Nuclear Theory·nucl-th

Wednesday·February 16, 2022

8 papers—4 primary·4 cross-listed

05
[Submitted on 15 Feb 2022] (cross-list from hep-ph)
Landau quantization and spin polarization of cold magnetized quark matter
Zhen-Yan Lu🇨🇳 · Jian-Feng Xu🇨🇳 · Xin-Jian Wen🇨🇳 · Guang-Xiong Peng🇨🇳 · Marco Ruggieri🇨🇳
The magnetic field and density behaviors of various thermodynamic quantities of strange quark matter under compact star conditions are investigated in the framework of the thermodynamically self-consistent quasiparticle model. For individual species, a larger number density $n_{i}$ leads to a larger magnetic field strength threshold that align all particles parallel or antiparallel to the magnetic field. Accordingly, in contrast to the finite baryon density effect which reduces the spin polarization of magnetized strange quark matter, the magnetic field effect leads to an enhancement of it. We also compute the sound velocity as a function of the baryon density and find the sound velocity shows an obvious oscillation with increasing density. Except for the oscillation, similar to the zero-magnetic field case that the sound velocity grows with increasing density and approaches the conformal limit $V_{s}^{2} = 1/3$ at high densities from below.
Comments:
10 pages, 7 figures; Manuscript has been accepted for publication as a Regular Article in Chinese Physics C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2202.07197 [pdf]
CPC(2022)·7 citations
06
[Submitted on 15 Feb 2022] (cross-list from hep-ph)
Linear mode analysis from spin transport equation
Jin Hu🇨🇳
We provide a linear analysis on normal modes of the spin Boltzmann equation proposed in \cite{Weickgenannt:2021cuo}, where the non-diagonal or polarized part of the transition rate is neglected to ensure the Hermitian property of linearized collision operator. As an instrumental element of spin kinetic theory, the conservation of total angular momentum is explicitly considered, thus our analysis is relevant to the recent investigation on the issue of local spin polarization. By treating the linearized collision operator as an evolution operator, solving the normal modes turns out a degenerate perturbation problem in quantum mechanics. The dispersion relations of spinless modes are in accordance with well-known calculations, while the frequencies of spin modes are also determined up to second-order in wave vector and the second order expressions are only formal solutions to be further determined. Moreover, the relaxation of spin density is related to our linear mode analysis, which shall play a big role in investigating the issues of the local spin polarization in the relativistic heavy-ion collisions.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2202.07373 [pdf]
PRD(2022)·29 citations
07
[Submitted on 15 Feb 2022] (cross-list from cond-mat.quant-gas)
Fundamental limitations of the eigenvalue continuation approach
Tomasz Sowiński🇵🇱 · Miguel A. Garcia-March🇪🇸
In this work, we show that the eigenvalue continuation approach introduced recently in [Phys. Rev. Lett. {\bf 121}, 032501 (2018)], despite its many advantages, has some fundamental limitations which cannot be overcome when strongly correlated many-body systems are considered. Taking as a working example a very simple system of several fermionic particles confined in a harmonic trap we show that the eigenvector continuation is not able to go beyond the accuracy of the sampling states. We support this observation within a very simple three-level model capturing directly this obstacle. Since mentioned inaccuracy cannot be determined self-consistently within the eigenvalue continuation approach, support from other complementary methods is needed.
Comments:
Authors' version accepted for publication
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2202.07493 [pdf]
PRC(2022)·4 citations
08
[Submitted on 15 Feb 2022] (cross-list from hep-ph)
Tau longitudinal and transverse polarizations from visible kinematics in (anti-)neutrino nucleus scattering
E. Hernández🇪🇸 · J. Nieves🇪🇸 · F. Sánchez🇨🇭 · J. E. Sobczyk🇩🇪
Since the $ν_{τ} (ν ˉ_{τ}) A_{Z} \to τ^{\mp} X$ reaction is notoriously difficult to be directly measured, the information on the dynamics of this nuclear process should be extracted from the analysis of the energy and angular distributions of the tau decay visible products. These distributions depend on the components of the tau-polarization vector. We give, for the first time, the general expression for the outgoing hadron (pion or rho meson) energy and angular differential cross section for the sequential $ν_{τ} A_{Z} \to τ^{-} (π^{-} ν_{τ}, ρ^{-} ν_{τ}) X$ and $ν ˉ_{τ} A_{Z} \to τ^{+} (π^{+} ν ˉ_{τ}, ρ^{+} ν ˉ_{τ}) X$ reactions. Though all possible nuclear reaction mechanisms contribute to the distribution, it may be possible to isolate/enhance one of them by implementing appropriate selection criteria. For the case of the quasi-elastic reaction off oxygen and neutrino energies below 6 GeV, we show that the pion distributions are sensitive to the details of the tau-polarization components. We find significant differences between the full calculation, where the longitudinal and transverse components of the tau polarization vector vary with the energy and the scattering angle of the produced tau, and the simplified scheme in which the polarizations are set to one and zero (respective asymptotic values in the high energy regime). In addition to its potential impact on neutrino oscillation analyses, this result can be used to further test different nuclear models, since these observables provide complementary information to that obtained by means of the inclusive nuclear weak charged-current differential cross section. We also study the effects on the cross section of the $W_{4}$ , $W_{5}$ nuclear structure functions, which contributions are proportional to the charged lepton mass, and therefore difficult to constrain in muon and electron neutrino experiments.
Comments:
11 pages, 5 figures. We have corrected a numerical error in our calculation. Figures have changed but the discussion and conclusions remain the same. An erratum will be published
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2202.07539 [pdf]
PLB(2022)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE

Landau quantization and spin polarization of cold magnetized quark matter

Linear mode analysis from spin transport equation

Fundamental limitations of the eigenvalue continuation approach

Tau longitudinal and transverse polarizations from visible kinematics in (anti-)neutrino nucleus scattering

Affiliations