Level structures of Ca cast doubt on a doubly magic Ca

Chen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.

Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08

https://doi.org/10.1016/j.physletb.2023.138025

Gamma decays were observed in Ca and Ca following quasi-free one-proton knockout reactions from Sc. For Ca, a ray transition was measured to be 1456(12) keV, while for Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the and orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic Ca and potentially drives the dripline of Ca isotopes to Ca or even beyond.

Elastic properties of nuclear pasta in a fully three-dimensional geometry

Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*; Zhang, Y.-X.*

Physics Letters B, 839, p.137769_1 - 137769_5, 2023/04

https://doi.org/10.1016/j.physletb.2023.137769

Pole position of measured in reactions

Aikawa, Shu*; Hashimoto, Tadashi; Tanida, Kiyoshi; 73 of others*

Physics Letters B, 837, p.137637_1 - 137637_8, 2023/02

https://doi.org/10.1016/j.physletb.2022.137637

First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic Pb

Zhang, W. Q.*; Andreyev, A. N.; Liu, Z.*; Seweryniak, D.*; Huang, H.*; Li, Z. H.*; Li, J. G.*; Guo, C. Y.*; 34 of others*

Physics Letters B, 829, p.137129_1 - 137129_7, 2022/06

https://doi.org/10.1016/j.physletb.2022.137129

Doubly heavy tetraquark resonant states

Meng, Q.*; Harada, Masayasu*; Hiyama, Emiko; Hosaka, Atsushi; Oka, Makoto

Physics Letters B, 824, p.136800_1 - 136800_5, 2022/01

https://doi.org/10.1016/j.physletb.2021.136800

Spectrum of the doubly heavy tetraquarks, , is studied in a constituent quark model. Four-body problem is solved in a variational method where the real scaling technique is used to identify resonant states above the fall-apart decay thresholds. In addition to the two bound states that were reported in the previous study we have found several narrow resonant states above the and thresholds. Their structures are studied and are interpreted by the quark dynamics. A narrow resonance with spin-parity is found to be a mixed state of a compact tetraquark and a scattering state. This is driven by a strong color Coulombic attraction between the quarks. Negative-parity excited resonances with , and form a triplet under the heavy-quark spin symmetry. It turns out that they share a similar structure to the -mode of a singly heavy baryon as a result of the strongly attractive correlation for the doubly heavy diquark.

Transition probabilities in P and S; A Test for isospin symmetry

Tonev, D.*; De Angelis, G.*; Deloncle, I.*; Orlandi, R.; 27 of others*

Physics Letters B, 821, p.136603_1 - 136603_6, 2021/10

https://doi.org/10.1016/j.physletb.2021.136603

Survival probabilities of charmonia as a clue to measure transient magnetic fields

Iwasaki, Sachio*; Jido, Daisuke*; Oka, Makoto; Suzuki, Kei

Physics Letters B, 820, p.136498_1 - 136498_6, 2021/09

https://doi.org/10.1016/j.physletb.2021.136498

We investigate time evolution of -wave charmonium populations under a time-dependent homogeneous magnetic field and evaluate survival probabilities of the low-lying charmonia to the goal of estimating the magnetic field strength at heavy-ion collisions. Our approach implements mixing between different spin eigenstates and transitions to radially excited states. We show that the survival probabilities can change even by an extremely short magnetic field. Furthermore, we find that the survival probabilities depend on the initial spin states. We propose the sum of the survival probabilities over spin partners as an observable insensitive to the initial states. We also find that the sum can be approximately given as a function of with a duration time and the maximum strength of the magnetic field .

Stable double-heavy tetraquarks; Spectrum and structure

Meng, Q.*; Hiyama, Emiko*; Hosaka, Atsushi; Oka, Makoto; Gubler, P.; Can, K. U.*; Takahashi, Toru*; Zong, H. S.*

Physics Letters B, 814, p.136095_1 - 136095_6, 2021/03

https://doi.org/10.1016/j.physletb.2021.136095

Beta decay of the axially asymmetric ground state of Re

Watanabe, Hiroshi*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Andreyev, A. N.; Hashimoto, Takashi*; Kondev, F. G.*; Lane, G. J.*; Litvinov, Yu. A.*; Liu, J. J.*; Miyatake, Hiroari*; et al.

Physics Letters B, 814, p.136088_1 - 136088_6, 2021/03

https://doi.org/10.1016/j.physletb.2021.136088

Casimir effect for lattice fermions

Ishikawa, Tsutomu*; Nakayama, Katsumasa*; Suzuki, Kei

Physics Letters B, 809, p.135713_1 - 135713_7, 2020/10

AA2020-0811.pdf:0.54MB

https://doi.org/10.1016/j.physletb.2020.135713

We propose a definition of the Casimir energy for free lattice fermions. From this definition, we study the Casimir effects for the massless or massive naive fermion, Wilson fermion, and (Mbius) domain-wall fermion in 1+1 dimensional spacetime with the spatial periodic or antiperiodic boundary condition. For the naive fermion, we find an oscillatory behavior of the Casimir energy, which is caused by the difference between odd and even lattice sizes. For the Wilson fermion, in the small lattice size of , the Casimir energy agrees very well with that of the continuum theory, which suggests that we can control the discretization artifacts for the Casimir effect measured in lattice simulations. We also investigate the dependence on the parameters tunable in Mbius domain-wall fermions. Our findings will be observed both in condensed matter systems and in lattice simulations with a small size.