Article
Physics, Multidisciplinary
Jameel-Un Nabi, Necla Cakmak, Asim Ullah, Asad Ullah Khan
Summary: This paper investigates the beta-decay properties of nuclei with neutron number N = 126 using two different models to calculate decay rates and half-lives, considering Gamow-Teller and first-forbidden transitions. The inclusion of first-forbidden contributions led to better agreement with measured half-lives, suggesting a significant decrement in calculated half-lives of isotones. The possible implications of waiting point nuclei on r-process nucleosynthesis are briefly discussed.
Article
Astronomy & Astrophysics
Long Zhu
Summary: The study quantitatively evaluated the impact of relative shell inhibition on the production cross sections of N=126 isotones for the first time, indicating that combinations characterized by double closed shell structure are unfavorable for producing unknown N=126 isotones. The effects of shell structure on production cross sections are mainly from the de-excitation process.
Article
Astronomy & Astrophysics
O. Hall, T. Davinson, A. Estrade, J. Liu, G. Lorusso, F. Montes, S. Nishimura, V. H. Phong, P. J. Woods, J. Agramunti, D. S. Ahn, A. Algora, J. M. Allmond, H. Baba, S. Bae, N. T. Brewer, C. G. Bruno, R. Caballero-Folch, F. Calvino, P. J. Coleman-Smith, G. Cortes, I. Dillmann, C. Domingo-Pardo, A. Fijalkowska, N. Fukuda, S. Go, C. J. Griffin, R. Grzywacz, J. Ha, L. J. Harkness-Brennan, T. Isobe, D. Kahl, L. H. Khiem, G. G. Kiss, A. Korgul, S. Kubono, M. Labiche, I. Lazarus, J. Liang, Z. Liu, K. Matsui, K. Miernik, B. Moon, A. I. Morales, P. Morrall, M. R. Mumpower, N. Nepal, R. D. Page, M. Piersa, V. F. E. Pucknell, B. C. Rasco, B. Rubio, K. P. Rykaczewski, H. Sakurai, Y. Shimizu, D. W. Stracener, T. Sumikama, H. Suzuki, J. L. Tain, H. Takeda, A. Tarifeno-Saldivia, A. Tolosa-Delgado, M. Wolinska-Cichocka, R. Yokoyama
Summary: Theoretical models of beta-delayed neutron emission are crucial for r-process calculations, but lack of experimental data makes benchmarking predictions challenging. This study presents beta-delayed neutron emission probabilities for 33 nuclides, 16 for the first time, affecting final abundance distribution in the second r-process peak. Measurements were performed at RIKEN using advanced detectors, constraining theoretical model predictions in the region.
Article
Physics, Multidisciplinary
Nguyen Duy Ly, Nguyen Ngoc Duy, Nguyen Kim Uyen, Vinh N T Pham
Summary: The study found overlapping conditions for N = 50, 82, and 126 isotopes to be waiting points in the r-process, but differences in conditions due to uncertainties in nuclear masses affecting the appearance of all three peaks simultaneously. The discrepancies in conditions based on different models highlight the importance of accurate measurements in understanding r-process evolution.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2021)
Article
Physics, Nuclear
Bharti Bhoy, Praveen C. Srivastava
Summary: In this study, we systematically investigated the properties of N=82 and N=126 isotones using the shell model. We compared the similarities between these two isotonic chains based on the resemblance of high-j orbitals. In addition to nuclear spectroscopic properties, we also discussed the characteristics of different isomeric states in these regions.
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS
(2022)
Article
Physics, Nuclear
C. F. Persch, P. A. DeYoung, S. Lyons, A. Spyrou, S. N. Liddick, F. Naqvi, B. P. Crider, A. C. Dombos, J. Gombas, D. L. Bleuel, B. A. Brown, A. Couture, L. Crespo Campo, J. Engel, M. Guttormsen, A. C. Larsen, R. Lewis, S. Karampagia, S. Mosby, E. M. Ney, A. Palmisano, G. Perdikakis, C. J. Prokop, T. Renstrom, S. Siem, M. K. Smith, S. J. Quinn
Summary: This paper presents the P-decay feeding intensity distribution and Gamow-Teller transition strength distribution of Ni-71,73, measured using total absorption spectroscopy. The experimental results provide sensitive constraints for theoretical models and aid in future r-process studies in astrophysics.
Article
Astronomy & Astrophysics
Sanjana Curtis, Philipp Mosta, Zhenyu Wu, David Radice, Luke Roberts, Giacomo Ricigliano, Albino Perego
Summary: In this study, we investigate r-process nucleosynthesis and kilonova emission resulting from binary neutron star mergers. We find that the wind from hypermassive neutron star remnants may be the dominant component producing the kilonova emission.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Zhendong An, Weiwei Qiu, Wei Jiang, Gaole Yang, Xiankai Li, Zhengfa Liao, Ziyue Zhuang, Xiaoping Zhang, Shengli Chen, Chenchen Guo, Erxi Xiao, Xiao Fang, Xinxiang Li, Hongwei Wang, Xinrong Hu, Bing Jiang, Wenqing Shen, Jincheng Wang, Jie Ren, Xichao Ruan, Dexin Wang, Su-Yalatu Zhang, Wen Luo, Zhichao Zhu, Haoyang Lan, Zongwei Cao, Xu Ma, Yingdu Liu, Pusen Wang, Yi Yang, Ping Su, Xiangai Deng, Wanbing He, Yugang Ma, Chunwang Ma, Yuting Wang, Pengqin He, Renguang Tang, Tao Zhou, Jing Wang, Han Yi, Yue Zhang, Yonghao Chen, Ruirui Fan, Keqing Gao, Qiang Li, Kang Sun, Zhixin Tan, Minhao Gu, Hantao Jing, Jingyu Tang
Summary: The neutron capture cross section of Ta-181 was measured using the time-of-flight technique and liquid scintillator detectors at the backstreaming white neutron facility (Back-n) of China spallation neutron source (CSNS). The MACS value of Ta-181 at stellar s-process temperatures shows a significant discrepancy with the recommended value.
SCIENTIFIC REPORTS
(2023)
Article
Physics, Nuclear
G. X. Dong, X. B. Wang, N. Michel, M. Plosajczak
Summary: This study investigates the properties of Li-9 and the reaction cross section Li-8(n, gamma)Li-9 using the GSM-CC model. The results suggest that this reaction does not significantly impact heavy-element production and is primarily driven by direct E1 transition to the ground state of Li-8.
Article
Multidisciplinary Sciences
Yi-Xing Wang, Yi-Yuan Cheng, Thomas T. S. Kuo
Summary: In this paper, the yrast states of Po-210 and Rn-212 isotones with N=126 are studied using the nucleon-pair approximation and particle-hole excitations, with a low-momentum interaction Vlow-k renormalized from the free CD-Bonn NN potential. The results show a good agreement with experimental level structures, B(E2)s, and B(E3)s. The probabilities of neutron particle-hole excitations in the yrast states are also calculated, with a focus on negative-parity states and their configurations across the N=126 shell gap.
Article
Physics, Nuclear
J. Wisniewski, W. Urban, T. Rzaca-Urban, K. Sieja, A. Blanc, M. Jentschel, C. Micheagnoli, P. Mutti, U. Koester, G. de France, G. S. Simpson, C. A. Ur
Summary: Excited levels in 92Kr, 96Zr, and 98Mo nuclei were studied using high-statistics multiple-γ coincidence data. New levels, especially with low spins, were searched for and spin-parity assignments to known levels were confirmed. The experimental results were compared with large-scale shell-model calculations to understand the microscopic structure of these nuclei.
Article
Physics, Nuclear
S. Zhang, G. Li, W. Jiang, D. X. Wang, J. Ren, M. Huang, E. T. Li, J. Y. Tang, X. C. Ruan, H. W. Wang, Z. H. Li, Y. S. Chen, L. X. Liu, X. X. Li, Q. W. Fan, R. R. Fan, X. R. Hu, J. C. Wang, X. Li, D. D. Niu, N. Song, M. Gu
Summary: The (n, gamma) cross section data for 159Tb was measured using the C6D6 detector system at the China spallation neutron source. The derived Maxwellian-averaged cross sections (MACS), based on the measured data, are in good agreement with KADoNiS-v0.3 and JEFF-3.3, but over-estimate significantly in KADoNiS-v1.0 and ENDF-VIII.0. The stellar evolution simulation using the obtained rate of 159Tb(n, gamma) 160Tb shows significant changes in abundances around A approximate to 160 compared to ENDF/B-VIII.0.
Article
Astronomy & Astrophysics
Vladimir N. Kondratyev
Summary: In high magnetic induction levels relevant to core-collapse supernovae and neutron star mergers, nuclear reactions exhibit a linear magnetic response due to the Zeeman effect. Neutron component increases linearly with shell angular momentum, while proton contribution grows quadratically. Magnetic effects lead to a shift of the r-process path towards smaller mass numbers and an increase in the volume of low-mass nuclides in peaks of the r-process nuclei.
Article
Physics, Nuclear
C. Ma, Y. Lu, Y. Lei, Y. M. Zhao
Summary: In this paper, we systematically calculate the n-decay half-lives of waiting-point isotones with N = 81 and 82 in the r-process using the nucleon-pair approximation. A phenomenological form of the Hamiltonian, including single-particle energies, pairing plus quadrupole interactions, and Gamow-Teller interactions, is assumed. Theoretical n-decay energies are derived based on Bayesian machine learning, and a good agreement with experimental values is achieved by using the nucleon-pair truncated model space dominated by S-pair condensation.
Article
Physics, Nuclear
Mengke Li, Bradley S. Meyer
Summary: This passage discusses the nuclear evolution and abundance pattern formation during r-process expansions. The isotopic abundances in equilibrium are approximated as Gaussians, and are influenced by nuclear pairing and shell effects. Understanding these details is crucial for studying r-process nucleosynthesis.
Article
Astronomy & Astrophysics
Ataru Tanikawa, Takashi Yoshida, Tomoya Kinugawa, Koh Takahashi, Hideyuki Umeda
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
Ataru Tanikawa, Hajime Susa, Takashi Yoshida, Alessandro A. Trani, Tomoya Kinugawa
Summary: The study presents the merger rate density of Population III binary black holes, revealing that mergers with high-mass black holes may dominate in the future. The effective spins of these mergers are low and the number ratio of different types of mergers varies.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Ataru Tanikawa, Tomoya Kinugawa, Takashi Yoshida, Kotaro Hijikawa, Hideyuki Umeda
Summary: The study highlights the importance of binary population synthesis calculations in Pop III environments for the formation of GW190521-like BH-BH systems. The formation of GW190521-like BH-BHs is strongly influenced by convective overshooting in stellar evolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Chris Nagele, Hideyuki Umeda, Koh Takahashi, Takashi Yoshida, Kohsuke Sumiyoshi
Summary: The study calculated the neutrino signal generated by the collapse of Population III supermassive stars using a newly developed neutrino transfer code. It was found that in the SMS models with a mass range around 10^4 solar masses, the neutrino sphere has a larger radius and lower density, with neutrino luminosity significantly lower than previous analytical models. The possibility of detecting a neutrino burst from an SMS or the neutrino background from many SMSs was discussed, with conclusions suggesting low likelihood of detection under current technology.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Takashi Yoshida, Tomoya Takiwaki, David R. Aguilera-Dena, Kei Kotake, Koh Takahashi, Ko Nakamura, Hideyuki Umeda, Norbert Langer
Summary: A 3D hydrodynamics simulation was conducted for the evolution of the oxygen shell of a fast-rotating massive star, revealing the presence of spiral arm structures in the equatorial plane of the Si/O shell, which might affect the explosion or implosion of the star.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Kotaro Hijikawa, Ataru Tanikawa, Tomoya Kinugawa, Takashi Yoshida, Hideyuki Umeda
Summary: The study reveals that in the presence of very massive third-generation stars, binary black hole mergers can reach a maximum mass of 686 solar masses, with low effective inspiral spin. No conclusive detection of mergers beyond the mass gap has been made so far, and future gravitational wave detectors are expected to observe more merger events.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Ataru Tanikawa, Takashi Yoshida, Tomoya Kinugawa, Alessandro A. Trani, Takashi Hosokawa, Hajime Susa, Kazuyuki Omukai
Summary: We investigate the formation of merging binary black holes through isolated binary evolution and find that the predicted merger rate density and primary black hole mass distribution are consistent with gravitational wave observations. Population III and EMP binary stars play a significant role in pair instability mass gap events, with the number of events increasing with redshift.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Dai Tateishi, Satoru Katsuda, Yukikatsu Terada, Fabio Acero, Takashi Yoshida, Shin-ichiro Fujimoto, Hidetoshi Sano
Summary: This study reports the discovery of an X-ray emitting circumstellar material knot inside the synchrotron dominant supernova remnant RX J1713.7-3946, and provides details on its temperature, elemental abundances, and inferred progenitor star mass through high-resolution X-ray spectroscopy observation.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Tianyin Luo, Hideyuki Umeda, Takashi Yoshida, Koh Takahashi
Summary: We study stellar models for Betelgeuse using the HR diagram and surface abundances as observational constraints. We find that initial mass, rotation velocity, and overshoot scheme impact the surface abundances and can be used as observational constraints. We investigate different initial mass models and examine the properties of red supergiants in detail. We find that the acceptable initial mass range for fitting Betelgeuse's surface abundances is 12-25 M (circle dot), but for nonrotating models, the range decreases to 15-24 M (circle dot).
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Chris Nagele, Hideyuki Umeda, Koh Takahashi, Takashi Yoshida, Kohsuke Sumiyoshi
Summary: A study investigates the formation of supermassive black holes in the early Universe and discovers a more accurate method for evaluating the general relativistic radial instability and earlier occurrence of the instability. It also identifies supernovae and pulsations resulting from this instability, providing new possibilities for observation and research.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Takuto Narita, Hiroyuki Uchida, Takashi Yoshida, Takaaki Tanaka, Takeshi Go Tsuru
Summary: Stellar winds from massive stars contain important information about the stars themselves, particularly carbon, nitrogen, and oxygen. Detecting and studying these elements in supernova remnants is challenging. In this study, the N vii Ly alpha line was detected for the first time in the young magnetar-hosting supernova remnant RCW 103. By comparing the abundance ratio of nitrogen to oxygen, the progenitor of RCW 103 was estimated to be a low mass star with medium rotation velocity. This study has implications for future missions in estimating progenitor parameters.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Koh Takahashi, Tomoya Takiwaki, Takashi Yoshida
Summary: Massive stars are connected with various astronomical processes and objects, and understanding their properties is crucial for modern astronomy. However, theoretical simulations have not been able to establish clear relations and have found complex interactions affecting the late evolutionary phases. In this study, we conducted stellar evolution simulations and found monotonous properties in the cores of massive stars, which can be considered an empirical principle characterizing them.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Masamichi Zaizen, Shunsaku Horiuchi, Tomoya Takiwaki, Kei Kotake, Takashi Yoshida, Hideyuki Umeda, John F. Cherry
Summary: This study investigates the multi-azimuthal angle effect on collective neutrino oscillation in a realistic supernova model, finding that this effect induces collective flavor conversions when completely suppressed. The results are validated by extending linear stability analysis into a three-flavor scheme including mixing angles.
Article
Astronomy & Astrophysics
Hideyuki Umeda, Takashi Yoshida, Chris Nagele, Koh Takahashi
ASTROPHYSICAL JOURNAL LETTERS
(2020)
Article
Astronomy & Astrophysics
Takashi Yoshida, Tomoya Takiwaki, Kei Kotake, Koh Takahashi, Ko Nakamura, Hideyuki Umeda
Summary: The study investigates turbulent mixing in the shell burning process of 22 and 27 solar mass stars in 3D simulations, revealing high turbulent Mach numbers. Turbulent mixing is influenced by episodic burning of O and Ne, leading to significant differences in the distribution of nucleosynthetic yields between 3D and 1D simulations.
ASTROPHYSICAL JOURNAL
(2021)
