Nuclear Theory·nucl-th

Monday·July 24, 2023

8 papers—3 primary·5 cross-listed

01
Dark matter effects on the properties of neutron stars: optical radii
Hong-Ming Liu🇨🇳 · Jin-Biao Wei🇨🇳 · Zeng-Hua Li🇨🇳 · G. F. Burgio🇮🇹 · H.-J. Schulze🇮🇹
We study the effects of dark matter on the properties of neutron stars by employing a DM-admixed model. The Brueckner-Hartree-Fock theory with realistic three-body forces and a generic bosonic self-interacting dark matter model describe the equations of state for nuclear matter and DM, respectively. We study the complete set of stable dark neutron stars and in particular the observable radii of these objects. A rich variety of stellar configurations is found and discussed in detail.
nucl-thPhys.Dark Univ.(2023)·32 citations
02
Hyperon-Nucleon Interaction Constrained by Light Hypernuclei
Marco Knöll🇩🇪 · Robert Roth🇩🇪
Ab initio structure calculations for p-shell hypernuclei have recently become accessible through extensions of nuclear many-body methods, such as the no-core shell model, in combination with hyperon-nucleon interactions from chiral effective field theory. However, the low-energy constants in these hyperon-nucleon interactions are poorly constraint due to the very limited amount of experimental scattering data available. We present a hyperon-nucleon interaction that is additionally constrained by experimental ground-state and spectroscopic data for selected p-shell hypernuclei and, thus, optimized for hypernuclear structure calculations. We show that the previous overestimation of the hyperon separation energies in the p-shell is remedied and discuss the significantly improved description of the $_{Λ}$ He isotopic chain. We further discuss the uncertainty quantification for hypernuclear observables on the many-body level, obtained through a novel machine-learning tool.
nucl-thPLB(2023)·13 citations
03
Stability of multicomponent Israel-Stewart-Maxwell theory for charge diffusion
Lorenzo Gavassino · Masoud Shokri
We obtain stability criteria for diffusive inviscid multicomponent Israel-Stewart hydrodynamics with and without background or dynamic electromagnetic fields. Our analysis is grounded on the maximum entropy principle, and it provides stability conditions that are valid around all thermodynamic equilibria, including rotating equilibria, charged equilibria, and equilibria in a background gravitational field. We prove that the electromagnetic part of the information current is stable and causal by construction and, therefore, the stability criteria found for Israel-Stewart theories of hydrodynamics automatically extend to similar formulations of magnetohydrodynamics.
nucl-thastro-ph.HEgr-qcPRD(2023)·13 citations
04
Reexamining constraints on neutron star properties from perturbative QCD
Dake Zhou🇺🇸
The implications of perturbative QCD (pQCD) calculations on neutron stars are carefully examined. While pQCD calculations above baryon chemical potentials $μ_{B} ≃ 2.4$ GeV demonstrate the potential of ruling out a wide range of neutron star equations of state (EOSs), such constraints only affect the most massive neutron stars in the vicinity of the Tolman-Oppenheimer-Volkoff (TOV) limit, resulting in constraints that are orthogonal to current or expected astrophysical bounds. In the most constraining scenario, pQCD considerations favor low values of the squared speed sound $C_{s}$ at high $μ_{B}$ relevant for the most massive neutron stars, but leave predictions of the radii and tidal deformabilities almost unchanged. Such considerations become irrelevant if the maximum speed of sound squared inside neutron stars does not exceed about $C_{s, max} ≃ 0.5$ , or if pQCD breaks down below $μ_{B} ≃ 2.9$ GeV. Furthermore, the large pQCD uncertainties preclude any meaningful bounds on the neutron star EOS at the moment. Interestingly, if pQCD predictions for the pressure at around $μ_{B} ≃ 2.5$ GeV are refined and found to be low ( $≲ 1.5$ GeV/fm $^{3}$ ), evidence for a soft neutron star inner core EOS in combination with the existence of two-solar-mass pulsars would indicate the presence of color superconductivity beyond neutron star densities. We point out that two-solar-mass pulsars place robust upper bounds on this non-perturbative effect and require the pairing gap to be less than $Δ_{CFL} ≲ 500$ MeV at $μ_{B} ≃ 2.5$ GeV.
↳ astro-ph.HEhep-phnucl-thPRC(2025)·19 citations
05
Synchronization effects on rest frame energy and momentum densities in the proton
Adam Freese🇺🇸 · Gerald A. Miller🇺🇸
We obtain two-dimensional relativistic densities and currents of energy and momentum in a proton at rest. These densities are obtained at surfaces of fixed light front time, which physically corresponds to using an alternative synchronization convention. Mathematically, this is done using tilted light front coordinates, which consist of light front time and ordinary spatial coordinates. In this coordinate system, all sixteen components of the energy-momentum tensor obtain clear physical interpretations, and the nine Galilean components reproduce results from standard light front coordinates. We find angular modulations in several densities that are absent in the corresponding instant form results, which are explained as optical effects arising from using fixed light front time when motion is present within the target. Additionally, transversely-polarized spin-half targets exhibit an energy dipole moment -- which evaluates to $- 1/4$ for all targets if the Belinfante EMT is used, but which is target dependent and vanishes for pointlike fermions if the asymmetric EMT is instead used.
↳ hep-phnucl-thPRD(2023)·16 citations
06
On the momentum broadening of in-medium jet evolution using a light-front Hamiltonian approach
Meijian Li🇪🇸 · Tuomas Lappi🇫🇮 · Xingbo Zhao🇨🇳 · Carlos A. Salgado🇪🇸
We have developed a non-perturbative light-front Hamiltonian formalism to simulate the real-time evolution of a quark state in a SU(3) colored medium, with a series of works. In this proceeding article, we focus on the transverse momentum broadening of an in-medium quark jet. We perform the numerical simulation of the quark jet evolution in the $∣ q ⟩ + ∣ q g ⟩$ Fock space at various medium densities. By analyzing the resulting jet light-front wavefunction, we extract the gluon emission rate and the non-eikonal quenching parameter. Additionally, we provide the analytical derivation of the eikonal expectation value of the quark-gluon state's transverse momentum for any color configuration and arbitrary spatial distribution. This study can help understand jet momentum broadening beyond the eikonal limit.
↳ hep-phnucl-thPoS(2024)·1 citation
07
The Generative Programs Framework
Mordecai Waegell🇺🇸 · Kelvin J. McQueen🇺🇸 · Emily C. Adlam🇺🇸
Recently there has been significant interest in using causal modelling techniques to understand the structure of physical theories. However, the notion of `causation' is limiting - insisting that a physical theory must involve causal structure already places significant constraints on the form that theory may take. Thus in this paper, we aim to set out a more general structural framework. We argue that any quantitative physical theory can be represented in the form of a generative program, i.e. a list of instructions showing how to generate the empirical data; the information-processing structure associated with this program can be represented by a directed acyclic graph (DAG). We suggest that these graphs can be interpreted as encoding relations of `ontological priority,' and that ontological priority is a suitable generalisation of causation which applies even to theories that don't have a natural causal structure. We discuss some applications of our framework to philosophical questions about realism, operationalism, free will, locality and fine-tuning.
↳ physics.hist-phgr-qchep-thnucl-th+13 citations
08
The role of the pion in the lineshape of the $X (3872)$
Angelo Esposito🇮🇹 · Davide Germani🇮🇹 · Alfredo Glioti🇫🇷 · Antonio D. Polosa🇮🇹 · Riccardo Rattazzi🇨🇭 · Michele Tarquini🇺🇸
We determine the contribution of long-range pion interactions to the $X (3872)$ dynamics, assuming it is a loosely bound $D^{0} D ˉ^{* 0}$ molecule. Our result is based on the distorted wave Born approximation in non-relativistic quantum mechanics. Despite their long-range nature, we find that pion interactions cannot produce a large and negative effective range. Nonetheless, they introduce imaginary parts. In particular, they contribute to the total decay width of the $X (3872)$ with a term associated with, but not precisely corresponding to, the $D^{*}$ width. Our approach can also be applied to the recently discovered $T_{cc}^{+}$ states.
↳ hep-phnucl-thPLB(2023)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE