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Nuclear Theory·nucl-th

Monday·June 24, 2024

11 papers—7 primary·4 cross-listed

All11Primary7Cross-lists4
  1. 08

    Anomalous thresholds in form factors

    Simon Mutke🇩🇪 · Martin Hoferichter🇨🇭 · Bastian Kubis🇩🇪

    We study the effects of anomalous thresholds on the non-local form factors describing the hadronization of the light-quark contribution to transitions. Starting from a comprehensive discussion of anomalous thresholds in the triangle loop function for different mass configurations, we detail how the dispersion relation for intermediate states is affected by contour deformations mandated by the anomalous branch points. Phenomenological estimates of the size of the anomalous contributions to the form factors are provided with couplings determined from measured branching fractions and Dalitz plot distributions. Our key finding is that anomalous effects are suppressed on the resonance, while off-peak the effects can become as large as of the full (light-quark-loop induced) non-local form factors. We comment on future generalizations towards higher intermediate states and the charm loop, outlining how the dispersive framework established in this work could help improve the non-local form factors needed as input for a robust interpretation of decays.

    ↳ hep-phhep-exnucl-thJHEP(2024)·22 citations
  2. 09

    Gluon radiation inside a flowing medium

    Matvey V. Kuzmin🇷🇺 · Xoán Mayo López🇪🇸

    We compute the spectrum of gluons emitted by a highly energetic quark inside a flowing QCD medium, focusing on the soft gluon limit at first order in the opacity expansion. Specifically, we derive the leading energy-suppressed corrections to the double differential final parton distribution, and show that they are substantial for both static and flowing matter. In particular, we demonstrate that the corrections due to the transverse flow become large even at moderate energies and flow velocities, affecting drastically both the shape and magnitude of the spectrum. We observe that the final transverse momentum of the emitted gluon tends to align along the flow direction, resulting in a non-trivial azimuthal distribution. These results can be directly implemented into the estimation of multiple observables to get a better understanding of the jet-medium interaction processes in HICs.

    ↳ hep-phnucl-thPRD(2026)·17 citations
  3. 10

    Electric Conductivity of QCD Matter and Dilepton Spectra in Heavy-Ion Collisions

    Ralf Rapp🇺🇸

    The electric conductivity, , is a fundamental transport coefficient of QCD matter that can be related to the zero-energy limit of the electromagnetic (EM) spectral function at vanishing 3-momentum in the medium. The EM spectral function is also the central quantity to describe the thermal emission rates and pertinent spectra of photon and dilepton radiation in heavy-ion collisions. Employing a model for dilepton rates that combines hadronic many-body theory with nonperturbative QGP emission constrained by lattice-QCD which describes existing dilepton measurements in heavy-ion collisions, we investigate the sensitivity of low-mass dilepton spectra in Pb-Pb collisions at the LHC to . In particular, we disentangle the contributions from QGP and hadronic emission, and identify signatures that can help to extract from high-precision experimental data expected to be attainable with future detector systems at the LHC.

    ↳ hep-phnucl-exnucl-thPRC(2024)·12 citations
  4. 11

    Inference of neutron-star properties with unified crust-core equations of state for parameter estimation

    P. J. Davis🇫🇷 · H. Dinh Thi🇫🇷 · A. F. Fantina🇫🇷 · F. Gulminelli🇫🇷 · M. Oertel🇫🇷 · L. Suleiman🇫🇷

    Relating different global neutron-star (NS) properties, such as tidal deformability and radius, or mass and radius, requires an equation of state (EoS). Determining the NS EoS is therefore not only the science goal of a variety of observational projects, but it also enters in the analysis process; for example, to predict a NS radius from a measured tidal deformability via gravitational waves (GW) during the inspiral of a binary NS merger. To this aim, it is important to estimate the theoretical uncertainties on the EoS, one of which is the possible bias coming from an inconsistent treatment of the low-density region; that is, the use of a so called non-unified NS crust. We propose a numerical tool allowing the user to consistently match a nuclear-physics informed crust to an arbitrary high-density EoS describing the core of the star. We introduce an inversion procedure of the EoS close to saturation density that allows users to extract nuclear-matter parameters and extend the EoS to lower densities in a consistent way. For the treatment of inhomogeneous matter in the crust, a standard approach based on the compressible liquid-drop (CLD) model approach was used in our work. A Bayesian analysis using a parametric agnostic EoS representation in the high-density region is also presented in order to quantify the uncertainties induced by an inconsistent treatment of the crust. We show that the use of a fixed, realistic-but-inconsistent model for the crust causes small but avoidable errors in the estimation of global NS properties and leads to an underestimation of the uncertainties in the inference of NS properties. Our results highlight the importance of employing a consistent EoS in inference schemes. The numerical tool that we developed to reconstruct such a thermodynamically consistent EoS, CUTER, has been tested and validated for use by the astrophysical community.

    ↳ astro-ph.HEnucl-thAstron.Astrophys.(2024)·39 citations

Affiliations

first authorsco-authorsvia INSPIRE