Nuclear Theory·nucl-th

Friday·January 5, 2024

9 papers—2 primary·7 cross-listed

01
Pseudospin Symmetry: Microscopic origin of the ground-state inversion in neutron-rich odd-A Cu isotopes
Tianshuai Shang · Jian Li · Qiang Zhao
The role of the pseudospin symmetry in the inversion of the ground-state spin in Cu isotopes is investigated within the covariant density functional theory (CDFT). The density functional PC-PK1 gives a good agreement with the observed ground-state properties of the odd-A $^{69 - 79}$ Cu. In particular, the inversion of the ground-state spin at $A = 75$ is reproduced nicely, which can be explained by the level crossing between the proton pseudospin partners $π 2 p_{3/2}$ and $π 1 f_{5/2}$ . It is found that the pseudospin symmetry plays a dominant role in the evolution of the energy splittings between the pseudospin partners. By comparing with the results of the nonrelativistic DFTs, our studies suggest that the pseudospin symmetry is essential to the shell evolution around this region.
nucl-thPLB(2024)·8 citations
02
Shear viscosity of nucleonic matter
Xian-Gai Deng🇨🇳 · De-Qing Fang🇨🇳 · Yu-Gang Ma🇨🇳
The research status of the shear viscosity of nucleonic matter is reviewed. Some methods to calculate the shear viscosity of nucleonic matter are introduced, including mean free path, Green-Kubo, shear strain rate, Chapman-Enskog and relaxation time approximation. Based on these methods, results for infinite and finite nucleonic matter are discussed, which are attempts to investigate the universality of the ratio of shear viscosity over entropy density and transport characteristics like the liquid-gas phase transition in nucleonic matter. In addition, shear viscosity is also briefly discussed for the quantum chrodynamical matter produced in relativistic heavy-ion collisions.
nucl-thnucl-exPPNP(2024)·24 citations
03
Semi-inclusive single-jet production in DIS at next-to-leading order in the Color Glass Condensate
Paul Caucal🇫🇷 · Elouan Ferrand🇫🇷 · Farid Salazar🇺🇸
Within the Color Glass Condensate (CGC) effective field theory, we derive the next-to-leading order (NLO) cross-section for the single-jet semi-inclusive cross-section in deep inelastic scattering (DIS) at small $x$ , for both longitudinally and transversely polarized virtual photons. We provide analytic expressions, valid at finite $N_{c}$ and suitable for numerical evaluation, for both the cross-section differential in rapidity and transverse momentum and the cross-section differential in rapidity only. Our NLO formulae demonstrate that the very forward rapidity regime is plagued by large double logarithmic corrections coming from phase space constraints on soft gluons close to the kinematic threshold for jet production. A joint resummation of small- $x$ and threshold logarithms at single logarithmic accuracy is proposed to remedy the instability of the cross-section in this regime. By integrating over the single-jet phase space, we recover known results for the NLO DIS structure functions at small $x$ , previously obtained using the optical theorem.
↳ hep-phnucl-thJHEP(2024)·27 citations
04
The DIS 1-Jettiness Event Shape at N $^{3}$ LL+ $O (α_{s}^{2})$
Haotian Cao🇨🇳 · Zhong-Bo Kang🇺🇸 · Xiaohui Liu🇨🇳 · Sonny Mantry🇺🇸
We present results for the $τ_{1}$ and $τ_{1 a}$ 1-Jettiness global event shape distributions, for Deep Inelastic Scattering (DIS), at the N $^{3}$ LL + $O (α_{s}^{2})$ level of accuracy. These event-shape distributions quantify and characterize the pattern of final state radiation in electron-nucleus collisions. They can be used as a probe of nuclear structure functions, nuclear medium effects in jet production, and for a precision extraction of the QCD strong coupling. The results presented here, along with the corresponding numerical codes, can be used for analyses with HERA data, in EIC simulation studies, and for eventual comparison with real EIC data.
↳ hep-phhep-exnucl-thPRD(2024)·15 citations
05
Dark Matter Influence on Quarkyonic Stars: A Relativistic Mean Field Analysis
D. Dey🇮🇳 · Jeet Amrit Pattnaik🇮🇳 · H. C. Das🇮🇹 · A. Kumar🇨🇳 · R. N. Panda🇮🇳 · S. K. Patra🇮🇳
The formulation of quarkyonic matter consists of treating both quarks and nucleons as quasi-particles, where a cross-over transition occurs between the two phases. This work is based upon some of the early ideas of quark matter. It can satisfy the different observational constraints on the neutron star (NS), such as its maximum mass and the canonical radius. In addition, we put an extra component inside the NS known as Dark Matter (DM) because it is trapped due to its immense gravitational potential. In this work, we explore the impact of fermionic DM on the structure of the NS. The equation of state (EOS) is derived for the NS with the quarkyonic matter by assuming that nucleons and quarks are in equilibrium, followed by the relativistic mean-field (RMF) formalism. The recently modeled two parameterizations, such as G3 and IOPB-I, are taken to calculate the various macroscopic properties of the NS. The three unknown parameters such as the transition density ( $n_{t}$ ), the QCD confinement scale ( $Λ_{sc}$ ), and the DM Fermi momentum ( $k_{f}^{DM}$ ) are varied to obtain the NS properties. The quarkyonic matter stiffens the EOS while DM softens it. The mutual combination provides us with good theoretical predictions for the magnitude of macroscopic properties consistent with the different observational results. Also, one can estimate the parameters of the DM admixed quarkyonic star with different statistical analyses, which can be further used to explore the other properties of the quarkyonic star.
↳ astro-ph.HEnucl-thJCAP(2025)·13 citations
06
Hybrid star models in the light of new multi-messenger data
Jia Jie Li (SWU, Chongqing)🇧🇬 · Armen Sedrakian (FIAS Frankfurt and U. Wroclaw)🇩🇪 · Mark Alford (Washington U., St. Louis)🇺🇸
Recent astrophysical mass inferences of compact stars HESS J1731-347 and PSR J0952-0607, with extremely small and large masses respectively, as well as the measurement of the neutron skin of Ca in the CREX experiment challenge and constrain the models of dense matter. We examine the concept of hybrid stars - objects containing quark cores surrounded by nucleonic envelopes - as models that account for these new data along with other inferences. We employ a family of 81 nucleonic equations of state (EoSs) with variable skewness and slope of symmetry energy at saturation density and a constant speed-of-sound EoS for quark matter. For each nucleonic EoS, a family of hybrid EoSs is generated by varying the transition density, the energy jump, and the speed of sound. These models are tested against the data from GW170817 and J1731-347, which favor low-density soft EoS and J0592-0607 and J0740+6620, which require high-density stiff EoS. The addition of J0592-0607's mass measurement to the constraints has no significant impact on the parameter space of the admissible EoS, but allows us to explore the potential effect of pulsars more massive than J0740+6620, if such exists. We then examine the occurrence of twin configurations and quantify the ranges of masses and radii that they can possess. It is shown that including J1731-347 data favors EoSs that predict low-mass twins with $M ≲ 1.3 M_{⊙}$ that can be realized if the deconfinement transition density is low. If combined with large speed of sound in quark matter such models allow for maximum masses of hybrid stars in $2.0$ -- $2.6 M_{⊙}$ .
↳ astro-ph.HEhep-phnucl-thApJ(2024)·37 citations
07
Hydrodynamic Simulations of Oxygen-Neon Classical Novae as Galactic $^{7}$ Li Producers and Potential Accretion Induced Collapse Progenitors
Sumner Starrfield · Maitrayee Bose · Christian Iliadis · W. Raphael Hix · Charles E. Woodward · R. Mark Wagner
We report on studies of Classical Nova (CN) explosions where we follow the evolution of thermonuclear runaways (TNRs) on oxygen-neon (ONe) white dwarfs (WDs). Using NOVA, a one-dimensional hydrodynamic computer code, we accrete Solar matter until the TNR is ongoing and then switch to a mixed composition. This approach is guided by the results of multi-dimensional studies of TNRs in WDs which find that sufficient mixing with WD core material occurs after the TNR is well underway, and levels of enrichment of the CNONeMg elements are reached that agree with observations of CN ejecta abundances. Because the amount of accreted material is inversely proportional to the oxygen abundance, by first accreting Solar matter, the amount of accreted material is larger than in those simulations with an initially enriched composition. We vary the mass of the WD (from 0.6 Msun to 1.35 Msun) and the composition of the mixed materials. Our results show large enrichments of 7Be in the ejected gases implying that ONe CNe and CO CNe (Starrfield et al. 2020) may be responsible for a significant fraction (about 100 Msun) of the galactic 7Li ( about 1000 Msun). The production of 22Na and 26Al in CN explosions and the gamma-ray emission predicted by our simulations is discussed. The WDs in all our simulations eject less material than they accrete and we predict that the WD is growing in mass as a consequence of the CN outburst. ONe CNe, therefore, may be an important channel for accretion induced collapse (AIC) events.
↳ astro-ph.SRastro-ph.HEnucl-thApJ(2024)·9 citations
08
Towards the determination of the 3-dimensional structure of the proton using lattice QCD simulations
Constantia Alexandrou (Univ. of Cyprus & The Cyprus inst.)🇨🇾 · Simone Bacchio (The Cyprus Inst.)🇨🇾
State-of-the-art lattice QCD simulations enable the evaluation of nucleon form factors and Mellin moments with controlled systematics, yielding results with unprecedented accuracy. At the same time, new theoretical approaches are allowing the direct computation of nucleon generalized parton distributions. We review recent lattice QCD results on these quantities that are paving the way for extracting a wealth of information on the 3-dimensional structure of the nucleon.
↳ hep-latnucl-exnucl-th0 citations
09
Updated numerical study of transverse single-spin asymmetries in single-inclusive pion production from lepton-nucleon collisions
Sophia Fitzgibbons🇺🇸 · Michel Malda🇺🇸 · Jacob Marsh🇺🇸 · Daniel Pitonyak🇺🇸 · Penn Smith🇺🇸
We revisit the analysis of transverse single-spin asymmetries $A_{N}$ in lepton-nucleon scattering where only a single pion is detected in the final state, $ℓ N^{↑} \to h X$ . This observable is the Electron-Ion Collider (EIC) analogue to $A_{N}$ in proton-proton collisions, $p^{↑} p \to h X$ , that has been studied intensely for decades, especially at the Relativistic Heavy Ion Collider (RHIC). We incorporate new theoretical developments in the collinear twist-3 framework and utilize recent extractions of (Sivers-like and Collins-like) quark-gluon-quark correlators in the numerical computations. We compare our calculations to HERMES measurements as well as make predictions for Jefferson Lab, COMPASS, and EIC kinematics. We further explore the role of next-to-leading order (NLO) corrections to the (twist-2) unpolarized cross section (denominator of $A_{N}$ ) and consider what can be deduced empirically about the potential numerical significance of the full NLO calculation of $A_{N}$ in this process. We consider sources of theoretical uncertainty in our predictions, which present potential opportunities then for future measurements to improve our understanding of $A_{N}$ and multi-parton correlations in hadrons.
↳ hep-phhep-exnucl-exnucl-thPLB(2024)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE