Nuclear Theory·nucl-th

Tuesday·October 29, 2024

14 papers—7 primary·7 cross-listed

08
A Universal Bound on QCD Axions from Supernovae
Konstantin Springmann🇩🇪 · Michael Stadlbauer🇩🇪 · Stefan Stelzl🇨🇭 · Andreas Weiler🇩🇪
We identify a new production channel for QCD axions in supernova environments that contributes to axion emissivity for all models solving the strong CP problem. This channel arises at tree-level from a shift-symmetry-breaking operator constructed at next-to-leading order in Chiral Perturbation Theory. In scenarios where model-dependent derivative couplings to nucleons are absent, this sets the strongest model-independent constraint on the axion mass, improving on existing bounds by two orders of magnitude.
↳ hep-phastro-ph.HEnucl-thPRD(2025)·42 citations
09
Resonant shattering flares as asteroseismic tests of chiral effective field theory
Duncan Neill🇬🇧 · David Tsang🇬🇧 · Christian Drischler🇺🇸 · Jeremy W. Holt🇺🇸 · William G. Newton🇺🇸
Chiral effective field theory ( $χ$ EFT) has proved to be a powerful microscopic framework for predicting the properties of neutron-rich nuclear matter with quantified theoretical uncertainties up to about twice the nuclear saturation density. Tests of $χ$ EFT predictions are typically performed at low densities using nuclear experiments, with neutron star (NS) constraints only being considered at high densities. In this work, we discuss how asteroseismic quasi-normal modes within NSs could be used to constrain specific matter properties at particular densities, not just the integrated quantities to which bulk NS observables are sensitive. We focus on the crust-core interface mode, showing that measuring this mode's frequency would provide a meaningful test of $χ$ EFT at densities around half the saturation density. Conversely, we use nuclear matter properties predicted by $χ$ EFT to estimate that this mode's frequency is around 185 $\pm$ 50 Hz. Asteroseismic observables such as resonant phase shifts in gravitational-wave signals and multimessenger resonant shattering flare timings, therefore, have the potential to provide useful tests of $χ$ EFT.
↳ astro-ph.HEnucl-thPRC(2025)·2 citations
10
Re analysis of Temperature Dependent Neutron Capture Rates and Stellar \b{eta} decay Rates of 95 98Mo
Abdul Kabir · Jameel-Un Nabi · Muhammad Tahir · Abdul Muneem · Zain Ul Abideen
The neutron capture rates and temperature dependent stellar beta decay rates of Mo isotopes are investigated within the framework of the statistical code (Talys v1.96) and proton neutron quasi particle random phase approximation (pnQRPA) models. The Maxwellian average cross section (MACS) and neutron capture rates for 95 98Mo(n,{\gamma}) 96 99Mo radiative capture processes are analyzed within the framework of statistical code Talys v1.96 based on the phenomenological nuclear level density (NLD) parameters and gamma strength functions (GSFs). The current model based computed data for MACS provide a good comparison with the existing measured data. The temperature dependent stellar \b{eta} decay rates of 95 98Mo are investigated at different densities within the framework of the pn-QRPA model. For the considered temperature range, the neutron capture rates were found to be higher, by orders of magnitude, than the stellar \b{eta} rates.
↳ astro-ph.SRnucl-thCPC(2024)·1 citation
11
Revisiting $K N$ elastic and charge exchange reactions in search of the pentaquark $Θ^{+}$ baryon
Byung-Geel Yu🇰🇷 · Kook-Jin Kong🇰🇷 · Tae Keun Choi🇨🇦
In the search for the pentaquark $Θ^{+}$ baryon, the world data on $K^{+} n \to K^{+} n$ and $K^{+} n \to K^{0} p$ reactions on the deuteron target and $K^{0} p \to K^{+} n$ and $K_{L}^{0} p \to K_{S}^{0} p$ reactions on the hydrogen target are revisited to study the isoscalar component of the scattering amplitudes. The determination of the $s$ - and $p$ -wave phase shifts for the two former channels on the deuteron target is presented in the low momentum region with the uncertainty due to the deuteron form factors at forward angles discussed. For the reactions on hydrogen targets, a similarity expected from time reversal between the charge exchange processes $K^{+} n \to K^{0} p$ and $K^{0} p \to K^{+} n$ is exploited, while we present the analysis of the $K_{L}^{0} p \to K_{S}^{0} p$ scattering based on the $s$ -wave phase shift for low momenta combined with the $t$ -channel $ρ^{0} (775) + ω (782) + ϕ (1020)$ vector meson exchange at high momenta. With the mass 1535 MeV and decay width 5 MeV the possibility of the $Θ^{+}$ in the Breit-Wigner (BW) form is tested in the differential cross section measured by C. J. S. Damerell {\it et\ al.} at $P_{Lab} = 434$ MeV/ $c$ and polarization. Our analysis suggests measuring the polarization observable rather than the differential cross section, which has sufficient sensitivity to distinguish the $Θ^{+}$ baryon among all spin and parity states $J^{P} = 1/ 2^{\pm}$ and $3/ 2^{\pm}$ .
↳ hep-phnucl-thActa Phys.Polon.B(2025)·0 citations
12
Fluctuations and correlations of quark spin in hot and dense QCD matter
Hao-Lei Chen🇨🇳 · Wei-jie Fu🇨🇳 · Xu-Guang Huang🇨🇳 · Guo-Liang Ma🇨🇳
In this work, we examine the impact of QCD phase transitions on the quark spin fluctuations and correlations. We propose the quark-antiquark correlation, which relates to the vector meson spin alignment and the $Λ - Λ ˉ$ correlation, can be used as a novel probe of the critical end point (CEP) in the QCD phase diagram. Using the Nambu-Jona-Lanisio model, we qualitatively study the properties of quark-antiquark spin correlations. Our findings reveal a peak structure near the CEP of the chiral phase transition, which may serve as an experimental signature of the CEP and account for the non-monotonic behavior of $ϕ$ meson alignment at low collision energies observed recently in experiments.
↳ hep-phnucl-exnucl-thPRL(2025)·22 citations
13
Effects of dark boson mediated feeble interaction between dark matter (DM) and quark matter on $f$ -mode oscillation of DM admixed quark stars
O. P. Jyothilakshmi🇮🇳 · Lakshmi J. Naik🇮🇳 · Debashree Sen🇰🇷 · Atanu Guha🇰🇷 · V. Sreekanth🇮🇳
We investigate the behavior of the prominent non-radial fundamental $f$ -mode oscillations of dark matter (DM) admixed strange quark stars (DMSQSs), by adopting an equation of state (EoS) developed in Ref.~\cite{Sen:2022pfr}, which considers the possible presence of feebly interacting DM in strange quark stars (SQSs) for the first time. Within the model, feeble interaction between fermionic DM $χ$ and strange quark matter (SQM) is invoked via a vector new physics mediator $ξ$ with coupling strength $y_{ξ}$ . The pure SQM is described by the vector MIT Bag model. By varying different EoS parameters, the structural properties viz. the mass, radius and tidal deformability ( $Λ$ ) of the DMSQSs are studied with respect to various astrophysical constraints. We study in detail the $f$ -mode spectra within the Cowling approximation by obtaining the frequencies as a function of mass, compactness and $Λ$ of the star. To the best of our knowledge, this study represents the first analysis of non-radial $f$ -mode oscillations of DMSQSs. Our investigation indicates that the presence of DM and its interaction with SQM has great impact on the $f$ -modes. We show that the $f$ -mode frequencies are larger for DMSQSs, which are largely populated with massive DM fermions, compared to the SQSs. Further, we obtain a linear empirical relation between the $f$ -modes and the average density of the star. We also find that the mass-scaled angular frequency varies universally with compactness and $ln Λ$ for DMSQSs. Further, our studies indicate that the inclusion of DM in compact stars reduces the deviation of $f$ -mode frequency from general relativistic to Cowling approximation.
↳ hep-phastro-ph.HEgr-qcnucl-thEPJC(2025)·11 citations
14
Elastic Dijet Production in Electron Scattering on a Longitudinally Polarized Proton at Small $x$ : A Portal to Orbital Angular Momentum Distributions
Yuri V. Kovchegov🇺🇸 · Brandon Manley🇺🇸
We calculate the elastic production of dijets from electron collisions with a longitudinally polarized proton target at small values of the Bjorken $x$ variable. Building on the pioneering proposals of \cite{Hatta:2016aoc,Bhattacharya:2022vvo, Bhattacharya:2023hbq, Bhattacharya:2024sck} for measuring the quark and gluon orbital angular momentum (OAM) distributions, our focus is on both the longitudinal double spin asymmetry (DSA) and longitudinal single spin asymmetry (SSA). We compute the numerators of these asymmetries in the small- $x$ formalism of the light-cone operator treatment. Utilizing the small- $x$ expressions for the OAM distributions derived in our earlier paper, we demonstrate that the DSA provides a robust probe for both the quark and gluon OAM distributions within the proton. In contrast, we find that while the SSA is also sensitive to the OAM distributions, extraction of the latter from the SSA would require new developments in small- $x$ theory and phenomenology, and is probably not feasible at this point in time. These findings highlight the potential of DSA measurements in elastic dijet production at the future Electron-Ion Collider to provide the first-ever direct access to the quark and gluon OAM distributions at small $x$ , paving the way for new insights into the proton spin puzzle.
↳ hep-phhep-exnucl-exnucl-thPRD(2025)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE

A Universal Bound on QCD Axions from Supernovae

Resonant shattering flares as asteroseismic tests of chiral effective field theory

Re analysis of Temperature Dependent Neutron Capture Rates and Stellar \b{eta} decay Rates of 95 98Mo

Revisiting KN elastic and charge exchange reactions in search of the pentaquark Θ+ baryon

Fluctuations and correlations of quark spin in hot and dense QCD matter

Effects of dark boson mediated feeble interaction between dark matter (DM) and quark matter on f-mode oscillation of DM admixed quark stars

Elastic Dijet Production in Electron Scattering on a Longitudinally Polarized Proton at Small x: A Portal to Orbital Angular Momentum Distributions

Affiliations

Revisiting $K N$ elastic and charge exchange reactions in search of the pentaquark $Θ^{+}$ baryon

Effects of dark boson mediated feeble interaction between dark matter (DM) and quark matter on $f$ -mode oscillation of DM admixed quark stars

Elastic Dijet Production in Electron Scattering on a Longitudinally Polarized Proton at Small $x$ : A Portal to Orbital Angular Momentum Distributions