Nuclear Theory·nucl-th

Friday·October 28, 2022

11 papers—6 primary·5 cross-listed

07
[Submitted on 26 Oct 2022] (cross-list from hep-ph)
$C P$ violation in $η^{(')} \to π^{+} π^{-} μ^{+} μ^{-}$ decays
Maximilian Zillinger🇩🇪 · Bastian Kubis🇩🇪 · Pablo Sánchez-Puertas🇪🇸
It has been pointed out recently that a certain set of dimension-6 scalar $P$ - and $C P$ -violating light-quark-muon operators may be tested in $η$ and $η^{'}$ decays to various final states involving $μ^{+} μ^{-}$ pairs, at a level not yet excluded by constraints from electric dipole moments. We here work out the hadronic matrix elements required for the predictions for the decays $η, η^{'} \to π^{+} π^{-} μ^{+} μ^{-}$ . We relate a new asymmetry in the angular distribution between the dipion and dimuon decay planes to the corresponding Wilson coefficients. Despite the advantage of not requiring the measurement of muon polarization, the projected sensitivities are shown to be moderate due to a combination of small phase space and chiral suppression. Such sensitivity studies are most timely in view of upcoming or planned high-statistics $η^{(')}$ experiments such as the JLab eta factory or REDTOP.
Comments:
23 pages, 1 figure, 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2210.14925 [pdf]
JHEP(2022)·13 citations
08
[Submitted on 27 Oct 2022] (cross-list from hep-ph)
Flow of charge and heat in thermal QCD within the weak magnetic field limit: A BGK model approach
Anowar Shaikh🇮🇳 · Shubhalaxmi Rath🇮🇳 · Sadhana Dash🇮🇳 · Binata Panda🇮🇳
We have computed the charge and heat transport coefficients of hot QCD matter by solving the relativistic Boltzmann transport equation using the BGK model approximation with a modified collision integral in the weak magnetic field regime. This modified collision integral enhances both charge and heat transport phenomena which can be understood by the large values of the above-mentioned coefficients in comparison to the relaxation collision integral. We have also presented a comparative study of coefficients like the electrical conductivity ( $σ_{e l}$ ), Hall conductivity ( $σ_{H}$ ), thermal conductivity ( $κ$ ) and Hall-type thermal conductivity( $κ_{H}$ ) in weak and strong magnetic fields in the BGK model approximation. The effects of weak magnetic field and finite chemical potential on the transport coefficients have been explored using a quasiparticle model. Moreover, we have also studied the effects of weak magnetic field and finite chemical potential on Lorenz number, Knudsen number, specific heat, elliptic flow and Wiedemann-Franz law.
Comments:
41 pages, 26 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2210.15388 [pdf]
PRD(2023)·11 citations
09
[Submitted on 27 Oct 2022] (cross-list from hep-ph)
Cumulants from short-range correlations and baryon number conservation - next-to-leading order
Michał Barej🇵🇱 · Adam Bzdak🇵🇱
We calculate the baryon number cumulants within acceptance with short-range correlations and global baryon number conservation in terms of cumulants in the whole system without baryon conservation. We extract leading and next-to-leading order terms of the large baryon number limit approximation. Our results extend the findings of Refs. [1,2]. These approximations are checked to be very close to the exact results.
Comments:
17 pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2210.15394 [pdf]
PRC(2023)·5 citations
10
[Submitted on 27 Oct 2022] (cross-list from hep-ph)
Thermodynamic properties of non-Hermitian Nambu--Jona-Lasinio models
Alexander Felski🇩🇪 · Alireza Beygi🇩🇪 · S. P. Klevansky🇩🇪
We investigate the impact of non-Hermiticity on the thermodynamic properties of interacting fermions by examining bilinear extensions to the $3 + 1$ dimensional $S U (2)$ -symmetric Nambu--Jona-Lasinio (NJL) model of quantum chromodynamics at finite temperature and chemical potential. The system is modified through the anti- $P T$ -symmetric pseudoscalar bilinear $ψ ˉ γ_{5} ψ$ and the $P T$ -symmetric pseudovector bilinear $i B_{ν} ψ ˉ γ_{5} γ^{ν} ψ$ , introduced with a coupling $g$ . Beyond the possibility of dynamical fermion mass generation at finite temperature and chemical potential, our findings establish model-dependent changes in the position of the chiral phase transition and the critical end-point. These are tunable with respect to $g$ in the former case, and both $g$ and $∣ B ∣/ B_{0}$ in the latter case, for both lightlike and spacelike fields. Moreover, the behavior of the quark number, entropy, pressure, and energy densities signal a potential fermion or antifermion excess compared to the standard NJL model, due to the pseudoscalar and pseudovector extension respectively. In both cases regions with negative interaction measure $I = ϵ - 3 p$ are found. Future indications of such behaviors in strongly interacting fermion systems, for example in the context of neutron star physics, may point toward the presence of non-Hermitian contributions. These trends provide a first indication of curious potential mechanisms for producing non-Hermitian baryon asymmetry. In addition, the formalism described in this study is expected to apply more generally to other Hamiltonians with four-fermion interactions and thus the effects of the non-Hermitian bilinears are likely to be generic.
Comments:
25 pages, 15 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2210.15503 [pdf]
PRD(2023)·4 citations
11
[Submitted on 27 Oct 2022] (cross-list from astro-ph.HE)
Twin stars as probes of the nuclear equation of state: effects of rotation through the PSR J0952-0607 pulsar and constraints via the tidal deformability from the GW170817 event
Lazaros Tsaloukidis🇩🇪 · P.S. Koliogiannis🇬🇷 · A. Kanakis-Pegios🇬🇷 · Ch.C. Moustakidis🇬🇷
In agreement with the constantly increasing gravitational wave events, new aspects of the internal structure of compact stars can be considered. A scenario in which a first order transition takes place inside these stars is of particular interest as it can lead, under conditions, to a third gravitationally stable branch (besides white dwarfs and neutron stars), the twin stars. The new branch yields stars with the same mass as normal compact stars but quite different radii. In the present work, we focus on hybrid stars undergone a hadron to quark phase transition near their core and how this new stable configuration arises. Emphasis is to be given on the aspects of the phase transition and its parametrization in two different ways, namely with Maxwell and Gibbs construction. We systematically study the gravitational mass, the radius, and the tidal deformability, and we compare them with the predictions of the recent observation by LIGO/VIRGO collaboration, the GW170817 event, along with the mass and radius limits, suggesting possible robust constraints. Moreover, we extent the study in order to include rotation effects on the twin stars configurations. The recent discovery of the fast rotating supermassive pulsar PSR J0952-0607 triggered the effort to constrain the equation of state and moreover to examine possible predictions related to the phase transition in dense nuclear matter. We pay special attention to relate the PSR J0952-0607 pulsar properties with the twin stars predictions and mainly to explore the possibility that the existence of such a massive object would rule out the existence of twin stars. Finally, we discuss the constraints on the radius and mass of the recently observed compact object within the supernova remnant HESS J1731-347. The estimations implies that this object is either the lightest neutron star known, or a star with a more exotic equation of state.
Comments:
v1: 16 pages, 17 figures; v2 : 17 pages, 17 figures, updated references; accepted for publication in Physical Review D
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2210.15644 [pdf]
PRD(2023)·48 citations

Affiliations

first authorsco-authorsvia INSPIRE

CP violation in η(′)→π+π−μ+μ− decays

Flow of charge and heat in thermal QCD within the weak magnetic field limit: A BGK model approach

Cumulants from short-range correlations and baryon number conservation - next-to-leading order

Thermodynamic properties of non-Hermitian Nambu--Jona-Lasinio models

Twin stars as probes of the nuclear equation of state: effects of rotation through the PSR J0952-0607 pulsar and constraints via the tidal deformability from the GW170817 event

Affiliations

$C P$ violation in $η^{(')} \to π^{+} π^{-} μ^{+} μ^{-}$ decays