Nuclear Theory·nucl-th

Wednesday·August 31, 2022

10 papers—4 primary·6 cross-listed

01
Ground state correlations on ground state densities and total binding energies of 40Ca, 48Ca and 208Pb
F. Minato · H. Sagawa · S. Yoshida
Neutron and proton densities of doubly-closed shell nuclei 40Ca, 48Ca and 208Pb are studied based on a Hartree-Fock model with SAMi, SAMi-J27 and SAMi-T energy density functionals (EDFs). The ground state correlations (GSC) induced by isoscalar and isovector phonons are also evaluated by the second order perturbation theory with a self-consistent random phase approximation (RPA). We found that the interior part of the ground state densities is reduced by the GSC in consistent with the experimental data. On the other hand, the GSC enhances the neutron skin thickness of 48Ca and 208Pb. The effect of GSC on the total binding energy is also evaluated by the quasi-boson approximation. The effect of the tensor interaction is found small on both the density distributions and the binding energies.
nucl-thnucl-ex1 citation
02
Multi-task learning on nuclear masses and separation energies with the kernel ridge regression
X.H. Wu · Y.Y. Lu · P.W. Zhao
A multi-task learning (MTL) framework, called gradient kernel ridge regression, for nuclear masses and separation energies is developed by introducing gradient kernel functions to the kernel ridge regression (KRR) approach. By taking the WS4 mass model as an example, the gradient KRR network is trained with the mass model residuals, i.e., deviations between experimental and theoretical values of masses and one-nucleon separation energies, to improve the accuracy of theoretical predictions. Significant improvements are achieved by the gradient KRR approach in both the interpolation and the extrapolation predictions of nuclear masses and separation energies. This demonstrates the advantage of the present MTL framework that integrates the information of nuclear masses and separation energies and improves the predictions for both of them.
nucl-thPLB(2022)·51 citations
03
Neutrino propagation in the neutron star with uncertainties from nuclear, hadron, and particle physics
Parada T. P. Hutauruk🇰🇷 · Hana Gil🇰🇷 · Seung-il Nam🇰🇷 · Chang Ho Hyun🇰🇷
In the present work, we investigate the neutral-current neutrino-nucleon scattering in the nuclear medium using various energy-density functional (EDF) models such as the KIDS (Korea-IBS-Daegu-SKKU) and SLy4, together with the quark-meson coupling (QMC) model for the nucleon form factors at finite density. The differential cross section (DCS) and neutrino mean free path (NMFP) are computed numerically, considering the density-dependent nucleon form factors (DDFF) and neutrino structural properties such as the neutrino magnetic moment (NMM) and its electric charge radius (NCR). It turns out that the DDFF decreases the scattering cross-section, while the NCR increases it considerably. The effect of the NMM turns out to be almost negligible. We also observe that the value of the neutron effective mass is of importance in the neutron-star cooling process, indicating that for the neutron effective mass larger than the mass in free space, the neutrino can interact with matter at densities $ρ ≳ 1.5 ρ_{0}$ in the neutron star with radius 13 km.
nucl-thastro-ph.HEastro-ph.SRhep-phPTEP(2023)·2 citations
04
Partonic Critical Opalescence and Its Impact on the Jet Quenching Parameter $q^$
Jing Wu🇨🇳 · Shanshan Cao🇨🇳 · Feng Li🇨🇳
Jet quenching parameter $q^$ is essential for characterizing the interaction strength between jet partons and nuclear matter. Based on the quark-meson (QM) model, we develop a new framework for calculating $q^$ at finite chemical potentials, in which $q^$ is related to the spectral function of the chiral order parameter. A perturbative calculation up to the one-loop order indicates that the momentum broadening of jets is enhanced at both the high temperature and high chemical potential, and approximately proportional to the parton number density in the partonic phase. We further investigate the behavior of $q^$ in the vicinity of the critical endpoint (CEP) by coupling our calculation with a recently developed equation of state that includes a CEP in the universality class of the Ising model, from which we discover the partonic critical opalescence (PCO) -- a prominent enhancement of the momentum broadening of jets near CEP, contributed by the scatterings via the $σ$ exchange process. Hence, for the first time, jet quenching is connected with the search of CEP.
nucl-thChin.Phys.Lett.(2024)·11 citations
05
Back-to-back inclusive dijets in DIS at small $x$ : Sudakov suppression and gluon saturation at NLO
Paul Caucal🇺🇸 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸 · Raju Venugopalan🇺🇸
Back-to-back dijet cross-sections in deeply inelastic scattering (DIS) at small $x_{Bj}$ are suppressed by many-body multiple scattering and screening effects arising from gluon saturation at high parton densities. They are similarly sensitive in these kinematics to large Sudakov logarithms from soft gluon radiation. Uncovering novel physics in this DIS channel therefore requires understanding the interplay of the two phenomena. In this work, we compute the small $x_{Bj}$ inclusive dijet DIS cross-section in back-to-back kinematics at next-to-leading order (NLO) in the Color Glass Condensate effective field theory (CGC EFT). Our result includes, for the first time, all real and virtual NLO contributions to the impact factor. These include all Sudakov double and single logarithm contributions, as well as all other finite $O (α_{s})$ terms that contribute at this order. We demonstrate explicitly that resummations of small $x$ and Sudakov logarithms can be performed simultaneously in the CGC EFT. This requires that the JIMWLK kernel for small $x$ evolution of the Weizsäcker-Williams (WW) gluon distribution satisfies a kinematic constraint imposed by lifetime ordering of successive gluon emissions; the corresponding modifications to the kernel, corresponding to resummations of large double transverse logarithms, are precisely of the type required to stabilize JIMWLK evolution beyond leading logarithmic accuracy. We compute the azimuthal harmonics of the NLO back-to-back distributions and show their sensitivity to both the unpolarized and linearly polarized WW gluon distributions. Finally, we discuss how TMD factorization is broken by an emergent saturation scale at small $x$ .
↳ hep-phhep-thnucl-thJHEP(2022)·88 citations
06
Bethe-Salpeter kernel and properties of strange-quark mesons
Zhen-Ni Xu🇨🇳 · Zhao-Qian Yao🇨🇳 · Si-Xue Qin🇨🇳 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳
Focusing on the continuum meson bound-state problem, a novel method is used to calculate closed-form Bethe-Salpeter kernels that are symmetry consistent with any reasonable gluon-quark vertex, $Γ_{ν}$ , and therewith deliver a Poincaré-invariant treatment of the spectrum and decay constants of the ground- and first-excited states of $u$ , $d$ , $s$ mesons. The predictions include masses of as-yet unseen states and many unmeasured decay constants. The analysis reveals that a realistic, unified description of meson properties (including level orderings and mass splittings) requires a sound expression of emergent hadron mass in bound-state kernels; alternatively, that such properties may reveal much about the emergence of mass in the standard model.
↳ hep-phhep-exhep-latnucl-ex+1EPJA(2023)·33 citations
07
Estimation of compositeness with correction terms
Tomona Kinugawa🇯🇵 · Tetsuo Hyodo🇯🇵
The compositeness $X$ is defined as the probability to observe the composite structure such as the hadronic molecule component in a bound state. One of the model-independent approaches to calculate $X$ is the weak-binding relation. However, when the scattering length $a_{0}$ is larger than the radius of the bound state $R$ , the central value of the compositeness $X$ becomes larger than unity, which cannot be interpreted as a probability. For the systems with $a_{0} > R$ , we need to estimate the compositeness with the correction terms. For the reasonable determination of the compositeness, we first present the quantitative estimation of the correction terms. Because the exact value of the compositeness should be contained in its definition domain $0 \leq X \leq 1$ , we propose the reasonable estimation method with the uncertainty band by excluding the region outside of the definition domain of the compositeness. We finally estimate the compositeness of physical systems, and obtain the result which we can interpret as the fraction of the composite component.
↳ hep-phnucl-thEPJ Web Conf.(2022)·0 citations
08
Analysis of coupled-channel potentials with quark and hadron degrees of freedom
Ibuki Terashima🇯🇵 · Tetsuo Hyodo🇯🇵
The quark-antiquark potentials are known to be confining in the absence of the $q ˉ q$ pair creation. On the other hand, the inter-hadron potentials vanish at large distance, because the interaction range is limited by the inverse pion mass. When the $q ˉ q$ pair creation and annihilation are switched on, the channel coupling occurs between the quark and hadron degrees of freedom, modifying the behavior of potentials. In this work, we investigate the properties of the effective potentials obtained by eliminating one of the channels. We show that the coupling to the eliminated channel induces a non-local and energy dependent effective potential, irrespective of the properties of the transition potential. In addition, when the hadron channel having continuous scattering eigenstates is eliminated, the resulting inter-quark potential contains an imaginary part above the threshold to describe the decay effect into the meson pair.
↳ hep-phnucl-thEPJ Web Conf.(2022)·1 citation
09
Global constraint on the jet transport coefficient from single hadron, dihadron and $γ$ -hadron spectra in high-energy heavy-ion collisions
Man Xie🇨🇳 · Weiyao Ke🇺🇸 · Hanzhong Zhang🇨🇳 · Xin-Nian Wang🇺🇸
Modifications of large transverse momentum single hadron, dihadron, and $γ$ -hadron spectra in relativistic heavy-ion collisions are direct consequences of parton-medium interactions in the quark-gluon plasma (QGP). The interaction strength and underlying dynamics can be quantified by the jet transport coefficient $q^$ . We carry out the first global constraint on $q^$ using a next-to-leading order pQCD parton model with higher-twist parton energy loss and combining world experimental data on single hadron, dihadron, and $γ$ -hadron suppression at both RHIC and LHC energies with a wide range of centralities. The global Bayesian analysis using the information field (IF) priors provides the most stringent constraint on $q^(T)$ . We demonstrate in particular the progressive constraining power of the IF Bayesian analysis on the strong temperature dependence of $q^$ using data from different centralities and colliding energies. We also discuss the advantage of using both inclusive and correlation observables with different geometric biases. As a verification, the obtained $q^(T)$ is shown to describe data on single hadron anisotropy at high transverse momentum well. Predictions for future jet quenching measurements in oxygen-oxygen collisions are also provided.
↳ hep-phnucl-thPRC(2024)·34 citations
10
Hyperon bulk viscosity and $r$ -modes of neutron stars
O. P. Jyothilakshmi🇮🇳 · P. E. Sravan Krishnan🇮🇳 · Prashant Thakur🇮🇳 · V. Sreekanth🇮🇳 · T. K. Jha🇮🇳
We propose and apply a new parameterization of the modified chiral effective model to study rotating neutron stars with hyperon cores in the framework of the relativistic mean-field theory. The inclusion of mesonic cross couplings in the model has improved the density content of the symmetry energy slope parameters, which are in agreement with the findings from recent terrestrial experiments. The bulk viscosity of the hyperonic medium is analyzed to investigate its role in the suppression of gravitationally driven $r$ -modes. The hyperonic bulk viscosity coefficient caused by non-leptonic weak interactions and the corresponding damping timescales are calculated and the $r$ -mode instability windows are obtained. The present model predicts a significant reduction of the unstable region due to a more effective damping of oscillations. We find that from $\sim 1 0^{8}$ K to $\sim 1 0^{9}$ K, hyperonic bulk viscosity completely suppresses the $r$ -modes leading to a stable region between the instability windows. Our analysis indicates that the instability can reduce the angular velocity of the star up to $\sim$ 0.3~ $Ω_{K}$ , where $Ω_{K}$ is the Kepler frequency of the star.
↳ astro-ph.HEhep-phnucl-thMNRAS(2022)·21 citations

Affiliations

first authorsco-authorsvia INSPIRE