Thu·Oct 6, 2022Thursday·October 6, 2022

1. 01*

   Charge radii of ${}^{55,56}$Ni reveal a surprisingly similar behavior at $N=28$ in Ca and Ni isotopes

   F. Sommer🇩🇪 · K. König🇩🇪 · D.M. Rossi🇰🇷 · N. Everett · D. Garand · R.P. de Groote🇧🇪 · J.D. Holt🇨🇦 · P. Imgram🇩🇪 · A. Incorvati🇺🇸 · C. Kalman · A. Klose · J. Lantis🇺🇸 and 15 other authors

   Nuclear charge radii of ${}^{55,56}$Ni were measured by collinear laser spectroscopy. The obtained information completes the behavior of the charge radii at the shell closure of the doubly magic nucleus ${}^{56}$Ni. The trend of charge radii across the shell closures in calcium and nickel is surprisingly similar despite the fact that the ${}^{56}$Ni core is supposed to be much softer than the ${}^{48}$Ca core. The very low magnetic moment $\mu {(}^{55}\mathrm{Ni})=-1.108(20){\mu }_N$ indicates the impact of M1 excitations between spin-orbit partners across the $N,Z=28$ shell gaps. Our charge-radii results are compared to \textit{ab initio} and nuclear density functional theory calculations, showing good agreement within theoretical uncertainties.

   nucl-exnucl-thPRL(2022)·55 citations
2. 02*

   TriSol: a major upgrade of the TwinSol RNB facility

   P.D. O'Malley · T. Ahn🇺🇸 · D.W. Bardayan🇺🇸 · M. Brodeur🇺🇸 · S. Coil · J. J. Kolata

   We report here on the recent upgrade of the TwinSol radioactive nuclear beam (RNB) facility at the University of Notre Dame. The new TriSol system includes a magnetic dipole to provide a second beamline and a third solenoid which acts to reduce the size of the radioactive beam on target.

   ↳ physics.acc-phnucl-exNucl.Instrum.Meth.A(2023)·8 citations
3. 03*

   Parity-doublet bands in the odd-\bm{$A$} isotones \element{237}U and \element{239}Pu by a particle-number-conserving method based on the cranked shell model

   Jun Zhang · Xiao-Tao He

   Based on the reflection-asymmetric Nilsson potential, the parity-doublet rotational bands in odd-$A$ isotones \element{237}U and \element{239}Pu have been investigated by using the particle-number-conserving (PNC) method in the framework of the cranked shell model (CSM). The experimental kinematic moments of inertia (MOIs) and angular momentum alignments are reproduced very well by the PNC-CSM calculations. The significant differences of rotational properties between \element{237}U and \element{239}Pu are explained with the contribution of nucleons occupying proton octupole-correlation pairs of ${\pi }^2{i}_{13/2}{f}_{7/2}$. The upbendings of moments of inertia of the parity-doublet bands in \element{237}U are due to the interference terms of alignments of protons occupying $\pi f_{7/2}$ ($1/2$) and the high-$j$ intruder $\pi i_{13/2}$ $(1/2,3/2)$ orbitals. The splittings between the simplex partner bands of the parity-doublet bands in both \element{237}U and \element{239}Pu result from the contribution of alignment of neutron occupying the $\nu d_{5/2}$ ($1/2$) orbital.

   ↳ nucl-thnucl-exPRC(2023)·4 citations
4. 04*

   Proposal for Measurement of the Two-body Neutron Decay using Microcalorimeter

   Zhang Shuo🇨🇳 · Xavier Mougeot🇫🇷 · Wang Song-Lin🇨🇳 · Zhou Jian-Rong🇨🇳 · Wu Wen-Tao🇨🇳 · Xia Jing-Kai🇨🇳 · Zhang Rui-Tian🇨🇳 · Zhang Le🇨🇳

   The bound beta-decay (BoB) of neutron is also known as the two-body neutron decay, which is a rare decay mode into a hydrogen atom and an anti-neutrino. The state of neutrino can be exactly inferred by measuring the state of hydrogen atom, providing a possible pathway to explore new physics. However, this rare decay mode has not yet been observed so far since it was predicted in 1947. The challenge in observing this decay is not only that its cross section is extremely low, equivalent to about branching ratio of the order of $10^{-6}$ of the three-body decay, but also that the final-state hydrogen atom is neutral and has extremely low kinetic energy, which cannot be effectively detected. In this study, we propose a microcalorimeter-based scheme for measuring the kinetic energies of hydrogen atoms produced from BoB of ultracold neutrons, which has a great advantage in terms of accuracy of the energy measurement. In this study, first, several important issues that require rigorous considerations for the decay measurements and possible solutions are discussed. Then, the requirements of the neutron flux and the appropriate structure design of the microcalorimeter are present by theoretical calculations. In short, this paper outlines our proposed novel experimental scheme for observing the BoB mode, addressing the possible solutions to all the necessary problems.

   ↳ hep-exnucl-exphysics.atom-ph1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.