Nuclear Theory·nucl-th

Tuesday·April 26, 2022

9 papers—4 primary·5 cross-listed

01
[Submitted on 22 Apr 2022]
Event-by-event anti-deuteron multiplicity fluctuation in Pb+Pb collisions at $s_{N N} = 5.02$ TeV
Kai-Jia Sun🇨🇳 · Che Ming Ko🇺🇸
Using the nucleon coalescence model based on kinetic freeze-out nucleons from the hybrid model of MUSIC hydrodynamics and UrQMD hadronic transport, we study the production of anti-deuteron and its event-by-event fluctuation in Pb+Pb collisions at $s_{N N} = 5.02$ TeV. We find a clear suppression of the anti-deuteron to antiproton yield ratio in peripheral collisions, which is in accordance with the measurements from the ALICE Collaboration. Also found is a Poissonian event-by-event fluctuation of the anti-deuteron multiplicity distribution in all collision centralities, which is different from the prediction of a simple coalescence model calculation that assumes all antiproton and antineutron pairs to have the same probability to form anti-deuterons. We further find a small negative correlation between the anti-deuteron and antiproton multiplicity distributions as a result of the baryon conservation.
Comments:
5 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2204.10879 [pdf]
PLB(2023)·10 citations
02
[Submitted on 23 Apr 2022]
The relationship of the neutron-skin thickness to the symmetry energy and its slope
Toshio Suzuki
The neutron-skin thickness of asymmetric semi-infinite nuclear matter is shown to be a function of Coulomb energy, the asymmetry-energy coefficient( $J$ ), the slope( $L$ ) of the asymmetry energy, and the incompressibility coefficient, in addition to he Fermi momentum and the asymmetry parameter. The relational formula is derived on the basis of the Hugenholtz-Van Hove theorem in the mean-field approximation for nuclear matter. Using the formula as a guide, the neutron-skin thickness( $δ R$ ) in $^{208}$ Pb is examined. The linear correlation between $L$ and $δ R$ appears as a kind of spurious ones through the model-dependent correlation of $L$ with $J$ which is included in the main components of the formula.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2204.11013 [pdf]
PTEP(2022)·11 citations
03
[Submitted on 24 Apr 2022]
Exploring the ground state bulk and decay properties of the nuclei in superheavy island
Nishu Jain · Raj Kumar · M. Bhuyan
The $α$ -decay half-lives of 204 superheavy nuclei covering the range $114 \leq Z \leq 126$ have been investigated using the relativistic mean-field model (RMF) for NL3 $^{*}$ parameter set. The ground state bulk properties such as binding energy, quadrupole deformation parameter ( $β_{2}$ ), and root-mean-square charge radii for these nuclei are analyzed. Four different semi-empirical formulae, namely, the universal decay law (UDL), the Viola-Seaborg (VSS) formula, the modified universal decay law (MUDL), and the modified Brown formula (MBrown), are used to obtain the $α$ -decay half-lives for the considered nuclei. To examine the applicability of relativistic mean-field model within NL3 $^{*}$ parametrization, the $α$ -decay energies, and the half-lives of a few known superheavy nuclei within the range 102 $\leq$ Z $\leq$ 118 are calculated and the results are compared with the experimental data along with the theoretical predictions. The $α$ -decay energies ( $Q$ -values) are estimated from the binding energies of the parent, and daughter from the RMF (NL3 $^{*}$ ) parameter set. The calculated results are compared with macroscopic-microscopic Finite-Range-Droplet-Model (FRDM), Global Nuclear Mass Model (WS3, WS4), Weizsacker-Skyrme mass model (WS $^{*}$ ) predictions, and the experimental data, wherever available. The possible standard deviations are also estimated for experimental and various theoretical predictions. We find a good consistency for the experimental-to-UDL, FRDM-to-UDL, and WS4-to-UDL estimates of the decay energy and corresponding half-life. The present analysis provides the theoretical predictions within the microscopic model for the upcoming experiments on the superheavy region.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2204.11173 [pdf]
NPA(2022)·5 citations
04
[Submitted on 25 Apr 2022]
Pairing enhancement in a two-neutron transfer process through the continuum
Gagandeep Singh · Lorenzo Fortunato · Andrea Vitturi
Enhancement, due to constructive interference through the many possible reaction channels, occurs in two-neutron transfer reactions from a bound system $A$ to a weakly-bound system ( $A$ +2), whenever the intermediate system is unbound and consists of a continuum with a resonant state. We elucidate this phenomenon in the case of $^{6}$ He, modeled as two neutrons in the orbitals of an intermediate $^{5}$ He nucleus, comparing the realistic case of an unbound ( $A$ +1) system with an artificially bound case. A properly modeled continuum in these calculations is found to be crucial and leads to significant enhancement due to pairing correlations.
Comments:
9 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2204.11739 [pdf]
PLB(2022)·8 citations
05
[Submitted on 22 Apr 2022] (cross-list from hep-ph)
Chiral magnetic effect in heavy ion collisions and beyond
Dmitri E. Kharzeev🇺🇸
Chirality is a ubiquitous concept in modern science, from particle physics to biology. In quantum physics, chirality of fermions is linked to topology of gauge fields by the chiral anomaly. While the chiral anomaly is usually associated with the short-distance behavior in field theory, in recent years it has been realized that it also affects the macroscopic behavior of systems with chiral fermions. In particular, the local imbalance between left- and right-handed fermions in the presence of a magnetic field induces non-dissipative transport of electric charge ("the Chiral Magnetic Effect", CME). In heavy ion collisions, there is an ongoing search for this effect at Relativistic Heavy Ion Collider, with results from a dedicated isobar run presented very recently. An observation of CME in heavy ion collisions could shed light on the mechanism of baryon asymmetry generation in the Early Universe. Recently, the CME has been discovered in Dirac and Weyl semimetals possessing chiral quasi-particles. This observation opens a path towards quantum sensors, and potentially a new kind of quantum computers.
Comments:
12 pages; to appear in the Proceedings of Nobel Symposium 167: "Chiral Matter", Stockholm, June 2021
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2204.10903 [pdf]
9 citations
06
[Submitted on 24 Apr 2022] (cross-list from hep-ph)
Theory of QED radiative corrections to neutrino scattering at accelerator energies
Oleksandr Tomalak🇺🇸 · Qing Chen🇺🇸 · Richard J Hill🇺🇸 · Kevin S McFarland🇺🇸 · Clarence Wret🇺🇸
Control over quantum electrodynamics (QED) radiative corrections is critical for precise determination of neutrino oscillation probabilities from observed (anti)neutrino detection rates. It is particularly important to understand any difference between such corrections for different flavors of (anti)neutrinos in charged-current interactions. We provide theoretical foundations for calculating these corrections. Using effective field theory, the corrections are shown to factorize into soft, collinear, and hard functions. The soft and collinear functions contain large logarithms in perturbation theory but are computable from QED. The hard function parametrizes hadronic structure but is free from large logarithms. Using a simple model for the hard function, we investigate the numerical impact of QED corrections in charged-current (anti)neutrino-nucleon elastic cross sections and cross-section ratios at GeV energies. We consider the implications of mass singularity theorems that govern the lepton-mass dependence of cross sections for sufficiently inclusive observables and demonstrate the cancellation of leading hadronic and nuclear corrections in phenomenologically relevant observables.
Comments:
43 pages, 27 figures, v2: journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2204.11379 [pdf]
PRD(2022)·41 citations
07
[Submitted on 25 Apr 2022] (cross-list from hep-ph)
$ϕ$ meson properties in nuclear matter from QCD sum rules with chirally separated four-quark condensates
Jisu Kim🇰🇷 · Philipp Gubler🇯🇵 · Su Houng Lee🇰🇷
The modification of the $ϕ$ meson spectrum in nuclear matter is studied in an updated QCD sum rule analysis, taking into account recent improvements in properly treating the chiral invariant and breaking components of four-quark condensates. Allowing both mass and decay width to change at finite density, the QCD sum rule analysis determines certain combinations of changes for these parameters that satisfy the sum rules equally well. A comprehensive error analysis, including uncertainties related to the behavior of various condensates at linear order in density, the employed renormalization scale and perturbative corrections of the Wilson coefficients, is used to compute the allowed ranges of these parameter combinations. We find that the $ϕ$ meson mass shift in nuclear matter is especially sensitive to the strange sigma term $σ_{s N}$ , which determines the decrease of the strange quark condensate in nuclear matter. Specifically, we obtain a linear relation between the width $Γ_{ϕ}$ and mass shift $Δ m_{ϕ}$ given as $Γ_{ϕ} = a Δ m_{ϕ} + b σ_{s N} + c$ with $a = (3.94 7_{- 0.130}^{+ 0.139})$ , $b = (0.93 6_{- 0.177}^{+ 0.180})$ and $c = - (7.70 7_{- 5.679}^{+ 4.791}) MeV$ .
Comments:
9 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.11440 [pdf]
PRD(2022)·13 citations
08
[Submitted on 25 Apr 2022] (cross-list from hep-ph)
Quantum kinetic theory for dynamical spin polarization from QED-type interaction
Shuo Fang🇨🇳 · Shi Pu🇨🇳 · Di-Lun Yang🇹🇼
We investigate the dynamical spin polarization of a massless electron probing an electron plasma in locally thermal equilibrium via the Moller scattering from the quantum kinetic theory. We derive an axial kinetic equation delineating the dynamical spin evolution in the presence of the collision term with quantum corrections up to $O (ℏ)$ and the leading-logarithmic order in coupling by using the hard-thermal-loop (HTL) approximation, from which we extract the spin-polarization rate induced by the spacetime gradients of the medium. When the electron probe approaches local equilibrium, we further simplify the collision term into a relaxation-time expression. Our kinetic equation may be implemented in the future numerical simulations for dynamical spin polarization.
Comments:
28 pages, 1 figure, minor revisions, journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2204.11519 [pdf]
PRD(2022)·50 citations
09
[Submitted on 25 Apr 2022] (cross-list from hep-ph)
Impact of Charge Symmetry Breaking on Gluon and Sea Quark Distributions in the Pion and Kaon
Parada T. P. Hutauruk🇰🇷
In this exploratory study, I present, for the first time, the implications of the charge symmetry breaking (CSB) that arise from the $u$ and $d$ quark mass differences on gluon and sea quark distribution functions of the pion and kaon in the framework of the Nambu--Jona-Lasino (NJL) model, which is a quark-level chiral effective theory of QCD, with the help of the proper-time regularization scheme to simulate color confinement of QCD. From the analysis, one finds that the charge symmetry (CS) gluon distribution for the pion has a good agreement with the prediction results obtained from the recent lattice QCD simulation and JAM global fit QCD analysis at a higher scale of $Q^{2} =$ 5 GeV $^{2}$ . The size of the CSB effects on gluon and sea quark distributions for the pion with the realistic ratios of $m_{u} / m_{d} = 0.5$ at $Q^{2} =$ 5 GeV $^{2}$ are respectively estimated by 1.3\% and 2.0\% at $x ≃ 1$ in comparison with those for $m_{u} / m_{d} = 1.0$ , while those for the kaon are approximately about 0.3\% and 0.5\% at $x ≃ 1$ , respectively. A remarkable result is found that the CSB effects on gluon distribution for the kaon are smaller than that for the pion, which has a similar prediction result as that for the CS case.
Comments:
12 pages, 1 table, 15 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.11520 [pdf]
Mod.Phys.Lett.A(2023)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE