Nuclear Theory·nucl-th

Thursday·May 29, 2025

8 papers—4 primary·4 cross-listed

05
Prospect of Constraining the EoS of Neutron Stars Using Post-Merger Signals
Soham Mitra🇮🇳 · Praveer Tiwari🇮🇳 · Archana Pai🇮🇳
Post-merger gravitational-wave emission from a binary neutron star merger carries crucial information about the equation of state (EoS) of matter at high temperatures. Current gravitational wave detectors have limited sensitivities at post-merger frequencies in the range [1.5, 4] kHz. Therefore, valuable inferences can only be made after combining information from multiple (BNS) events. Criswell et al. [Phys. Rev. D 107, 043021 (2023)] carries out an injection study to infer the radius posterior for a $1.6 M_{⊙}$ NS by combining the information from injected BNS events via the hierarchical Bayesian inference (HBI) formulation. This formulation utilizes empirical relations that connect the peak frequency of the post-merger remnant with the chirp mass of the system, and the EoS proxy parameter $R_{1.6}$ . In this work, we extend the HBI formulation to other EoS proxy parameters (i.e., the radius of (NS), $R_{1. X}$ , with masses 1.2, 1.4, and 1.8 $M_{⊙}$ ) and combine the four $R_{1. X}$ posteriors through the piecewise polytropic EoS model to obtain measurable constraints on the EoS of the NS. We show that the NS radii can be constrained to within $\sim$ 1 km ( $\sim$ 0.55 km) assuming uniform (astrophysical) prior on $R_{1. X}$ for injections in the A+ noise. We also study systematic biases in the analysis coming from the limitations of empirical relations.
↳ astro-ph.HEgr-qchep-phnucl-th+1J.Subatomic Part.Cosmol.(2026)·4 citations
06
Spin polarization of holographic baryon in strongly coupled fluid
Si-wen Li🇨🇳 · Shu Lin🇨🇳
The spin polarization for baryon in a hydrodynamic medium has been extensively studied in the weakly coupled regime using quantum kinetic theory. As a first study of this problem in the strongly coupled regime, we investigate holographically the spectral function of a probe baryon in the fluid-gravity background. This is done by carefully performing gradient expansion of the Dirac equation in the fluid-gravity background. Different contributions in the expansion are understood in terms of density matrices of the probe baryon and the medium. The resulting spectral functions indicate that the holographic baryonic is polarized as responses to fluid acceleration, shear stress and vorticity. The structures of the responses are similar to those found in weakly coupled studies.
↳ hep-thhep-phnucl-thPRD(2025)·4 citations
07
Probing the sensitivity of anisotropic flow coefficients to the initial nuclear structure in pO and OO collisions at the LHC
Aswathy Menon Kavumpadikkal Radhakrishnan🇮🇳 · Suraj Prasad🇮🇳 · Neelkamal Mallick🇫🇮 · Raghunath Sahoo🇮🇳 · Gergely Gábor Barnaföldi🇭🇺
RHIC and LHC have injected $^{16} O$ nuclei in their accelerator complexes with a focus on investigating collectivity and the origin of quark-gluon plasma signatures in small collision systems. The $^{16} O$ nuclei are known to possess clusters of $α$ -particles ( $^{4} He$ ) inside the nucleus. This paper attempts to study the clustered-nuclear-geometry dependence of anisotropic flow coefficients such as elliptic flow ( $v_{2}$ ) and triangular flow ( $v_{3}$ ), which are sensitive to the nuclear geometry of colliding nuclei. The study is performed in pO and OO collisions at $s_{NN} = 9.61$ ~TeV and 7~TeV respectively, employing a hybrid model encompassing IP-Glasma + MUSIC + iSS + UrQMD. The results of the clustered nuclear geometry are compared with those of the Woods\,--\,Saxon nuclear profile. Both initial and final state anisotropies are estimated. This study is thus one of its first kind, where the study of anisotropic flow coefficients for pO and OO collisions is presented using a hybrid hydrodynamics model. While the effect of $α$ -clustering in pO is found to be small, it is significant for each observable studied in OO collisions. It is also observed that the magnitude of this effect has a noteworthy dependence on the size of the \textsuperscript{4}He.
↳ hep-phhep-exhep-thnucl-ex+1PLB(2025)·7 citations
08
Renormalizing the Quark-Meson-Diquark Model
Hosein Gholami🇩🇪 · Lennart Kurth🇩🇪 · Ugo Mire🇩🇪 · Michael Buballa🇩🇪 · Bernd-Jochen Schaefer🇩🇪
We present a comprehensive study of the two-flavor Quark--Meson--Diquark (QMD) model by comparing a renormalization approach with a renormalization-group (RG) consistent mean-field formulation based on the functional renormalization group (FRG). The renormalized QMD model allows analytical investigations of key quantities such as the zero-temperature diquark gap and the critical temperature for color superconductivity, ultimately reproducing the exact BCS relation in the high-density limit. We carry out the same analysis for different schemes of RG-consistent QMD models. We show that the RG-consistent approach yields a phase diagram and thermodynamic properties qualitatively similar to those of the renormalized model, provided both are embedded within a unified scheme that ensures consistent vacuum properties. In particular, both treatments recover the Stefan--Boltzmann limit at high densities. On the other hand, whether the BCS relation for the critical temperature is satisfied depends on the details of the RG-consistent setup. Our results highlight the relevance of renormalization and RG-consistent methods for accurately capturing the thermodynamics of QMD and related effective models with diquark degrees of freedom.
↳ hep-phhep-thnucl-thPRD(2026)·22 citations

Affiliations

first authorsco-authorsvia INSPIRE

Prospect of Constraining the EoS of Neutron Stars Using Post-Merger Signals

Spin polarization of holographic baryon in strongly coupled fluid

Probing the sensitivity of anisotropic flow coefficients to the initial nuclear structure in pO and OO collisions at the LHC

Renormalizing the Quark-Meson-Diquark Model

Affiliations