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Nuclear Theory·nucl-th

Tuesday·October 8, 2024

12 papers—5 primary·7 cross-listed

All12Primary5Cross-lists7
  1. 06

    Accessing Generalized Parton Distributions through exclusive processes

    Goran Duplančić🇫🇷 · Saad Nabeebaccus🇭🇷 · Kornelija Passek-K.🇫🇷 · Bernard Pire🇭🇷 · Lech Szymanowski🇫🇷 · Samuel Wallon🇵🇱

    We review our results on a new class of exclusive processes, as a probe of both chiral-even and chiral-odd quark GPDs. We consider the exclusive photoproduction of a photon-meson pair, in the kinematics where the pair has a large invariant mass, described in the collinear factorization framework. We cover the whole kinematical range from medium energies in fixed target experiments to very large energies of colliders, by considering the experimental conditions of JLab 12-GeV, COMPASS, future EIC and LHC (in ultra-peripheral collisions) cases. Our analysis covers neutral and charged rho-mesons, as well as charged pions. The case of the rho-meson, depending on its polarization, provides access to either chiral-even or chiral-odd GPDs, at leading twist. We find that the order of magnitude of the obtained cross sections are sufficiently large for a dedicated experimental analysis to be performed, especially at JLab. Furthermore, we compute the linear photon beam polarization asymmetry, which we find to be sizeable, in the case of a longitudinally polarized -meson or of a charged pion. These predictions are obtained for both asymptotic distribution amplitude (DA) and holographic DA.

    ↳ hep-phnucl-thPoS(2025)·0 citations
  2. 07

    Impressions of Parton Distribution Functions

    Yang Yu🇨🇳 · Craig D. Roberts🇨🇳

    Parton distribution functions (DFs) have long been recognised as key measures of hadron structure. Today, theoretical prediction of such DFs is becoming possible using diverse methods for continuum and lattice analyses of strong interaction (QCD) matrix elements. Recent developments include a demonstration that continuum and lattice analyses yield mutually consistent results for all pion DFs, with behaviour on the far valence domain of light-front momentum fraction that matches QCD expectations. Theory is also delivering an understanding of the distributions of proton mass and spin amongst its constituents, which varies, of course, with the resolving scale of the measuring probe. Aspects of the pion DF and proton spin developments are sketched herein, along with some novel perspectives on gluon and quark orbital angular momentum.

    ↳ hep-phhep-exhep-latnucl-ex+1Chin.Phys.Lett.(2024)·21 citations
  3. 08

    Detecting spacelike vacuum entanglement at all distances and promoting negativity to a necessary and sufficient entanglement measure in many-body regimes

    Boyu Gao🇺🇸 · Natalie Klco🇺🇸

    Though known to be present, the accessibility of spacelike vacuum entanglement capable of being a fundamental resource for quantum information processing has remained in question at distances beyond the scale of vacuum fluctuations in massive fields. For a broad subclass of physical many-body mixed Gaussian states, including the free scalar field vacuum, the logarithmic negativity is here shown to be a necessary and sufficient measure of entanglement and to be entirely accessible by pairs of single-mode detectors in the continuum. By deriving exact and optimal detection profiles, entanglement resources in the massive field are demonstrated to be available at all distances.

    ↳ quant-phhep-latnucl-thPRA(2025)·6 citations
  4. 09

    Effect of theory of gravity on the properties of strange quark stars

    Suman Pal🇮🇳 · Gargi Chaudhuri🇮🇳

    In this study, we investigate strange quark stars within the framework of modified gravity, where represents the Ricci scalar and denotes the trace of the energy-momentum tensor, specifically defined as . The equation of state is obtained with the different forms of the MIT bag model and quark mass model with medium effects and self-consistent thermodynamical treatment. We find that negative values of significantly increase both the mass and radius of the quark star. The inclusion of helps to satisfy recent the astrophysical constraints on the mass-radius relationship. We have also constrained the values of for each EoS, based on the observed maximum mass and corresponding radius, demonstrating that the inclusion of this parameter helps to address the challenges posed by both the GW190814 event and NICER observations of PSR J0030+0451. We also observe that the inclusion of gravity leads to an increase in both the maximum mass, by about , and the corresponding radius, by approximately (1.5-2.0)~\text{km}, depending on the chosen equation of state.

    ↳ gr-qcastro-ph.HEnucl-th1 citation
  5. 10

    Persistence of charmed hadrons in QGP from lattice QCD

    Sipaz Sharma🇩🇪

    We study the nature of charm degrees of freedom near the chiral crossover based on lattice QCD calculations of the second and fourth-order cumulants of charm fluctuations, and their correlations with net baryon number, electric charge, and strangeness fluctuations. We show that below the chiral crossover temperature, , the thermodynamics of charm can be very well understood in terms of charmed hadrons. We present evidence that above , however, charm quark-like excitations emerge as new degrees of freedom contributing to the partial charm pressure. Nonetheless, up to temperatures as high as 175 MeV, charmed hadron-like excitations significantly contribute to the partial charm pressure.

    ↳ hep-lathep-phnucl-thInt.J.Mod.Phys.A(2025)·4 citations
  6. 11

    Azimuthal Anisotropy Scaling for Identified Mesons and Baryons: Insights into Medium Transport Properties, Equation of State and Hadronic Re-scattering

    Roy A. Lacey (Department of Chemistry, Stony Brook University, Stony Brook, NY, USA)🇺🇸

    Scaling functions for the centrality and transverse momentum dependence of \(v_2(p_T,\text{cent})\) and \(v_3(p_T,\text{cent})\) are constructed for identified mesons and baryons in Pb+Pb (\(\sqrt{s_{NN}}=2.76,\ 5.02\)~TeV), Xe+Xe (5.44~TeV), and Au+Au (0.2~TeV) collisions. These species-resolved functions capture the interplay of initial geometry, viscous attenuation, radial flow, partonic energy loss, and hadronic re-scattering across both flow- and quenching-dominated regimes. The systematic growth of the radial-flow parameter \(\zeta_{\rm rf}\) with multiplicity and beam energy provides direct empirical constraints on the equation of state (EOS) of hot QCD matter. The extracted parameters also yield differential constraints on the specific shear viscosity \(\eta/s\), the jet-quenching parameter \(\hat{q}\), and late-stage hadronic dynamics. LHC systems exhibit low \(\eta/s\), strong radial flow, and negligible re-scattering at high energy density, whereas Au+Au at RHIC energy shows even lower \(\eta/s\), weaker radial flow, finite re-scattering, and reduced energy density. The coexistence of strong radial flow at low \(p_T\) and significant jet suppression at high \(p_T\) emerges as a defining hallmark of QGP formation, establishing the framework as a quantitative probe of QGP transport properties and EOS stiffness.

    ↳ nucl-exhep-exhep-phnucl-th2 citations
  7. 12

    Unraveling the Energy-Energy Correlators for Heavy Flavor Tagged Jets in pp, p+Pb and Pb+Pb Collisions

    Ke-Ming Shen🇨🇳 · Shi-Yong Chen🇨🇳 · Yu-Jie Huang🇨🇳 · Wei Dai🇨🇳 · Ben-Wei Zhang🇨🇳

    In this study, energy-energy correlator (EEC) distributions for the , -tagged, inclusive, and the PYTHIA generated pure quark jets are computed in pp, p+Pb, and Pb+Pb collisions at \sqrts =5.02 TeV for a same jet transverse momentum interval 15-30 GeV. We find the number of particles per jet determines the height of the EEC distribution in pp baseline. The averaged energy weight distribution resulted in a shift of the originally larger angular distributed particle distribution to a smaller RL, thereby obtaining an EEC distribution. The EEC distributions for all quark-tagged jets in A+A exhibit a noticeable shift towards larger RL region, suggesting that the jets will be more widely distributed compared to those in pp collisions. The jet quenching effect will cause the pair angular distribution to shift towards larger values and increase the number of particles per jet. This redistribution of energy within the jets suggests that the already reduced jet energy is redistributed among a larger number of particles, leading to a reduced energy weight per pair. The enhancement of the number of particles per jet and the reduced averaged energy weight interplay with each other to form the medium modification of EEC.

    ↳ hep-phnucl-th3 citations

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first authorsco-authorsvia INSPIRE