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Nuclear Theory·nucl-th

Monday·August 1, 2022

7 papers—2 primary·5 cross-listed

All7Primary2Cross-lists5
  1. 03

    Crystallization in single and multicomponent Neutron Star crusts

    D. Barba-González · C. Albertus · M. Ángeles Pérez-García

    We use Molecular Dynamics simulations to study the formation and stability of single and multicomponent lattices in the outer crust of Neutron Stars. Including an improved treatment for Gaussian charge distributions of ions we obtain the expressions for the potential and forces arising from electron screened Coulomb interactions using the efficient Ewald sum procedure. %in the plasma. Our findings show that for baryon densities in the outer crust a point-like ion treatment can not fully describe the crystallization behaviour thus the Coulomb parameter, , along with the usual screening parameter, , due to charge neutralizing electron polarizable background, must be complemented with an additional parameter, , providing information on the finite size of ions. In our approach we find that including beyond point-like approaches in screened plasmas has a robust impact on calculated lattice energetic stability decreasing crystallization energies per baryon up to with respect to point-like interaction and, as a consequence, melting point resulting displaced to lower temperatures.

    ↳ astro-ph.HEnucl-thphysics.plasm-phPRC(2022)·10 citations
  2. 04

    Neutron star crust in Voigt approximation II: general formula for electron screening correction for effective shear modulus

    Andrey I. Chugunov (Ioffe Institute)

    The main contribution to the effective shear modulus of neutron star crust can be calculated within Coulomb solid model and can be approximated by simple analytical expression for arbitrary (even multicomponent) composition. Here I consider correction associated with electron screening within Thomas-Fermi approximation. In particular, I demonstrate that for relativistic electrons (density g\,cm) this correction can be estimated as , where summation is taken over ion species, is number density of ions with charge , is Thomas-Fermi screening wave number. Finally, is electron sphere radius. Quasineutrality condition is assumed. This result holds true for arbitrary (even multicomponent and amorphous) matter and can be applied for neutron star crust and (dense) cores of white dwarfs. For example, the screening correction reduces shear modulus by \% for , which is typical for inner layers of neutron star crust.

    ↳ astro-ph.HEcond-mat.mtrl-scinucl-thphysics.plasm-phMNRAS(2022)·5 citations
  3. 05

    Pion spectral properties above the chiral crossover of QCD

    Peter Lowdon🇩🇪 · Owe Philipsen🇩🇪

    Spectral functions encode a wealth of information about the dynamics of any given system, and the determination of their non-perturbative characteristics is a long-standing problem in quantum field theory. Whilst numerical simulations of lattice QCD provide ample data for various Euclidean correlation functions, the inversion required to extract spectral functions is an ill-posed problem. In this work, we pursue previously established constraints imposed by field locality at finite temperature , namely that spectral functions possess a non-perturbative representation which generalises the well-known Källén-Lehmann spectral form to . Using this representation, we analyse lattice QCD data of the spatial pseudo-scalar correlator in the temperature range , and obtain an analytic expression for the corresponding spectral function, with parameters fixed by the data. From the structure of this spectral function we find evidence for the existence of a distinct pion state above the chiral pseudo-critical temperature , and contributions from its first excitation, which gradually melt as the temperature increases. As a non-trivial test, we find that the extracted spectral function reproduces the corresponding temporal lattice correlator data for .

    ↳ hep-lathep-phhep-thnucl-thJHEP(2022)·41 citations
  4. 06

    Bayesian quantification of the Quark-Gluon Plasma: Improved design and closure demonstration

    Matthew Heffernan🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦 · Jean-Francois Paquet🇺🇸

    We present a demonstration of the design sampling and closure for the first comprehensive Bayesian model-to-data comparison of heavy-ion measurements with IP-Glasma initial conditions, in which we combine with state-of-the-art hydrodynamics (MUSIC), particlization (iS3D), and transport (SMASH). We further introduce a systematically-improvable method of sampling design points with better projection properties to explore the parameter space of the model for the first time in heavy-ion collisions.

    ↳ hep-phnucl-thActa Phys.Polon.Supp.(2023)·4 citations
  5. 07

    Improved background subtraction and a fresh look at jet sub-structure in JEWEL

    José Guilherme Milhano🇵🇹 · Korinna Zapp🇸🇪

    Interactions of hard partons in the Quark Gluon Plasma (QGP) created with relativistic heavy ion collisions lead to characteristic modifications of the internal structure of reconstructed jets. A large part of the observed jet sub-structure modifications stem from the QGP's response to energy and momentum deposited by hard partons. Good control over medium response in theoretical calculations is thus instrumental to a quantitative understanding of medium modified (quenched) jets in heavy ion collisions. We present an improved way of handling the medium response in the jet quenching model JEWEL and present results for a variety of jet sub-structure observables. The new recoil handling is more versatile and robust than the old scheme, giving a better control over many observables and, in particular, greatly improves the description of the jet mass.

    ↳ hep-phnucl-exnucl-thEPJC(2022)·33 citations

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