Nuclear Theory·nucl-th

Tuesday·November 2, 2021

15 papers—7 primary·8 cross-listed

08
Godunov variables and convex entropy for relativistic fluid dynamics with bulk viscosity
Heiner Olbermann
Based on the conservation-dissipation formalism proposed by Zhu and collaborators we formulate a general version of the Israel-Stewart theory for relativistic fluid dynamics with bulk viscosity. Our generalization consists in allowing for a wide range of dependence of the entropy density on the bulk viscosity. We show the existence of Godunov-Boillat variables for this model. By known properties of systems possessing such variables, this provides an alternative proof of the recently established existence of solutions for the Israel-Stewart theory locally in time, and a proof that entropy production is positive across weak Lax shocks.
↳ math.APnucl-thJ.Math.Phys.(2022)·0 citations
09
Radial oscillations of quark stars admixed with dark matter
José C. Jiménez🇧🇷 · Eduardo S. Fraga🇧🇷
We investigated compact stars consisting of cold quark matter and fermionic dark matter treated as two admixed fluids. We computed the stellar structures and fundamental radial oscillation frequencies for different masses of the dark fermion in the cases of weak and strong self-interacting dark matter. We found that the fundamental frequency can be dramatically modified and, in some cases, stable dark strange planets and dark strangelets with very low masses and radii can be formed.
↳ hep-phastro-ph.HEgr-qcnucl-thUniverse(2022)·30 citations
10
Gliding down the QCD transition line, from $N_{f} = 2$ till the onset of conformality
A.Yu. Kotov (Fachhochsch., Julich and Dubna, JINR)🇩🇪 · M.P. Lombardo (INFN, Florence)🇮🇹 · A. Trunin (Samara U.)🇷🇺
We review the hot QCD transition with varying number of flavors, from two till the onset of the conformal window. We discuss the universality class for $N_{f} = 2$ , along the critical line for two massless light flavors, and a third flavor whose mass serves as an interpolator between $N_{f} = 2$ and $N_{f} = 3$ . We identify a possible scaling window for the 3D $O (4)$ universality class transition, and its crossover to a mean field behaviour. We follow the transition from $N_{f} = 3$ to larger $N_{f}$ , when it remains of first order, with an increasing coupling strength; we summarize its known properties, including possible cosmological applications as a model for a strong electroweak transition. The first order transition, and its accompanying second order endpoint, finally morphs into the essential singularity at the onset of the conformal window, following the singular behaviour predicted by the Functional Renormalization Group.
↳ hep-lathep-phhep-thnucl-thSymmetry(2021)·18 citations
11
H2ZIXY: Pauli spin matrix decomposition of real symmetric matrices
Rocco Monteiro Nunes Pesce🇬🇧 · Paul D. Stevenson🇬🇧
We present a code in Python3 which takes a square real symmetric matrix, of arbitrary size, and decomposes it as a tensor product of Pauli spin matrices. The application to the decomposition of a Hamiltonian of relevance to nuclear physics for implementation on quantum computer is given.
↳ physics.comp-phnucl-thquant-ph16 citations
12
Dissipative superfluid relativistic magnetohydrodynamics of a multicomponent fluid: the combined effect of particle diffusion and vortices
Vasiliy A. Dommes · Mikhail E. Gusakov
We formulate dissipative magnetohydrodynamic equations for finite-temperature superfluid and superconducting charged relativistic mixtures, taking into account the effects of particle diffusion and possible presence of Feynman-Onsager and/or Abrikosov vortices in the system. The equations depend on a number of phenomenological transport coefficients, which describe, in particular, relative motions of different particle species and their interaction with vortices. We demonstrate how to relate these transport coefficients to the mutual friction parameters and momentum transfer rates arising in the microscopic theory. The resulting equations can be used to study, in a unified and coherent way, a very wide range of phenomena associated with dynamical processes in neutron stars, e.g., the magnetothermal evolution, stellar oscillations and damping, as well as development and suppression of various hydrodynamic instabilities in neutron stars.
↳ astro-ph.HEgr-qcnucl-thPRD(2021)·10 citations
13
Complementarity between neutrinoless double beta decay and collider searches for heavy neutrinos in composite-fermion models
S. Biondini🇨🇭 · S. Dell'Oro🇮🇹 · R. Leonardi🇮🇹 · S. Marcocci🇺🇸 · O. Panella🇮🇹 · M. Presilla🇮🇹 · F. Vissani🇮🇹
Composite-fermion models predict excited quarks and leptons with mass scales which can potentially be observed at high-energy colliders like the LHC; the most recent exclusion limits from the CMS and ATLAS Collaborations corner excited-fermion masses and the compositeness scale to the multi-TeV range. At the same time, hypothetical composite Majorana neutrinos would lead to observable effects in neutrinoless double beta decay ( $0 ν β β$ ) experiments. In this work, we show that the current composite-neutrino exclusion limit $M_{N} > 4.6$ TeV, as extracted from direct searches at the LHC, can indeed be further improved to $M_{N} > 8.8$ TeV by including the bound on the nuclear transition $^{136}$ Xe $\to$ $^{136}$ Ba $+ 2 e^{-}$ . Looking ahead, the forthcoming HL-LHC will allow probing a larger portion of the parameter-space, nevertheless, it will still benefit from the complementary limit provided by $0 ν β β$ future detectors to explore composite-neutrino masses up to $12.6$ TeV.
↳ hep-phnucl-exnucl-th4 citations
14
Asymptotics of transverse momentum broadening in dense QCD media
Paul Caucal🇺🇸
We study the asymptotic behaviour of the transverse momentum broadening distribution of an energetic quark or gluon propagating through dense QCD matter, in the large system size $L$ limit, taking into account radiative corrections in the double logarithmic approximation. Thanks to a connection between the evolution of the jet quenching parameter $q^$ and the formation of traveling wave fronts in nonlinear physics, we obtain a formula for the $L$ dependence of the characteristic transverse momentum scale $Q_{s}$ of the distribution valid up to terms of order $1/ ln (L)$ . We briefly discuss the physical implications of this formula for jet quenching and small- $x$ phenomenology.
↳ hep-phnucl-thSciPost Phys.Proc.(2022)·0 citations
15
Connecting Matrix Elements to Multi-Hadron Form-Factors
Andrew W. Jackura🇺🇸
We discuss developments in calculating multi-hadron form-factors and transition processes via lattice QCD. Our primary tools are finite-volume scaling relations, which map spectra and matrix elements to the corresponding multi-hadron infinite-volume amplitudes. We focus on two hadron processes probed by an external current, and provide various checks on the finite-volume formalism in the limiting cases of perturbative interactions and systems forming a bound state. By studying model-independent properties of the infinite-volume amplitudes, we are able to rigorously define form-factors of resonances.
↳ hep-lathep-phnucl-thPoS(2022)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE