Nuclear Theory·nucl-th

Tuesday·May 27, 2025

15 papers—7 primary·8 cross-listed

08
[Submitted on 23 May 2025] (cross-list from astro-ph.HE)
Astrophysics with Compact Objects: An Indian Perspective, Present Status and Future Vision
Manjari Bagchi · Prasanta Bera · Aru Beri · Dipankar Bhattacharya · Bhaswati Bhattacharyya · Sudip Bhattacharyya · Manoneeta Chakraborty · Debarati Chatterjee · Sourav Chatterjee · Indranil Chattopadhyay · Santabrata Das · Sushan Konar and 9 other authors
Astrophysical compact objects, viz., white dwarfs, neutron stars, and black holes, are the remnants of stellar deaths at the end of their life cycles. They are ideal testbeds for various fundamental physical processes under extreme conditions that are unique in nature. Observational radio astronomy with uGMRT and OORT facilities has led to several important breakthroughs in studies of different kinds of pulsars and their emission mechanisms. On the other hand, accretion processes around compact objects are at the core of Indian astronomy research. In this context, AstroSat mission revolutionized spectro-temporal observations and measurements of accretion phenomena, quasi-periodic oscillations, and jet behaviour in binary systems hosting compact objects. Moreover, recently launched XPoSat mission is set to provide an impetus to these high-energy phenomena around compact objects by enabling us to conduct polarization measurements in the X-ray band. Further, during the past decade, numerous gravitational wave signals have been observed from coalescing black holes and neutron stars in binary systems. Recent simultaneous observation of the GW170817 event in both gravitational waves and electromagnetic channels has ushered in the era of multi-messenger astronomy. In the future, synergistic efforts among several world-class observational facilities, e.g., LIGO-India, SKA, TMT, etc., within the Indian astrophysics community will provide a significant boost to achieve several key science goals that have been delineated here. In general, this article plans to highlight scientific projects being pursued across Indian institutions in this field, the scientific challenges that this community would be focusing on, and the opportunities in the coming decade. Finally, we have also mentioned the required resources, both in the form of infrastructural and human resources.
Comments:
21 pages, no figure, accepted in Journal of Astrophysics and Astronomy
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2505.18238 [pdf]
J.Astrophys.Astron.(2025)·1 citation
09
[Submitted on 23 May 2025] (cross-list from astro-ph.HE)
Filling fractions for the formation of nuclear pasta in neutron stars: semiclassical vs liquid-drop predictions
Nikolai N. Shchechilin🇧🇪 · Nicolas Chamel🇧🇪 · Andrey I. Chugunov🇷🇺
Historically, a sequence of nuclear pasta shapes was predicted to appear in the deepest region of the inner crust of a neutron star within the compressible liquid-drop picture, when the filling fraction $u$ exceeds some threshold values. However, later calculations showed that these values depend on the details of the liquid-drop model. Here we investigate the existence of pasta in neutron stars within the semiclassical extended Thomas-Fermi approach using various generalized Skyrme functionals. The filling fractions for the different transitions are found to be quasi-universal, unlike the pasta density ranges governed by the symmetry energy at relevant densities. In particular, pasta emerge at $u_{sp} \approx 0.13 - 0.15$ . By applying a simplified stability criterion within the liquid-drop framework, we show that these values of $u_{sp}$ can be explained by the nuclear curvature correction. In this way, the abundance of pasta can be easily estimated. This criterion can also be used to optimize the search of pasta within the more realistic extended Thomas-Fermi approach.
