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Nuclear Theory·nucl-th

Wednesday·February 21, 2024

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 01

    [Submitted on 20 Feb 2024]

    Intruder band mixing in an ab initio description of 12Be

    Anna E. McCoy · Mark A. Caprio · Pieter Maris · Patrick J. Fasano

    The spectrum of 12Be exhibits exotic features, e.g., an intruder ground state and shape coexistence, normally associated with the breakdown of a shell closure. While previous phenomenological treatments indicated the ground state has substantial contributions from intruder configurations, it is only with advances in computational abilities and improved interactions that this intruder mixing is observed in ab initio no-core shell model (NCSM) predictions. In this work, we extract electromagnetic observables and symmetry decompositions from the NCSM wave functions to demonstrate that the low-lying positive parity spectrum can be explained in terms of mixing of rotational bands with very different intrinsic structure coexisting within the low-lying spectrum. These observed bands exhibit an approximate SU(3) symmetry and are qualitatively consistent with Elliott model predictions.

    Comments:
    10 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2402.12606 [pdf]
    PLB(2024)·16 citations
  2. 02

    [Submitted on 20 Feb 2024]

    The influence of hadronic rescatterings on the net-baryon number fluctuations

    Qian Chen · Rui Wen · Shi Yin · Wei-jie Fu · Zi-Wei Lin · Guo-Liang Ma

    Fluctuations of conserved charges, such as the net-baryon number fluctuations, are influenced by different dynamical evolution processes. In this paper, we investigate the influence of hadronic rescatterings on different orders of cumulants of the net-baryon number distribution. At the start of hadronic rescatterings, we introduce net-baryon number distributions reconstructed based on net-baryon cumulants of different orders obtained from computation in functional renormalization group (FRG), where the distributions were constructed using the maximum entropy method. This way we introduce the critical fluctuations of Quantum Chromodynamics (QCD) into the AMPT model. Firstly, we find that hadronic rescatterings have distinct effects on cumulant ratios of different orders for the net-baryon number. Secondly, we observe that the effect of hadronic rescatterings is more significant for critical fluctuations than dynamical fluctuations, because the two-, three- and four-particle correlation functions due to critical fluctuations are weakened more significantly by hadronic rescatterings.

    Comments:
    10 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2402.12823 [pdf]
    5 citations
  3. 03

    [Submitted on 20 Feb 2024]

    Effects of incompressibility in heavy-ion collisions at intermediate energies

    Xiao-Xiao Long🇨🇳 · Gao-Feng Wei🇨🇳

    Within the possible least uncertainty on the nuclear incompressibility , we examine effects of in heavy-ion collisions at intermediate energies. Based on simulations of Au + Au collision at 400 MeV/nucleon using an isospin- and momentum-dependent transport model, we find that the incompressibility indeed affects significantly the attainable density in central regions, and thus the particle productions and/or distributions at final states, e.g., nucleon rapidity distributions and yields of charged pions. Nevertheless, through examining the free neutron over proton ratios , the neutron-proton differential transverse and directed flows as well as the charged pion ratio and its kinetic energy distribution, we find that these observables are less affected by the uncertainty of , but mainly sensitive to the slope of symmetry energy at the saturation density. We also compare and discuss our results with the corresponding data.

    Comments:
    7 pages, 8 figures. Accepted for publication in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2402.12912 [pdf]
    PRC(2024)·9 citations
  4. 04

    [Submitted on 20 Feb 2024]

    Causal and Stable Relativistic Hydrodynamic Fluctuations

    Nicki Mullins · Mauricio Hippert · Jorge Noronha · Lorenzo Gavassino

    When two nuclei collide close to the speed of light, a fluid state known as the quark-gluon plasma is formed. Attempts to understand the dynamics of this fluid have generated significant research into dissipative relativistic fluid dynamics. The fluctuation-dissipation theorem implies that any dissipative dynamical system will also experience thermal fluctuations; however, such fluctuations are not typically included in the modeling of the quark-gluon plasma. This work discusses a new method of determining whether a hydrodynamic framework is consistent with thermal fluctuations. We develop a new method for calculating the noise correlator of relativistic hydrodynamic systems and apply it to Israel-Stewart theory in a general hydrodynamic frame.

    Comments:
    4 pages. Contribution to the proceedings of the 9th Workshop for Young Scientists on the Physics of Ultra-relativistic Nucleus-Nucleus Collisions (Hot Quarks 2022)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2402.13119 [pdf]
    0 citations
  5. 05

    [Submitted on 20 Feb 2024]

    Assessing Correlated Truncation Errors in Modern Nucleon-Nucleon Potentials

    P. J. Millican🇺🇸 · R. J. Furnstahl🇺🇸 · J. A. Melendez🇺🇸 · D. R. Phillips🇸🇪 · M. T. Pratola🇺🇸

    We test the BUQEYE model of correlated effective field theory (EFT) truncation errors on Reinert, Krebs, and Epelbaum's semi-local momentum-space implementation of the chiral EFT (EFT) expansion of the nucleon-nucleon (NN) potential. This Bayesian model hypothesizes that dimensionless coefficient functions extracted from the order-by-order corrections to NN observables can be treated as draws from a Gaussian process (GP). We combine a variety of graphical and statistical diagnostics to assess when predicted observables have a EFT convergence pattern consistent with the hypothesized GP statistical model. Our conclusions are: First, the BUQEYE model is generally applicable to the potential investigated here, which enables statistically principled estimates of the impact of higher EFT orders on observables. Second, parameters defining the extracted coefficients such as the expansion parameter must be well chosen for the coefficients to exhibit a regular convergence pattern -- a property we exploit to obtain posterior distributions for such quantities. Third, the assumption of GP stationarity across lab energy and scattering angle is not generally met; this necessitates adjustments in future work. We provide a workflow and interpretive guide for our analysis framework, and show what can be inferred about probability distributions for , the EFT breakdown scale , the scale associated with soft physics in the EFT potential , and the GP hyperparameters. All our results can be reproduced using a publicly available Jupyter notebook, which can be straightforwardly modified to analyze other EFT NN potentials.

    Comments:
    29 pages, 33 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Data Analysis, Statistics and Probability (physics.data-an)
    arXiv:
    2402.13165 [pdf]
    PRC(2024)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE