Nuclear Theory·nucl-th

Wednesday·June 26, 2024

7 papers—4 primary·3 cross-listed

01
[Submitted on 25 Jun 2024]
Hybrid isentropic twin stars
Juan Pablo Carlomagno · Gustavo A. Contrera · Ana Gabriela Grunfeld · David Blaschke
We present a study of hybrid neutron stars with color superconducting quark matter cores at finite temperature that results in sequences of stars with constant entropy per baryon, $s / n_{B} = const$ . For the quark matter equation of state, we employ a recently developed nonlocal chiral quark model while nuclear matter is described with a relativistic density functional model of the DD2 class. The phase transition is obtained by a Maxwell construction under isothermal conditions. We find that traversing the mixed phase on a trajectory at low $s / n_{B} ≲ 2$ in the phase diagram shows a heating effect while at larger $s / n_{B}$ the temperature drops. This behavior may be attributed to the presence of a color superconducting quark matter phase at low temperatures and the melting of the diquark condensate which restores the normal quark matter phase at higher temperatures. While the isentropic hybrid star branch at low $s / n_{B} ≲ 2$ is connected to the neutron star branch, it gets disconnected at higher entropy per baryon so that the "thermal twin" phenomenon is observed. We find that the transition from connected to disconnected hybrid star sequences may be estimated with the Seidov criterion for the difference in energy densities. The radii and masses at the onset of deconfinement exhibit a linear relationship and thus define a critical compactness of the isentropic star configuration for which the transition occurs which for large enough $s / n_{B} ≳ 2$ is accompanied by an instability. The results of this study may be of relevance for uncovering the conditions for the supernova explodability of massive blue supergiant stars by the quark deconfinement mechanism. The accretion-induced deconfinement transition with thermal twin formation may contribute to explaining the origin of eccentric orbits in some binary systems and the origin of isolated millisecond pulsars.
Comments:
15 pages, 16 Figures, 1 table
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2406.17193 [pdf]
Universe(2024)·11 citations
02
[Submitted on 25 Jun 2024]
Moments of the charge distribution observed through electron scattering in H3 and He3
Emiko Hiyama · Toshio Suzuki
The moments of the charge distributions obtained by the analysis of electron-scattering data are examined in $^{3}$ H and $^{3}$ He. It is shown that the experimental form-factors are well explained, but the values of the moments of the charge distributions are not determined uniquly by the present analyses.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2406.17394 [pdf]
PTEP(2024)·6 citations
03
[Submitted on 25 Jun 2024]
Transient spin modes from relaxational axial kinetic theory
Shu Lin🇨🇳 · Haiqin Tang🇨🇳
We study the dynamics of spin mode by solving the axial kinetic equations under the relaxation time approximation in the presence of dissipative sources. We find transient spin modes in response to electric field with spacetime inhomogeneity, fluid acceleration and shear. To the lowest order in spatial momentum $k$ , we find the responses to electric field and acceleration can be interpreted as retarded response to temporal variations of magnetic field and vorticity respectively. The response to shear occurs at $O (k^{2})$ and can be reduced to retarded response to spatial variation of vorticity. Beyond lowest order, the responses to all three sources are non-local with branch cut in the dispersions. We argue that the non-locality is a consequence of the quasi-particle picture underlying the kinetic description. We also analyze spin transport equation taking into account spin response to temporal and spatial variations of vorticity. We find the corrections turn the original first order spin transport equation into a third order one (or a second order one in the homogeneous limit). The change in order of transport equation is a consequence of non-local nature of the responses, suggesting possible breakdown of gradient expansion in spin hydrodynamics for microscopic theories with quasi-particles.
Comments:
20 pages, 1 figure, published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2406.17632 [pdf]
PRD(2024)·7 citations
04
[Submitted on 25 Jun 2024]
Towards Hypernuclei from Nuclear Lattice Effective Field Theory
Fabian Hildenbrand🇩🇪 · Serdar Elhatisari🇹🇷 · Zhengxue Ren🇩🇪 · Ulf-G. Meißner🇩🇪
Understanding the strong interactions within baryonic systems beyond the up and down quark sector is pivotal for a comprehensive description of nuclear forces. This study explores the interactions involving hyperons, particularly the $Λ$ particle, within the framework of nuclear lattice effective field theory (NLEFT). By incorporating $Λ$ hyperons into the NLEFT framework, we extend our investigation into the $S = - 1$ sector, allowing us to probe the third dimension of the nuclear chart. We calculate the $Λ$ separation energies ( $B_{Λ}$ ) of hypernuclei up to the medium-mass region, providing valuable insights into hyperon-nucleon ( $Y N$ ) and hyperon-nucleon-nucleon ( $Y N N$ ) interactions. Our calculations employ high-fidelity chiral interactions at N $^{3}$ LO for nucleons and extend it to $Λ$ hyperons with leading-order S-wave $Y N$ interactions as well as $Y N N$ forces constrained only by the $A = 4, 5$ systems. Our results contribute to a deeper understanding of the SU(3) symmetry breaking and establish a foundation for future improvements in hypernuclear calculations.
Comments:
15 pages, 6 figures, 9 tables, typos corrected, extended discussion, final version accepted for publication
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Computational Physics (physics.comp-ph)
arXiv:
2406.17638 [pdf]
EPJA(2024)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE

Hybrid isentropic twin stars

Moments of the charge distribution observed through electron scattering in H3 and He3

Transient spin modes from relaxational axial kinetic theory

Towards Hypernuclei from Nuclear Lattice Effective Field Theory

Affiliations