Nuclear Theory·nucl-th

Thursday·May 5, 2022

8 papers—6 primary·2 cross-listed

01
QCD equation of state with Tsallis statistics for heavy-ion collisions
K. Kyan🇯🇵 · A. Monnai🇯🇵
Nonextensive statistics has attracted attention as a description of particle spectra in nuclear collisions at QCD energies. First, we construct the equation of state by incorporating Tsallis statistics based on the hadron resonance gas and parton gas models. Thermodynamic conditions are found to impose constraints on the $q$ -parameter of Tsallis distribution. Next, we apply the equation of state to the relativistic hydrodynamic modeling of nuclear collisions. The Cooper-Frye prescription is consistently modified. Numerical demonstrations indicate that the model may describe charged particle spectra at Large Hadron Collider in the transverse momentum range up to 6-8 GeV. Elliptic flow, on the other hand, suggests a narrower range of applicability.
nucl-thhep-phnucl-exPRD(2022)·14 citations
02
Enhanced moments of inertia for rotation in neutron-rich nuclei
Kenichi Yoshida
Ground-state moments of inertia (MoI) are investigated for about 1700 even-even nuclei from the proton drip line to the neutron drip line up to $Z = 120$ and $N = 184$ . The cranked Skyrme-Hartree-Fock-Bogoliubov equation is solved in the coordinate space. This model describes well the available experimental data of more than 300 nuclides possessing an appreciable deformation. I find that the MoI greatly increase near the drip line whereas the deformation is not as strong as estimated by the empirical relation. Systematic measurements of the excitation energy and the transition probability to the first $I^{π} = 2^{+}$ state in neutron-rich nuclei not only reveal the evolution of deformation but can also constrain an effective pair interaction.
nucl-thnucl-exPLB(2022)·0 citations
03
Perturbative Calculations of Deuteron Form Factors
Wenchao Shi🇨🇳 · Rui Peng🇨🇳 · Tai-Xing Liu🇨🇳 · Songlin Lyu🇨🇳 · Bingwei Long🇨🇳
We calculate the deuteron charge, electric quadrupole, and magnetic form factors up to next-to-next-to-leading order in chiral effective field theory, treating subleading corrections, especially that of chiral nuclear forces, in perturbation theory. We examine the power counting based on naive dimensional analysis by investigating the ultraviolet cutoff variation of these form factors. We find that the N $^{2}$ LO magnetic form factor shows significant cutoff dependence, suggesting the contact current operator responsible be enhanced. After promotion to N $^{2}$ LO, it indeed renormalizes the magnetic form factor. This is in agreement with a previous work based on renormalization-group analysis. For the charge and quadrupole moments, perturbative calculation allows us to study how they scale with multiple low-energy parameters such as the pion mass, deuteron binding momentum, and momentum transfer.
nucl-thPRC(2022)·9 citations
04
Radial oscillations in neutron stars from unified hadronic and quarkyonic equation of states
Souhardya Sen · Shubham Kumar · Athul Kunjipurayi · Pinku Routaray · Tianqi Zhao · Bharat Kumar
We study radial oscillations in non-rotating neutron stars by considering the unified equation of states (EoSs), which support the 2 M $_{⊙}$ star criterion. We solve the Sturm-Liouville problem to compute 20 lowest radial oscillation modes and their eigenfunctions for neutron star modelled with eight selected unified EoSs from distinct Skyrme-Hartree Fock, Relativistic Mean-Field and quarkyonic models. We compare the behavior of the computed eigenfrequency for NS modelled with hadronic to that with quarkyonic EoSs while varying central densities. The lowest order, f-mode frequency varies substantially between the two classes of the of EoS at 1.4 M $_{⊙}$ but vanishes at their respective maximum masses, consistent with the stability criterion $\partial M / \partial ρ_{c} > 0$ . Moreover, we also computed large frequency separation and discovered that higher-order mode frequencies are significantly reduced by incorporating crust in the EoS.
nucl-thgr-qcGalaxies(2023)·28 citations
05
Impact of the equation of state on $f$ - and $p$ - mode oscillations of neutron stars
Athul Kunjipurayil · Tianqi Zhao · Bharat Kumar · Bijay K. Agrawal · Madappa Prakash
We investigate the impact of the neutron-star matter equation of state on the $f$ - and $p_{1}$ -mode oscillations of neutron stars obtained within the Cowling approximation and linearized general relativity. The $f$ - and $p_{1}$ -mode oscillation frequencies, and their damping times are calculated using representative sets of Skyrme Hartree-Fock and relativistic mean-field models, all of which reproduce nuclear systematics and support $2 M_{⊙}$ neutron stars. Our study shows strong correlations between the frequencies of $f$ - and $p_{1}$ -modes and their damping times with the pressure of $β$ -equilibrated matter at densities equal to or slightly higher than the nuclear saturation density $ρ_{0}$ . Such correlations are found to be almost independent of the composition of the stars. The frequency of the $p_{1}$ -mode of $1.4 M_{⊙}$ star is strongly correlated with the slope of the symmetry energy $L_{0}$ and $β$ -equilibrated pressure at density $ρ_{0}$ . Compared to GR calculations, the error in the Cowling approximation for the $f$ -mode is about 30\% for neutron stars of low mass, whereas it decreases with increasing mass. The accuracy of the $p_{1}$ -mode is better than 15\% for neutron stars of maximum mass, and improves for lower masses and higher number of radial nodes.
nucl-thgr-qcPRD(2022)·65 citations
06
Effective Mass of $α$ -Cluster in $^{12}$ C Nucleus
Igor Filikhin · Abdennaceur Karoui · Branislav Vlahovic
Based on the effective-mass concept, we perform the Faddeev calculations for a low-lying spectrum of 3 $α$ states in $^{12}$ C nucleus. A three-body potential is used to describe the known breaking of the 3 $α$ -cluster structure in the nucleus. We show that the contribution of the three-body potential to the Hamiltonian can be compensated by increasing/decreasing the $α$ -particle free mass. The effective-mass values are adjusted so that to reproduce the experimental data for the $^{12}$ C nucleus. The energy dependence of the effective mass and the correlation to a three-body potential are discussed. We show that the coupling between the $0^{+}$ ( $2^{+}$ ) levels forms a specific picture of anti-crossing on the energy/effective-mass plane.
nucl-thIJMPE(2022)·6 citations
07
Improved Limit on Tensor Currents in the Weak Interaction from $^{8}$ Li $β$ Decay
M. T. Burkey · G. Savard · A. T. Gallant · N. D. Scielzo · T. Y. Hirsh · L. Varriano · G. H. Sargsyan · K. D. Launey · M. Brodeur · D. P. Burdette · E. Heckmaier · K. Joerres and 19 other authors
The electroweak interaction in the Standard Model (SM) is described by a pure vector-axial-vector structure, though any Lorentz-invariant component could contribute. In this work, we present the most precise measurement of tensor currents in the low-energy regime by examining the $β$ - $ν ˉ$ correlation of trapped $^{8}$ Li ions with the Beta-decay Paul Trap. We find $a_{β ν} = - 0.3325 \pm 0.001 3_{s t a t} \pm 0.001 9_{sy s t}$ at $1 σ$ for the case of coupling to right-handed neutrinos $(C_{T} = - C_{T}^{'})$ , which is consistent with the SM prediction.
↳ nucl-exhep-phnucl-thPRL(2022)·38 citations
08
Constraints on the dark photon from parity violation and the $W$ mass
A. W. Thomas🇦🇺 · X. G. Wang🇦🇺
We present an analysis of the experimental data for parity-violating electron scattering (PVES) and atomic parity-violation, including the effects of a dark photon. We derive the favored region of dark photon parameter space, which provides a good description of the experimental data from the Qweak Collaboration and the Jefferson Lab PVDIS Collaboration and simultaneously relieves the tension between the neutron skin thickness determined in the PREX-II experiment and nuclear-model predictions. In addition, we extract the parameter region required to explain the latest W-boson mass anomaly. Our results indicate that a heavy dark photon with mass above the Z boson mass is favored, while other sources of new physics beyond the Standard Model in addition to the dark photon would also be expected.
↳ hep-phhep-exnucl-thPRD(2022)·28 citations

Affiliations

first authorsco-authorsvia INSPIRE