Nuclear Theory·nucl-th

Friday·September 29, 2023

8 papers—5 primary·3 cross-listed

01
[Submitted on 26 Sept 2023]
Atomic corrections for the unique first forbidden $β$ transition of $^{187}$ Re
O. Niţescu🇸🇰 · R. Dvornický🇸🇰 · F. Šimkovic🇸🇰
In this paper, we reexamine one of the most promising candidates for determining the neutrino mass scale -- the unique first forbidden $β$ transition from $^{187}$ Re( $5/ 2^{+}$ ) to $^{187}$ Os( $1/ 2^{-}$ ). With the lowest-known ground-state to ground-state $Q$ -value for a $β$ transition at $2.4709$ keV, rhenium's $β$ decay can offer insights into the neutrino mass scale puzzle. However, understanding its electron spectrum is a complex task. Besides involving a mixture of $s_{1/2}$ -state and $p_{3/2}$ -state electrons, the rhenium $β$ spectrum could be strongly influenced by various atomic corrections. In addition to our previous paper, we have incorporated finite nuclear size, diffuse nuclear surface, screening, and exchange corrections into the rhenium $β$ decay model. We have accounted for the last two effects within the framework of the Dirac-Hartree-Fock-Slater self-consistent method. We have discovered that both screening and exchange effects significantly alter the partial decay rates for the $s_{1/2}$ - and $p_{3/2}$ -state emission channels, while still maintaining the experimentally confirmed dominance of the $p_{3/2}$ -state emission. The ratio between the respective decay rates has been found to be approximately $1 0^{4}$ . When compared to the other corrections, the exchange effect stands out due to the modification it induces in the spectrum shape. We demonstrate that calculations with and without the exchange effect lead to entirely different shape factors for the decay spectrum. Finally, we illustrate that to preserve the linearity of the Kurie plot, it is essential to include the exchange correction in its definition. We conclude that atomic effects, especially the exchange effect, should be taken into account in current and future investigations of the neutrino mass scale from $β$ decays.
Comments:
13 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2309.15918 [pdf]
PRC(2024)·9 citations
02
[Submitted on 28 Sept 2023]
Production properties of deuterons, helions and tritons via an analytical nucleon coalescence method in Pb-Pb collisions at $s_{N N} = 2.76$ TeV
Rui-Qin Wang🇨🇳 · Yan-Hao Li🇨🇳 · Jun Song🇨🇳 · Feng-Lan Shao🇨🇳
We improve a nucleon coalescence model to include the coordinate-momentum correlation in nucleon joint distributions, and apply it to Pb-Pb collisions at $s_{N N} = 2.76$ TeV to study production properties of deuterons ( $d$ ), helions ( $^{3}$ He) and tritons ( $t$ ). We give formulas of the coalescence factors $B_{2}$ and $B_{3}$ , and naturally explain their behaviors as functions of the collision centrality and the transverse momentum per nucleon $p_{T} / A$ . We reproduce the transverse momentum spectra, averaged transverse momenta and yield rapidity densities of $d$ , $^{3}$ He and $t$ , and find the system effective radius obtained in the coalescence production of light nuclei behaves similarly to Hanbury Brown-Twiss interferometry radius. We particularly give expressions of yield ratios $d / p$ , $^{3}$ He $/ d$ , $t / p$ , $^{3}$ He $/ p$ , $d / p^{2}$ , $^{3}$ He $/ p^{3}$ , $t /^{3}$ He and argue their nontrivial behaviors can be used to distinguish production mechanisms of light nuclei.
Comments:
12 pages, 8 figures, 1 table
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2309.16296 [pdf]
PRC(2024)·10 citations
03
[Submitted on 28 Sept 2023]
Radiative Corrections and the Renormalization Group for the Two-Nucleon Interaction in Effective Field Theory
Thomas R. Richardson🇩🇪 · Immo C. Reis🇩🇪
We use a combination of effective field theory and the renormalization group to determine the impact of radiative corrections on the nucleon-nucleon potential and the binding energy of the deuteron. In order to do so, we present a modified version of pionless effective field theory inspired by earlier work in nonrelativistic quantum electrodynamics. The renormalization group improvement of the deuteron binding energy leads to a shift on the order of a few percent and is consistent with the experimental value. This work serves as a starting point for a dedicated study of radiative corrections in few-body systems relevant for precision tests of the Standard Model in an effective field theory framework.
Comments:
16 pages, 3 figures, title change, expanded
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2309.16385 [pdf]
Few Body Syst.(2024)·4 citations
04
[Submitted on 28 Sept 2023]
Sound velocity, equation of state and strangeness in neutron star matter
Wolfram Weise🇩🇪
This presentation in two parts starts with a brief review on the speed of sound in neutron star matter as inferred from observational data. It is pointed out that, in view the strong constraints imposed by observed properties of the heaviest neutron stars, the equation of state must be very stiff. Stringent limits can be set on the possible appearance of phase transitions in neutron star cores. The second part discusses issues concerning the occurance of strangeness degrees of freedom, in particular of hyperons, in neutron stars. Here a focus is on the role of repulsive hyperon-nuclear three-body forces, potentially resolving the so-called hyperon puzzle.
Comments:
6 pages, 4 figures, Proceedings MESON2023, EPJ Web Conf
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2309.16438 [pdf]
EPJ Web Conf.(2024)·6 citations
05
[Submitted on 28 Sept 2023]
Signatures of $α$ -clustering in $^{12}$ C and $^{13}$ C
A.H. Santana-Valdés · R. Bijker
We study the cluster structure of $^{12}$ C and $^{13}$ C in the framework of the cluster shell model. Simple relations are derived for ratios of longitudinal form factors as well as transition probabilities. It is shown that the available experimental data for $^{12}$ C and $^{13}$ C can be well described by a triangular structure with $D_{3 h}$ and $D_{3 h}^{'}$ symmetry, respectively.
Comments:
11 pages, 4 figures, 2 tables, Phys. Lett. B
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2309.16586 [pdf]
PLB(2023)·4 citations
06
[Submitted on 27 Sept 2023] (cross-list from hep-ph)
All orders factorization and the Coulomb problem
Richard J. Hill🇺🇸 · Ryan Plestid🇺🇸
In the limit of large nuclear charge, $Z ≫ 1$ , or small lepton velocity, $β ≪ 1$ , Coulomb corrections to nuclear beta decay and related processes are enhanced as $Z α / β$ and become large or even non-perturbative (with $α$ the QED fine structure constant). We provide a constructive demonstration of factorization to all orders in perturbation theory for these processes and compute the all-orders hard and soft functions appearing in the factorization formula. We clarify the relationship between effective field theory amplitudes and historical treatments of beta decay in terms of a Fermi function.
Comments:
Matches journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2309.15929 [pdf]
PRD(2024)·27 citations
07
[Submitted on 28 Sept 2023] (cross-list from hep-ph)
Analysis of $Ξ (1620)$ resonance with chiral unitary approach
Takuma Nishibuchi🇯🇵 · Tetsuo Hyodo🇯🇵
Recently, the $Ξ (1620)$ resonance has attracted much attention, thanks to detailed experimental data by the Belle and ALICE collaborations. This experimental progress has prepared us to conduct theoretical analyses based on experimental data. In this study, we analyze the $Ξ (1620)$ resonance using the chiral unitary model and discuss the properties of the $Ξ (1620)$ resonance and the $K^{-} Λ$ scattering length.
Comments:
4 pages, 2 figures, Proceedings of 17th International Workshop on Meson Physics (MESON2023), 22nd - 27th June, 2023
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.16420 [pdf]
EPJ Web Conf.(2024)·1 citation
08
[Submitted on 28 Sept 2023] (cross-list from hep-ph)
Low and moderate $x$ gluon contribution to exclusive Compton scattering processes
Renaud Boussarie🇫🇷 · Yacine Mehtar-Tani🇺🇸
We revisit the high energy semi-classical description of the exclusive processes DVCS, TCS, and Double DVCS by explicitly keeping track of the Feynman $x$ dependence in both the hard and the hadronic matrix elements. This is achieved by a modification of the standard shock wave approximation to derive the effective Feynman rules, which leads to a generic expression on which we then perform a partial twist expansion to get rid of quantities suppressed by the proper physical scales. We obtain a compact factorized master formula that can be used to investigate the Bjorken limit at leading twist. In particular, we recover the full one-loop result in the collinear limit for pure gluon exchange with the target. Finally, we discuss the subtleties in taking the simultaneous collinear and small $x$ limit.
Comments:
43 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.16576 [pdf]
JHEP(2024)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE