D., Varghese, M., Vasseur, G., Villa, E., Vinning, W. G. S., Virginet, U., Vladisavljevic, T., Wachala, T., Wakabayashi, D., Wallace, H. T., Walsh, J. G., Walter, C. W., Wan, L., Wang, X., Wang, Y., Wark, D., Wascko, M. O., Watanabe, E., Weber, A., Wendell, R. A., Wester, T., Wilking, M. J., Wilkinson, C., Wilson, S. T., Wilson, J. R., Wood, K., Wret, C., Wu, Y., Xia, J., Xie, Z., Xu, B. D., Xu, Y. -H., Yamamoto, K., Yamamoto, T., Yamauchi, K., Yanagisawa, C., Yang, G., Yang, B. S., Yang, J. Y., Yankelevich, A., Yano, T., Yasutome, K., Yershov, N., Yevarouskaya, U., Yokoyama, M., Yoo, J., Yoshida, T., Yoshida, S., Yoshimoto, Y., Yoshimura, N., Yoshioka, Y., Yu, M., Yu, I., Zaki, R., Zaldivar, B., Zalewska, A., Zalipska, J., Zaremba, K., Zarnecki, G., Zhang, J., Zhang, A. Q., Zhang, B., Zhao, X. Y., Zhong, H., Zhu, T., Ziembicki, M., Zimmerman, E. D., Zito, M., and Zsoldos, S.

Subjects
High Energy Physics - Experiment
Abstract

The Super-Kamiokande and T2K collaborations present a joint measurement of neutrino oscillation parameters from their atmospheric and beam neutrino data. It uses a common interaction model for events overlapping in neutrino energy and correlated detector systematic uncertainties between the two datasets, which are found to be compatible. Using 3244.4 days of atmospheric data and a beam exposure of $19.7(16.3) \times 10^{20}$ protons on target in (anti)neutrino mode, the analysis finds a 1.9$\sigma$ exclusion of CP-conservation (defined as $J_{CP}=0$) and a preference for the normal mass ordering., Comment: 12 pages, 4 figures

Published
2024

25. Theory of the inverse Rashba-Edelstein effect induced by thermal spin injection

Author

Hosokawa, Kaiji, Yama, Masaki, Matsuo, Mamoru, and Kato, Takeo

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We theoretically consider a junction composed of a ferromagnetic insulator (FI) and a two-dimensional electron gas (2DEG) with Rashba- and Dresselhaus-type spin-orbit interactions. Using the Boltzmann equation, we calculate an electric current in 2DEG induced by the inverse Rashba-Edelstein effect when imposing the temperature difference between FI and 2DEG. We clarify how the induced current depends on the magnetization direction of FI, spin texture on the Fermi surface of 2DEG, and temperature. Our result provides an important foundation for an accurate analysis of the inverse Rashba-Edelstein effect induced by thermal spin injection., Comment: 14 pages, 3 figures

Published
2024
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26. Combined Pre-Supernova Alert System with Kamland and Super-Kamiokande

Author

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

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

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

Published
2024
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27. Development of a data overflow protection system for Super-Kamiokande to maximize data from nearby supernovae

Author

Mori, M., Abe, K., 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., Nakano, Y., Nakahata, M., Nakayama, S., Noguchi, Y., Okamoto, K., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Perisse, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Edwards, R., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Bronner, C., Feng, J., Hu, J. R., Hu, Z., Kawaune, M., Kikawa, T., LiCheng, F., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Lakshmi, S. M., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Wilking, M. J., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Kitagawa, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Martens, K., Tsui, K. M., Vagins, M. R., Valls, C. J., Xia, J., Kuze, M., Izumiyama, S., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Yoshida, T., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Hadley, D., Nicholson, M., Flaherty, M. O', Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.

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

Neutrinos from very nearby supernovae, such as Betelgeuse, are expected to generate more than ten million events over 10\,s in Super-Kamokande (SK). At such large event rates, the buffers of the SK analog-to-digital conversion board (QBEE) will overflow, causing random loss of data that is critical for understanding the dynamics of the supernova explosion mechanism. In order to solve this problem, two new DAQ modules were developed to aid in the observation of very nearby supernovae. The first of these, the SN module, is designed to save only the number of hit PMTs during a supernova burst and the second, the Veto module, prescales the high rate neutrino events to prevent the QBEE from overflowing based on information from the SN module. In the event of a very nearby supernova, these modules allow SK to reconstruct the time evolution of the neutrino event rate from beginning to end using both QBEE and SN module data. This paper presents the development and testing of these modules together with an analysis of supernova-like data generated with a flashing laser diode. We demonstrate that the Veto module successfully prevents DAQ overflows for Betelgeuse-like supernovae as well as the long-term stability of the new modules. During normal running the Veto module is found to issue DAQ vetos a few times per month resulting in a total dead time less than 1\,ms, and does not influence ordinary operations. Additionally, using simulation data we find that supernovae closer than 800~pc will trigger Veto module resulting in a prescaling of the observed neutrino data., Comment: 28 pages, 18 figures. Submitted to PTEP

Published
2024
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28. Metallicity dependence of dust growth in a protoplanetary disk

Author

Matsukoba, Ryoki, Vorobyov, Eduard I., and Hosokawa, Takashi

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

In the context of planet formation, growth from micron-sized grains to kilometer-sized planetesimals is a crucial question. Since the dust growth rate depends on the amount of dust, realizing planet formation scenarios based on dust growth is challenging in environments with low metallicity, i.e. less dust. We investigate dust growth during disk evolution, particularly focusing on the relationship with metallicity. We perform two-dimensional thin-disk hydrodynamic simulations to track the disk evolution over 300 kyr from its formation. The dust motion is solved separately from the gas motion, with its distribution changing due to drag forces from the gas. Dust size growth is also accounted for, with the magnitude of the drag force varying according to the dust size. We employ three models with metallicities of 1.0, 0.1, and 0.01 ${\rm Z}_{\odot}$, i.e. dust-to-gas mass ratios of 10$^{-2}$, 10$^{-3}$, and 10$^{-4}$, respectively. In the disks with the metallicities $\ge0.1$ ${\rm Z}_{\odot}$, the dust radii reach cm sizes, consistent with estimations from the dust growth timescale. Conversely, for the metallicity of 0.01 ${\rm Z}_{\odot}$, the maximum dust size is only 10$^{-2}$ cm, with almost no growth observed across the entire disk scale ($\sim$100 au). At the metallicities $\ge0.1$ ${\rm Z}_{\odot}$, the decoupling between grown dust and gas leads to non-uniform dust-to-gas mass ratios. However, deviations from the canonical value of this ratio have no impact on the gravitational instability of the disk. The formation of dust rings is confirmed in the innermost part of the disk ($\sim$10--30 au). The dust rings where the dust-to-gas mass ratio is enhanced, and the Stokes number reaches $\sim$0.1, are suitable environments for the streaming instability. We conjecture that planetesimal formation occurs through the streaming instability in these dust rings., Comment: 13 pages, 12 figures, submitted to A&A

Published
2024

29. Measurements of the charge ratio and polarization of cosmic-ray muons with the Super-Kamiokande detector

Author

Kitagawa, H., Tada, T., 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., Nakano, Y., Nakahata, M., Nakayama, S., Noguchi, Y., Okamoto, K., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchêne, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Calabria, N. F., Catanesi, M. G., Radicioni, E., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Périssé, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesús-Valls, C., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Terada, K., Ishitsuka, M., Ito, H., Kinoshita, T., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Yoshida, T., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.

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

We present the results of the charge ratio ($R$) and polarization ($P^{\mu}_{0}$) measurements using the decay electron events collected from 2008 September to 2022 June by the Super-Kamiokande detector. Because of its underground location and long operation, we performed high precision measurements by accumulating cosmic-ray muons. We measured the muon charge ratio to be $R=1.32 \pm 0.02$ $(\mathrm{stat.}{+}\mathrm{syst.})$ at $E_{\mu}\cos \theta_{\mathrm{Zenith}}=0.7^{+0.3}_{-0.2}$ $\mathrm{TeV}$, where $E_{\mu}$ is the muon energy and $\theta_{\mathrm{Zenith}}$ is the zenith angle of incoming cosmic-ray muons. This result is consistent with the Honda flux model while this suggests a tension with the $\pi K$ model of $1.9\sigma$. We also measured the muon polarization at the production location to be $P^{\mu}_{0}=0.52 \pm 0.02$ $(\mathrm{stat.}{+}\mathrm{syst.})$ at the muon momentum of $0.9^{+0.6}_{-0.1}$ $\mathrm{TeV}/c$ at the surface of the mountain; this also suggests a tension with the Honda flux model of $1.5\sigma$. This is the most precise measurement ever to experimentally determine the cosmic-ray muon polarization near $1~\mathrm{TeV}/c$. These measurement results are useful to improve the atmospheric neutrino simulations., Comment: 29 pages, 45 figures

Published
2024
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30. Second gadolinium loading to Super-Kamiokande

Author

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., Nakano, Y., Nakahata, M., 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., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Uchida, Y., Berardi, V., Calabria, N. F., Catanesi, M. G., Radicioni, E., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Mattiazzi, M., Ludovici, L., Gonin, M., Perisse, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Shi, W., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesus-Valls, C., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Terada, K., Ishitsuka, M., Ito, H., Ommura, Y., Shigeta, N., Shinoki, M., Yamauchi, K., Yoshida, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., Suzuki, S., Scovell, P. R., Meehan, E., Bandac, I., Pena-Garay, C., Perez, J., Gileva, O., Lee, E. K., Leonard, D. S., Sakakieda, Y., Sakaguchi, A., Sueki, K., Takaku, Y., and Yamasaki, S.

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

The first loading of gadolinium (Gd) into Super-Kamiokande in 2020 was successful, and the neutron capture efficiency on Gd reached 50\%. To further increase the Gd neutron capture efficiency to 75\%, 26.1 tons of $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ was additionally loaded into Super-Kamiokande (SK) from May 31 to July 4, 2022. As the amount of loaded $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ was doubled compared to the first loading, the capacity of the powder dissolving system was doubled. We also developed new batches of gadolinium sulfate with even further reduced radioactive impurities. In addition, a more efficient screening method was devised and implemented to evaluate these new batches of $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$. Following the second loading, the Gd concentration in SK was measured to be $333.5\pm2.5$ ppm via an Atomic Absorption Spectrometer (AAS). From the mean neutron capture time constant of neutrons from an Am/Be calibration source, the Gd concentration was independently measured to be 332.7 $\pm$ 6.8(sys.) $\pm$ 1.1(stat.) ppm, consistent with the AAS result. Furthermore, during the loading the Gd concentration was monitored continually using the capture time constant of each spallation neutron produced by cosmic-ray muons,and the final neutron capture efficiency was shown to become 1.5 times higher than that of the first loaded phase, as expected., Comment: 34 pages, 13 figures, submitted to Nuclear Inst. and Methods in Physics Research, A

Published
2024
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31. Performance of SK-Gd's Upgraded Real-time Supernova Monitoring System

Author

Kashiwagi, Y., Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, K., Ieki, K., Ikeda, M., Kameda, J., Kanemura, Y., Kaneshima, R., Kataoka, Y., Miki, S., Mine, S., Miura, M., Moriyama, S., Nakano, Y., Nakahata, M., 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., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointn, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchêne, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Mattiazzi, M., Ludovici, L., Gonin, M., Périssé, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Lakshmi, S. M., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Wilking, M. J., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesús-Valls, C., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Kuze, M., Izumiyama, S., Matsumoto, R., Ishitsuka, M., Ito, H., Ommura, Y., Shigeta, N., Shinoki, M., Yamauchi, K., Yoshida, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., and Suzuki, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Among multi-messenger observations of the next galactic core-collapse supernova, Super-Kamiokande (SK) plays a critical role in detecting the emitted supernova neutrinos, determining the direction to the supernova (SN), and notifying the astronomical community of these observations in advance of the optical signal. On 2022, SK has increased the gadolinium dissolved in its water target (SK-Gd) and has achieved a Gd concentration of 0.033%, resulting in enhanced neutron detection capability, which in turn enables more accurate determination of the supernova direction. Accordingly, SK-Gd's real-time supernova monitoring system (Abe te al. 2016b) has been upgraded. SK_SN Notice, a warning system that works together with this monitoring system, was released on December 13, 2021, and is available through GCN Notices (Barthelmy et al. 2000). When the monitoring system detects an SN-like burst of events, SK_SN Notice will automatically distribute an alarm with the reconstructed direction to the supernova candidate within a few minutes. In this paper, we present a systematic study of SK-Gd's response to a simulated galactic SN. Assuming a supernova situated at 10 kpc, neutrino fluxes from six supernova models are used to characterize SK-Gd's pointing accuracy using the same tools as the online monitoring system. The pointing accuracy is found to vary from 3-7$^\circ$ depending on the models. However, if the supernova is closer than 10 kpc, SK_SN Notice can issue an alarm with three-degree accuracy, which will benefit follow-up observations by optical telescopes with large fields of view., Comment: 38 pages, 29 figures, 6 tables

Published
2024

32. 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

34. Efficacy of liposomal irinotecan + 5-FU/LV vs. S-1 in gemcitabine-refractory metastatic pancreatic cancer: a real-world study using inverse probability of treatment weighting

Author

Imaoka, Hiroshi, Ikeda, Masafumi, Kobayashi, Satoshi, Ohba, Akihiro, Ueno, Masayuki, Suzuki, Yuko, Tsumura, Hidetaka, Kimura, Nana, Kawaguchi, Shinya, Kawamoto, Yasuyuki, Nakachi, Kohei, Tsuji, Kunihiro, Kobayashi, Noritoshi, Ashida, Reiko, Okano, Naohiro, Umemoto, Kumiko, Murohisa, Gou, Hosokawa, Ayumu, Asagi, Akinori, Nebiki, Hiroko, Suzuki, Rei, Terashima, Takeshi, Shibata, Ryusuke, Kawata, Kazuhito, Doi, Toshifumi, Ohyama, Hiroshi, Kitano, Yohei, Shioji, Kazuhiko, Okuyama, Hiroyuki, Naganuma, Atsushi, Negoro, Yuji, Sakamoto, Yasunari, Shimizu, Satoshi, Morizane, Chigusa, Ueno, Makoto, Furuse, Junji, and Nagano, Hiroaki

Published
2024
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38. Comparative Effectiveness of Patient-Driven versus Standardized Diabetes Shared Medical Appointments: A Pragmatic Cluster Randomized Trial

Author

Kwan, Bethany M., Dickinson, L. Miriam, Dailey-Vail, Jennifer, Glasgow, Russell E., Gritz, R. Mark, Gurfinkel, Dennis, Hester, Christina M., Holtrop, Jodi Summers, Hosokawa, Patrick, Lanigan, Angela, Nease, Jr, Donald E., Nederveld, Andrea, Phimphasone-Brady, Phoutdavone, Ritchie, Natalie D., Sajatovic, Martha, Wearner, Robyn, Begum, Anowara, Carter, Madelaine, Carrigan, Thomas, Clay, Barbara, Downey, David, Koren, Ramona, Trujillo, Sharon A., and Waxmonsky, Jeanette A.

Published
2024
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43. First Study of the PIKACHU Project: Development and Evaluation of High-Purity Gd$_3$Ga$_3$Al$_2$O$_{12}$:Ce Crystals for $^{160}$Gd Double Beta Decay Search

Author

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

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

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

Published
2024

44. Gas Dynamical Friction on Accreting Objects

Author

Suzuguchi, Tomoya, Sugimura, Kazuyuki, Hosokawa, Takashi, and Matsumoto, Tomoaki

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The drag force experienced by astronomical objects moving through gaseous media (gas dynamical friction) plays a crucial role in their orbital evolution. Ostriker (1999) derived a formula for gas dynamical friction by linear analysis, and its validity has been confirmed through subsequent numerical simulations. However, the effect of gas accretion onto the objects on the dynamical friction is yet to be understood. In this study, we investigate the Mach number dependence of dynamical friction considering gas accretion through three-dimensional nested-grid simulations. We find that the net frictional force, determined by the sum of the gravitational force exerted by surrounding gas and momentum flux transferred by accreting gas, is independent of the resolution of simulations. Only the gas outside the Bondi-Hoyle-Lyttleton radius contributes to dynamical friction, because the gas inside this radius is eventually absorbed by the central object and returns the momentum obtained through the gravitational interaction with it. In the subsonic case, the front-back asymmetry induced by gas accretion leads to larger dynamical friction than predicted by the linear theory. Conversely, in the slightly supersonic case with the Mach number between 1 and 1.5, the nonlinear effect leads to a modification of the density distribution in a way reducing the dynamical friction compared with the linear theory. At a higher Mach number, the modification becomes insignificant and the dynamical friction can be estimated with the linear theory. We also provide a fitting formula for dynamical friction based on our simulations, which can be used in a variety of applications., Comment: 16 pages, 12 figures, 1 Tabel. Accepted for publication in ApJ

Published
2024

45. Impact of radiative feedback on the initial mass function of metal-poor stars

Author

Chon, Sunmyon, Hosokawa, Takashi, Omukai, Kazuyuki, and Schneider, Raffaella

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract

The stellar initial mass function (IMF) in the early universe is essential to understand the formation of ancient galaxies. To this end, we conduct a series of long-term radiation hydrodynamic simulations following star cluster formation, varying the metallicity from $Z/Z_\odot = 10^{-4}$ to $1$. We particularly consider the effects of protostellar radiative feedback, which modify the exact shape of the IMF and determine the star formation efficiency (SFE), i.e. the ratio between the mass in stars and the initial gas mass in the parental cloud. Our results show that the IMF changes from a Salpeter-type to a top-heavy function as the metallicity decreases. When $Z/Z_\odot \lesssim 10^{-2}$, the IMF becomes log-flat and distinct from a Salpeter-like IMF. Stellar feedback is effective in shaping both the low- and high-mass ends of the IMF. Heating of dust grains by stellar radiation suppresses small-scale fragmentation and reduces the number of low-mass stars with $M_* \lesssim 1~M_\odot$ at all metallicities. The ionizing radiation hinders the growth of massive stars, steepening the slope of the IMF at the high-mass end. The resulting feedback is more effective at lower metallicity, and star formation is regulated by stellar radiative feedback, with the SFE decreasing with decreasing metallicity. We suggest that the unexpectedly large number of UV-bright galaxies at $z>10$ reported by JWST observations can be explained by considering star cluster formation at $Z/Z_\odot \sim 10^{-2}$ or $10^{-3}$, where the IMF is top-heavy, but the SFE is not too low due to stellar feedback., Comment: 22 pages, 19 figures, submitted to MNRAS

Published
2023

46. Performance of the Fully-equipped Spin Flip Chopper For Neutron Lifetime Experiment at J-PARC

Author

Mishima, K., Ichikawa, G., Fuwa, Y., Hasegawa, T., Hino, M., Hosokawa, R., Ino, T., Iwashita, Y., Kitaguchi, M., Matsuzaki, S., Mogi, T., Okabe, H., Oku, T., Okudaira, T., Seki, Y., Shimizu, H. E., Shimizu, H. M., Takahashi, S., Tanida, M., Yamashita, S., Yokohashi, M., and Yoshioka, T.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

To solve the ''neutron lifetime puzzle,'' where measured neutron lifetimes differ depending on the measurement methods, an experiment with pulsed neutron beam at J-PARC is in progress. In this experiment, neutrons are bunched into 40-cm lengths using a spin flip chopper (SFC), where the statistical sensitivity was limited by the aperture size of the SFC. The SFC comprises three sets of magnetic supermirrors and two resonant spin flippers. In this paper, we discuss an upgrade to enlarge the apertures of the SFC. With this upgrade, the statistics per unit time of the neutron lifetime experiment increased by a factor of 2.8, while maintaining a signal-to-noise ratio of 250-400 comparable to the previous one. Consequently, the time required to reach a precision of 1 s in the neutron lifetime experiment was reduced from 590 to 170 days, which is a significant reduction in time. This improvement in statistic will also contribute to the reduction of systematic uncertainties, such as background evaluation, fostering further advancements in the neutron lifetime experiments at J-PARC., Comment: 33 pages, 22 figures

Published
2023

47. Solar neutrino measurements using the full data period of Super-Kamiokande-IV

Author

Collaboration, Super-Kamiokande, Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, K., Ieki, K., Ikeda, M., Imaizumi, S., Iyogi, K., Kameda, J., Kanemura, Y., Kaneshima, R., Kashiwagi, Y., Kataoka, Y., Kato, Y., Kishimoto, Y., Miki, S., Mine, S., Miura, M., Mochizuki, T., Moriyama, S., Nagao, Y., Nakahata, M., Nakano, Y., Nakayama, S., Noguchi, Y., Okada, T., Okamoto, K., Orii, A., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, R., Wang, X., Yoshida, S., Bravo-Berguno, D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Blaszczyk, F. d. M., Kachulis, C., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Yankelevich, A., Ganezer, K. S., Hill, J., Jang, M. C., Kim, J. Y., Lee, S., Lim, I. T., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Imber, J., Mueller, Th. A., Paganini, P., Rogly, R., Quilain, B., Santos, A., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Matsuno, S., Iovine, N., Choi, K., Cao, S., Anthony, L. H. V., Litchfield, R. P., Prouse, N., Marin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Intonti, R. A., Radicioni, E., Calabria, N. F., De Rosa, G., Langella, A., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Perisse, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Friend, M., Hasegawa, T., Ishida, T., Jakkapu, M., Kobayashi, T., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Boschi, T., Bhuiyan, N., Burton, G. T., Gao, J., Goldsack, A., Katori, T., Di Lodovico, F., Migenda, J., Sedgwick, S. Molina, Ramsden, R. M., Taani, M., Xie, Z., Zsoldos, S., Abe, KE., Hasegawa, M., Isobe, Y., Kotsar, Y., Miyabe, H., Ozaki, H., Shiozawa, T., Sugimoto, T., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Yamamoto, S., Zhong, H., Ashida, Y., Feng, J., Feng, L., Hayashino, T., Hirota, S., Hu, J. R., Hu, Z., Jiang, M., Kawaue, M., Kikawa, T., Mori, M., Nakamura, KE., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Pritchard, A., Tarrant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Murase, M., Ninomiya, K., Niwa, T., Tsukada, M., Yoshioka, Y., Frankiewicz, K., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jiang, J., Jia, M., Jung, C. K., Palomino, J. L., Santucci, G., Shi, W., Vilela, C., Yanagisawa, C., Fukuda, D., Hagiwara, K., Harada, M., Hino, Y., Horai, T., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Nakanishi, F., Piplani, N., Sakai, S., Sakuda, M., Tada, T., Tano, T., Xu, C., Yamaguchi, R., Ishizuka, T., Kuno, Y., Barr, G., Barrow, D., Cook, L., Samani, S., Simpson, C., Wark, D., Holin, A. M., Nova, F., Jung, S., Yang, B., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Choi, Y., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Tairahune, S., Nishijima, K., Eguchi, A., Iwamoto, K., Nakagiri, K., Nakajima, Y., Ogawa, N., Shima, S., Watanabe, E., Yokoyama, M., Calland, R. G., Fujita, S., Jesus-Valls, C., Junjie, X., Ming, T. K., de Perio, P., Martens, K., Murdoch, M., Vagins, M. R., Izumiyama, S., Kuze, M., Matsumoto, R., Okajima, Y., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Ohta, K., Ommura, Y., Shinoki, M., Shigeta, N., Suganuma, T., Yamaguchi, K., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Berkman, S., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Walker, J., Amanai, S., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Sasaki, R., Suzuki, S., and Wada, K.

Subjects
High Energy Physics - Experiment
Abstract

An analysis of solar neutrino data from the fourth phase of Super-Kamiokande~(SK-IV) from October 2008 to May 2018 is performed and the results are presented. The observation time of the data set of SK-IV corresponds to $2970$~days and the total live time for all four phases is $5805$~days. For more precise solar neutrino measurements, several improvements are applied in this analysis: lowering the data acquisition threshold in May 2015, further reduction of the spallation background using neutron clustering events, precise energy reconstruction considering the time variation of the PMT gain. The observed number of solar neutrino events in $3.49$--$19.49$ MeV electron kinetic energy region during SK-IV is $65,443^{+390}_{-388}\,(\mathrm{stat.})\pm 925\,(\mathrm{syst.})$ events. Corresponding $\mathrm{^{8}B}$ solar neutrino flux is $(2.314 \pm 0.014\, \rm{(stat.)} \pm 0.040 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}$, assuming a pure electron-neutrino flavor component without neutrino oscillations. The flux combined with all SK phases up to SK-IV is $(2.336 \pm 0.011\, \rm{(stat.)} \pm 0.043 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}$. Based on the neutrino oscillation analysis from all solar experiments, including the SK $5805$~days data set, the best-fit neutrino oscillation parameters are $\rm{sin^{2} \theta_{12,\,solar}} = 0.306 \pm 0.013 $ and $\Delta m^{2}_{21,\,\mathrm{solar}} = (6.10^{+ 0.95}_{-0.81}) \times 10^{-5}~\rm{eV}^{2}$, with a deviation of about 1.5$\sigma$ from the $\Delta m^{2}_{21}$ parameter obtained by KamLAND. The best-fit neutrino oscillation parameters obtained from all solar experiments and KamLAND are $\sin^{2} \theta_{12,\,\mathrm{global}} = 0.307 \pm 0.012 $ and $\Delta m^{2}_{21,\,\mathrm{global}} = (7.50^{+ 0.19}_{-0.18}) \times 10^{-5}~\rm{eV}^{2}$., Comment: 47 pages, 61 figures

Published
2023
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