Comments:
17 pages, 6 figures, 1 table; accepted to EPJA
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2505.18309 [pdf]
EPJA(2025)·3 citations
10
[Submitted on 23 May 2025] (cross-list from nucl-ex)
High-precision Penning trap mass measurements of neutron-rich chlorine isotopes at the N=28 shell closure
H. Erington · G. Bollen · G. Dykstra · A. Hamaker · C. M. Ireland · C. R. Nicoloff · D. Puentes · R. Ringle · S. Schwarz · C. S. Sumithrarachchi · A. A. Valverde · I. T. Yandow
Although it is known that the $N = 28$ spherical shell closure erodes, the strength of the closure with decreasing proton number $Z < 20$ is an open question in nuclear structure. In this region of interest, direct high-precision mass measurements of neutron-rich $^{43 - 45}$ Cl isotopes were performed at the Low Energy Beam and Ion Trap (LEBIT) when coupled to the National Superconducting Cyclotron Lab. The resulting mass excesses (MEs) are ME( $^{43}$ Cl) = -24114.4(1.7) keV, ME( $^{44}$ Cl) = -20450.8(10.6) keV, and ME( $^{45}$ Cl) = -18240.1(3.7) keV, and improve the uncertainty of these masses by up to a factor of ~40 compared to the previous values reported in the 2020 Atomic Mass Evaluation. Comparison to $ab initio$ calculations using the Valence-Space In-Medium Similarity Renormalization Group (VS-IMSRG) shows good agreement up to and including the closure.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2505.18354 [pdf]
PRC(2025)·0 citations
11
[Submitted on 23 May 2025] (cross-list from hep-lat)
Lattice QCD Benchmark of Proton Helicity and Flavor-Dependent Unpolarized Transverse Momentum-Dependent Parton Distribution Functions at Physical Quark Masses
Dennis Bollweg🇺🇸 · Xiang Gao🇺🇸 · Swagato Mukherjee🇺🇸 · Yong Zhao🇺🇸
We present the first lattice QCD calculations of the isovector helicity transverse momentum-dependent parton distribution function (TMDPDF) and the flavor-dependent unpolarized TMDPDFs for up and down quarks in the proton. Our computations utilize domain-wall fermion discretization with physical quark masses. Employing Coulomb-gauge-fixed quark correlation functions within the large-momentum effective theory framework, we access nonperturbative transverse quark separations $b_{T}$ up to approximately 1 fm, corresponding to transverse momenta as low as 200 MeV. Based on the quasi-TMD factorization theorem, we construct renormalization-group-invariant ratios that are equal to the corresponding light-cone TMDPDF ratios. At moderate $x$ , our results reveal that the isovector helicity and unpolarized TMDPDFs exhibit nearly identical transverse structure up to a normalization factor, and the unpolarized distributions display only mild flavor dependence. These findings not only support key trends observed in recent global analyses but also provide robust, nonperturbative constraints that can distinguish between different parameterizations. This work establishes a first-principles benchmark for TMDPDFs, offering valuable input for ongoing and future experimental efforts to map the proton's three-dimensional structure.
Comments:
5 pages, 4 figures, 2 ancillary files. Corrected typos to match the publication version
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2505.18430 [pdf]
PRL(2025)·10 citations
12
[Submitted on 24 May 2025] (cross-list from gr-qc)
Noncovariant parabolic theories of relativistic diffusion
Lorenzo Gavassino🇺🇸
A new first-order theory of relativistic dissipation has been recently proposed, where viscous effects are incorporated using the traditional Navier-Stokes framework. Its main novelty is the avoidance of dynamical instabilities by allowing different observers to use equations that are not related by exact Lorentz transformations. In this work, we explore the implications of this non-covariance in depth. In particular, we discuss how predictions differ between observers moving at nearly luminal speeds relative to each other. We find that all disagreements stem from the relativity of simultaneity, which introduces frame-dependent anisotropic delays in the diffusive process. These anisotropies significantly limit the applicability of the equation used by observers who move very fast relative to the medium. However, the magnitude of the related error remains finite at infinite Lorentz factors, meaning that it is possible to find a regime where all observers agree on the outcome of experiments.
Comments:
14 pages, 5 captioned figures, published on PRD (see https://journals.aps.org/prd/abstract/10.1103/ppy5-654c)
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2505.18815 [pdf]
PRD(2025)·6 citations
13
[Submitted on 25 May 2025] (cross-list from nucl-ex)
Electric dipole polarizability constraints on neutron skin and symmetry energy
P. von Neumann-Cosel (1,2)🇩🇪 · A. Tamii (3) ((1) Institut für Kernphysik, Technische Universität Darmstadt, Germany, (2) Norwegian Nuclear Research Center and Department of Physics, University of Oslo, Norway, (3) Research Center for Nuclear Physics, University of Osaka, Japan)🇯🇵
We review the experimental knowledge on the dipole polarizability (DP) of nuclei and its relation to the neutron skin thickness and properties of the neutron-rich matter equation of state (EOS). The discussion focuses on recent experiments using relativistic Coulomb excitation in inelastic proton scattering at extreme forward angles covering a mass range from $^{40}$ Ca to $^{208}$ Pb. Constraints on the neutron skins and the density dependence of the symmetry energy are derived from systematic comparison to calculations based on density functional theory (DFT) and ab initio methods utilizing interactions derived from chiral effective field theory ( $χ$ EFT). The results consistently favor a soft EOS around or slightly below the saturation point. An outlook is given on possible improvements of the precision achievable in stable nuclei and studies of exotic neutron-rich unstable nuclei with upcoming experimental facilities.
Comments:
30 pages, 13 figures, accepted for publication in Frontiers in Physics
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2505.19229 [pdf]
Front.in Phys.(2025)·7 citations
14
[Submitted on 25 May 2025] (cross-list from hep-th)
The Gauge Theory Bootstrap: Predicting pion dynamics from QCD
Yifei He🇫🇷 · Martin Kruczenski🇺🇸
The Gauge Theory Bootstrap [arXiv:2309.12402, arXiv:2403.10772] computes the strongly coupled pion dynamics by considering the most general scattering matrix, form factors and spectral densities and matching them with perturbative QCD at high energy and with weakly coupled pions at low energy. In this work, we show that further constraints on the spectral densities significantly reduce the possible solutions to a small set of qualitatively similar ones. Quantitatively, the precise solution is controlled by the asymptotic value of the form factors and SVZ sum rules. We also introduce an iterative procedure that, starting from a generic feasible point, converges to a unique solution parameterized by the UV input. For the converged solution we compute masses and widths of resonances that appear, scattering lengths and effective ranges of partial waves, low energy coefficients in the effective action. Additionally, we use these results to discuss the thermodynamics of a pion gas including pair correlations of pions with same and opposite charge.
Comments:
v3: 27 pages + appendices, 15 figures, sections 2.2 and 6.1 extended, section 2.4 added, typos corrected, numerical program available at https://github.com/hyfysics/gauge-theory-bootstrap/tree/main
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2505.19332 [pdf]
PTEP(2026)·16 citations
15
[Submitted on 26 May 2025] (cross-list from nucl-ex)
Study of $p_{T}$ -differential radial flow in blast-wave model
Swati Saha🇮🇳 · Ranbir Singh🇮🇳 · Bedangadas Mohanty🇮🇳
The transverse momentum-differential radial flow observable $v_{0} (p_{T})$ , recently proposed and measured by the ATLAS and ALICE collaborations, provides a novel tool to probe radial expansion dynamics in high-energy heavy-ion collisions. In this work, we conduct a detailed study of $v_{0} (p_{T})$ using a blast-wave model that incorporates hydrodynamic-like expansion and thermal emission. We introduce event-by-event fluctuations in the transverse expansion velocity and kinetic freeze-out temperature using Gaussian probability distributions. Our results show that increasing the mean expansion velocity leads to a clear mass ordering in $v_{0} (p_{T})$ , while fluctuations in both expansion velocity and freeze-out temperature significantly enhance the magnitude of $v_{0} (p_{T})$ , particularly at higher $p_{T}$ . We fit blast-wave model calculations for identified hadrons ( $π$ , K, and p) to recent ALICE data from Pb--Pb collisions at $s_{NN}$ = 5.02 TeV using a Bayesian parameter estimation framework. The extracted mean transverse expansion velocity decreases, while the kinetic freeze-out temperature increases, from central to peripheral collisions. Additionally, the freeze-out temperatures inferred from $v_{0} (p_{T})$ are systematically higher than those obtained from conventional $p_{T}$ -spectra fits, likely due to the reduced sensitivity of $v_{0} (p_{T})$ to resonance decay contributions.
Comments:
10 pages and 8 figures
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2505.19697 [pdf]
PRC(2025)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE