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Nuclear Theory·nucl-th

Monday·September 4, 2023

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 01

    Calculation of microscopic nuclear level densities based on covariant density functional theory

    Kun-Peng Geng · Peng-Xiang Du · Jian Li · Dong-Liang Fang

    A microscopic method for calculating nuclear level density (NLD) based on the covariant density functional theory (CDFT) is developed. The particle-hole state density is calculated by combinatorial method using the single-particle levels schemes obtained from the CDFT. Then the level densities are obtained by taking into account collective effects such as vibration and rotation. Our results are compared with those from other NLD models, including phenomenological, microstatistical, and non-relativistic HFB combinatorial models. The comparison suggests that the general trends among these models are basically the same, except for some deviations from different NLD models. In addition, the NLDs of the CDFT combinatorial method with normalization are compared with experimental data, including the observed cumulative number of levels at low excitation energy and the measured NLDs. Compared with the existing experimental data, the CDFT combinatorial method can give reasonable results.

    nucl-thNucl.Sci.Tech.(2023)·17 citations
  2. 02

    O spectral function from coupled-cluster theory: applications to lepton-nucleus scattering

    Joanna E. Sobczyk🇩🇪 · Sonia Bacca🇩🇪

    We calculate the O spectral function by combining coupled-cluster theory with a Gaussian integral transform and by expanding the integral kernel in terms of Chebyshev polynomials to allow for a quantification of the theoretical uncertainties. We perform an analysis of the spectral function and employ it to predict lepton-nucleus scattering. Our results well describe the O electron scattering data in the quasi-elastic peak for momentum transfers MeV and electron energies up to 1.2 GeV, extending therefore the so-called first principles approach to lepton-nucleus cross sections well into the relativistic regime. To prove the applicability of this method to neutrino-nucleus cross sections, we implement our O spectral functions in the NuWro Monte Carlo event generator and provide a comparison with recently published T2K neutrino data.

    nucl-thhep-phPRC(2024)·16 citations
  3. 03

    Dilepton polarization as a signature of plasma anisotropy

    Maurice Coquet🇫🇷 · Xiaojian Du🇫🇷 · Jean-Yves Ollitrault🇪🇸 · Soeren Schlichting🇫🇷 · Michael Winn🇩🇪

    We propose the angular distribution of lepton pairs produced in ultrarelativistic heavy-ion collisions as a probe of thermalization of the quark-gluon plasma. We focus on dileptons with invariant masses large enough that they are produced through quark-antiquark annihilation in the early stages of the collision. The angular distribution of the lepton in the rest frame of the pair then reflects the angular distribution of quark momenta. At early times, the transverse pressure of the quark-gluon plasma is larger than its longitudinal pressure as a result of the fast longitudinal expansion, which results in an oblate lepton distribution. By contrast, direct (Drell-Yan) production by quarks and antiquarks from incoming nuclei, whose momenta are essentially longitudinal, results in a prolate distribution. As the invariant mass increases, Drell-Yan gradually becomes the dominant source of dilepton production, and the lepton distribution evolves from oblate to prolate. The invariant mass at which the transition occurs is highly sensitive to the equilibration time of the quark-gluon plasma or, equivalently, the shear viscosity over entropy ratio in the early stages of the collision.

    nucl-thhep-exhep-phnucl-exPRL(2024)·27 citations
  4. 04

    Bayesian location of the QCD critical point from a holographic perspective

    Mauricio Hippert🇺🇸 · Joaquin Grefa🇺🇸 · T. Andrew Manning🇺🇸 · Jorge Noronha🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸 · Israel Portillo Vazquez🇺🇸 · Claudia Ratti🇺🇸 · Romulo Rougemont🇧🇷 · Michael Trujillo🇺🇸

    A fundamental question in QCD is the existence of a phase transition at large doping of quarks over antiquarks. We present the first prediction of a QCD critical point (CP) from a Bayesian analysis constrained by first principle results at zero doping. We employ the gauge/gravity duality to map QCD onto a theory of dual black holes. Predictions for the CP location in different realizations of the model overlap at one sigma. Even if many prior samples do not include a CP, one is found in nearly 100\% of posterior samples, indicating a strong preference for a CP.

    nucl-thhep-phhep-thnucl-exPRD(2024)·121 citations

Affiliations

first authorsco-authorsvia INSPIRE