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Nuclear Theory·nucl-th

Tuesday·June 3, 2025

16 papers—5 primary·11 cross-listed

All16Primary5Cross-lists11
  1. 01

    Role of thermal fluctuations in nucleation of three-flavor quark matter

    Mirco Guerrini🇮🇹 · Giuseppe Pagliara🇮🇹 · Andrea Lavagno🇮🇹 · Alessandro Drago🇮🇹

    We present a framework that aims to investigate the role of thermal fluctuations of the matter composition and color-superconductivity in the nucleation of three-flavor deconfined quark matter in the typical conditions of high-energy astrophysical systems related to compact stars. It is usually assumed that the flavor composition is locally fixed during the formation of the first seed of deconfined quark matter since weak interaction acts too slowly to re-equilibrate flavors. However, the matter composition fluctuates around its average equilibrium values at the typical temperatures of high-energy astrophysical processes. Here, we extend our previous two-flavor nucleation formalism to a three-flavor case. We develop a thermodynamic framework incorporating finite-size effects and thermal fluctuations of local composition to compute the nucleation probability as the product of droplet formation and composition fluctuation rates. Moreover, we discuss the role of color-superconductivity in nucleation, arguing that it can play a role only in systems larger than the typical coherence length of diquark pairs. We found that thermal fluctuations of the matter composition lead to lowering the potential barrier between the metastable hadronic phase and the stable quark phase. Moreover, the formation of diquark pairs reduces the critical radius and thus the potential barrier in the low baryon density and temperature regime.

    nucl-thastro-ph.HEUniverse(2025)·3 citations
  2. 02

    Learning about neutron star composition from the slope of the mass-radius diagram

    Márcio Ferreira🇵🇹 · Constança Providência🇵🇹

    The slope of the neutron star mass-radius curve, , is studied to understand the information it may carry about the composition of neutron stars, particularly with regard to the presence of non-nucleonic degrees of freedom. This study uses two large sets of relativistic mean-field equations of state with either nucleonic or nucleonic and hyperonic degrees of freedom, and imposes constraints obtained from GW170817 and the pulsars PSR J0030+0451 and PSR J0740+6620. It is shown that: i) some mass-radius curves are characterized by a negative slope from one solar mass up to the maximum mass; ii) other equations of state (EoS) have a positive slope for a given range of masses below the maximum star mass. Within the set of models considered, the first set includes only a very small number of hyperonic EoS: less than 0.5\% of the total number of hyperonic stars and approximately one third of the nucleonic EoS. We have also analyzed the sign of the slope for neutron star masses of 1.2, 1.4 and 1.8. Only approximately 1\% of hyperonic equations of state (EoS) predict a negative slope for 1.4 stars, whereas over 90\% of nucleonic stars have a negative slope at this mass. Finally, almost all stars have a negative slope at 1.8. A positive slope at 1.4 may indicate the presence of non-nucleonic degrees of freedom within neutron stars. The nuclear matter property that distinguishes the different scenarios most clearly is the curvature of the symmetry energy. Nucleonic EoSs with a positive slope predict the highest values, which can exceed 100 MeV.

    nucl-thastro-ph.HEhep-phPRD(2025)·12 citations
  3. 03

    Perspectives for hyperon and hypernuclei physics

    Jin-Hui Chen🇨🇳 · Li-Sheng Geng🇨🇳 · Emiko Hiyama🇯🇵 · Zhi-Wei Liu🇨🇳 · Josef Pochodzalla🇩🇪

    Hypernuclei, nuclei containing one or more hyperons, serve as unique laboratories for probing the non-perturbative quantum chromodynamics (QCD). Recent progress in hypernuclear physics, driven by advanced experimental techniques and theoretical innovations, is briefly reviewed with a focus on key findings and unresolved challenges, such as the precise determination of the hypertriton binding energy, investigations of charge symmetry breaking in mirror hypernuclei, and the search for exotic systems, including the neutral nn state. Experimental breakthroughs, including invariant-mass analyses and femtoscopy studies in heavy-ion collisions, as well as high-resolution -spectroscopy, have enabled precise studies of light hypernuclei and offered critical insights into the hyperon-nucleon interaction. Theoretical progress, including ab initio calculations based on chiral effective field theory and lattice QCD, has further enhanced our understanding of hyperon-nucleon and hyperon-hyperon interactions.

    nucl-thnucl-exChin.Phys.Lett.(2025)·18 citations
  4. 04

    Transport Theory and Correlation Measurements: Coming to Terms on Emission Sources

    Pierre Nzabahimana · Pawel Danielewicz · Giuseppe Verde

    Two-particle correlations play a pivotal role in understanding the space-time characteristics of particle emission in Heavy-ion collisions. These characteristics are typically represented by a relative emission source and can be obtained using transport model simulations such as the Boltzmann- Uehling-Uhlenbeck (BUU) transport model. In this paper, we utilize the BUU transport model to simulate the p-p source. Subsequently, we integrate this source and the p-p kernel within the KP formula to calculate the correlations. By comparing the correlations obtained from the BUU simulation with those obtained using imaging methods, such as the deblurring method, we aim to gain a deeper understanding of the impact of fast and slow emissions on the measured correlations. Specifically, this comparison is used as a tool to determine a function (tail) that represents the relative distribution of the particle pair from secondary decay emissions. Thus, we correct the BUU source function by incorporating a tail to account for the contribution of secondary decay emissions, which cannot be accurately captured by BUU simulations. Resulting source function reproduces the features in the measured correlations. To illustrate our approach, we examine p-p correlations measured in Ar + Sc reactions at E/A = 80 MeV, considering both momentum-independent and momentum-dependent nuclear equations of state (EOS).

    nucl-th4 citations
  5. 05

    Contact potentials in presence of a regular finite-range interaction using dimensional regularization and the method

    David R. Entem🇪🇸 · Juan Nieves🇪🇸 · Jose Antonio Oller🇪🇸

    We solve the Lippman-Schwinger equation (LSE) with a kernel that includes a regular finite-range potential and additional contact terms with derivatives. We employ distorted wave theory and dimensional regularization, as proposed in Physics Letters B 568 (2003) 109. We analyze the spin singlet nucleon-nucleon wave as case of study, with the regular one-pion exchange (OPE) potential in this partial wave and up to (six derivatives) contact interactions. We discuss in detail the renormalization of the LSE, and show that the scattering amplitude solution of the LSE fulfills exact elastic unitarity and inherits the left-hand cut of the long-distance OPE amplitude. Furthermore, we proof that the LSE amplitude coincides with that obtained from the exact calculation, with the appropriate number and typology of subtractions to reproduce the effective range parameters taken as input to renormalize the LSE amplitude. The generalization to higher number of derivatives is straightforward.

    nucl-thhep-phPRD(2025)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE