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Nuclear Theory·nucl-th

Friday·December 10, 2021

7 papers—1 primary·6 cross-listed

All7Primary1Cross-lists6
  1. 01

    Non-equilibrium cumulants within model A from crossover to first-order phase transition side

    Lijia Jiang🇨🇳 · Jingyi Chao🇨🇳

    We study the non-equilibrium cumulants of the chiral order parameter field ({\sigma} field) in different phase transition scenarios via Langevin dynamics. Cumulants up to fourth-order have been calculated based on the spacetimedependent {\sigma} configurations from the event-by-event numerical simulations. By limiting the cooling of the system in a Hubble-like way, the out-of-equilibrium cumulants illustrate clear memory effects during the evolution. Both the signs and the magnitudes of the high-order cumulants differ from the equilibrium ones below the phase transition temperature. Especially, the dynamical cumulants grow more intensively from the first-order phase transition side than they do from the crossover side. In addition, analysis of the high-order offequilibrium cumulants on the hypothetical freeze-out lines present non-monotonic curves in the large chemical potential region.

    nucl-thhep-phEPJA(2023)·8 citations
  2. 02

    Correlating confinement to topological fluctuations near the crossover transition in QCD

    Rasmus N. Larsen🇳🇴 · Sayantan Sharma🇮🇳 · Edward Shuryak🇺🇸

    We show the existence of strong (anti)correlations between the topological hot spots and the local values of the trace of the Polyakov loop in flavor QCD with physical quark mass, in the vicinity of the crossover transition corresponding to the simultaneous restoration of chiral symmetry and deconfinement. Using sophisticated lattice techniques, we have carefully identified the topological hot spots using quark zero modes and measured the short-distance fluctuations of the Polyakov loop about them, showing how the latter is repelled quite strongly around the peak of the zero modes. Though we could explain some aspects of these correlations within the instanton-dyon picture, our work sets the stage for a larger goal towards a systematic study of the role of different topological species that interact with the Polyakov loop, establishing the strong connection between topology and confinement.

    ↳ hep-lathep-thnucl-thPRD(2022)·5 citations
  3. 03

    Toward a resolution of the NN controversy

    Amy Nicholson🇺🇸 · Evan Berkowitz🇩🇪 · John Bulava🇩🇰 · Chia Cheng Chang🇺🇸 · M.A. Clark🇺🇸 · Andrew D. Hanlon🇺🇸 · Ben Horz🇺🇸 · Dean Howarth🇺🇸 · Christopher Korber🇩🇪 · Wayne Tai Lee🇺🇸 · Aaron S. Meyer🇺🇸 · Henry Monge-Camacho🇨🇷 and 4 other authors

    Lattice QCD calculations of two-nucleon interactions have been underway for about a decade, but still haven't reached the pion mass regime necessary for matching onto effective field theories and extrapolating to the physical point. Furthermore, results from different methods, including the use of the Luscher formalism with different types of operators, as well as the HALQCD potential method, do not agree even qualitatively at very heavy pion mass. We investigate the role that different operators employed in the literature may play on the extraction of spectra for use within the Luscher method. We first explore expectations from Effective Field Theory solved within a finite volume, for which the exact spectrum may be computed given different physical scenarios. We then present preliminary lattice QCD results for two-nucleon spectra calculated using different operators on a common lattice ensemble.

    ↳ hep-latnucl-thPoS(2022)·13 citations
  4. 04

    Deciphering the role of multiple scatterings and time delays in the in-medium emission process

    Carlota Andres🇫🇷 · Liliana Apolinario🇵🇹 · Fabio Dominguez🇪🇸 · Marcos Gonzalez Martinez🇪🇸 · Carlos A. Salgado🇪🇸

    In this work we use the all-order resummed solution of the BDMPS-Z spectrum to shed light on the dynamics that controls the in-medium radiation process for each kinematical regime. We find that multiple scatterings are essential to correctly describe the radiation process both in the low and mid-energy regime, while in the high-energy region one single hard scattering is enough. Furthermore, we compute the all-order spectrum when the medium is produced with a time delay with respect to the hard process in which the parent parton was created. The propagation of the hard parton though vacuum before the medium formation induces extra medium-induced radiation which might have an impact on phenomenological analyses.

    ↳ hep-phnucl-thPoS(2022)·0 citations
  5. 05

    Accessing subnuclear fluctuations and saturation with multiplicity dependent production in p+p and p+Pb collisions

    Farid Salazar🇺🇸 · Björn Schenke🇺🇸 · Alba Soto-Ontoso🇫🇷

    We study the production of vector mesons as a function of charged hadron multiplicity in p+p and p+Pb collisions at LHC energies. We employ the color glass condensate framework, using running coupling Balitsky-Kovchegov evolved dipole amplitudes, to compute gluon and -pair production. We use fragmentation functions to obtain charged hadrons, and explore two different hadronization schemes for the : non-relativistic quantum chromodynamics and the improved color evaporation model. In our framework, event-by-event multiplicity fluctuations of both hadrons and are driven by geometric and saturation scale normalization fluctuations. Studying the correlation between and hadron multiplicity, we show that the characteristic difference between forward and backward rapidity in p+Pb collisions is a result of different degrees of saturation probed at different rapidities. We demonstrate that experimental data on heavy-flavor production as a function of event activity provide stringent constraints on the fluctuating proton structure.

    ↳ hep-phnucl-thPLB(2022)·23 citations
  6. 06

    Analysis of virtual meson production in solvable (1+1) dimensional scalar field theory

    Yongwoo Choi🇰🇷 · Ho-Meoyng Choi🇰🇷 · Chueng-Ryong Ji🇺🇸 · Yongseok Oh🇰🇷

    Light-front time-ordered amplitudes are investigated in the virtual scalar meson production process in (1+1) dimensions using the solvable scalar field theory extended from the conventional Wick-Cutkosky model. There is only one Compton form factor (CFF) in the (1+1) dimensional computation of the virtual meson production process, and we compute both the real and imaginary parts of the CFF for the entire kinematic regions of and . We then analyze the contribution of each and every light-front time-ordered amplitude to the CFF as a function of and . In particular, we discuss the significance of the "cat's ears" contributions for gauge invariance and the validity of the "handbag dominance" in the formulation of the generalized parton distribution (GPD) function used typically in the analysis of deeply virtual meson production processes. We explicitly derive the GPD from the "handbag" light-front time-ordered amplitudes in the limit and verify that the integrations of the GPD over the light-front longitudinal momentum fraction for the DGLAP and ERBL regions correspond to the valence and nonvalence contributions of the electromagnetic form factor that we have recently reported [Phys. Rev. D , 076002 (2021)]. We also discuss the correspondence of the GPD to the parton distribution function for the analysis of the deep inelastic lepton-hadron scattering process and the utility of the new light-front longitudinal spatial variable .

    ↳ hep-phnucl-thPRD(2022)·1 citation
  7. 07

    Revisiting NLO QCD corrections to total inclusive J/psi and Upsilon photoproduction cross sections in lepton-proton collisions

    Alice Colpani Serri🇫🇷 · Yu Feng🇨🇳 · Carlo Flore🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Melih A. Ozcelik🇫🇷 · Hua-Sheng Shao🇫🇷 · Yelyzaveta Yedelkina🇫🇷

    We revisit inclusive J/psi and Upsilon photoproduction at lepton-hadron colliders, namely in the limit when the exchanged photon is quasi real. Our computation includes the next-to-leading-order (NLO) alpha_s corrections to the leading-order contributions in v. Similarly to the case of NLO charmonium-hadroproduction processes, the resulting cross sections obtained in the MS-bar factorisation scheme are sometimes found to be negative. We show that the scale-fixing criteria which we derived in a previous study of eta(c) production successfully solves this problem from the EicC all the way up to the FCC-eh energies. We then elaborate on how to study a scale uncertainty akin to that derived by scale variations when one fixes a scale. In turn, we investigate where both J/psi and Upsilon photoproduction could be used to improve our knowledge of gluon content of the proton at scales as low as a couple of GeV.

    ↳ hep-phhep-exnucl-exnucl-thPLB(2022)·33 citations

Affiliations

first authorsco-authorsvia INSPIRE