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Nuclear Theory·nucl-th

Tuesday·September 14, 2021

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    Off-of-equilibrium effects on Kurtosis Along Strangeness-Neutral Trajectories

    Travis Dore🇺🇸 · Jamie Karthein🇺🇸 · Debora Mroczek🇺🇸 · Paolo Parotto🇩🇪 · Jacquelyn Noronha-Hostler🇺🇸 · Claudia Ratti🇺🇸

    The Beam Energy Scan program at the Relativistic Heavy Ion Collider (RHIC) is searching for the QCD critical point. The main signal for the critical point is the kurtosis of the distribution of proton yields obtained on an event-by-event basis where one expects a peak at the critical point. However, its exact behavior is still an open question due to out-of-equilibrium effects and uncertainty in the equation of state. Here we use a simplistic hydrodynamic model that enforces strangeness-neutrality, selecting trajectories that pass close to the critical point. We vary the initial conditions to estimate the effect of out-of-equilibrium hydrodynamics on the kurtosis signal.

    nucl-thhep-phnucl-exEPJ Web Conf.(2022)·4 citations
  2. 02

    Transverse momentum analysis of collective motion in relativistic nuclear collisions

    P. Danielewicz🇺🇸 · G. Odyniec (LBL)🇺🇸

    Novel transverse-momentum technique is used to analyse charged-particle exclusive data for collective motion in the Ar+KCl reaction at 1.8 GeV/nucl. Previous analysis of this reaction, employing the standard sphericity tensor, revealed no significant effect. In the present analysis, collective effects are observed, and they are substantially stronger than in the Cugnon cascade model, but weaker than in the hydrodynamical model.

    nucl-thnucl-exPLB(1985)·504 citations
  3. 03

    Fock space dualities

    K. Neergård

    Several cases of Fock space duality occurring in the theory of many-body systems in general and nuclei in particular are discussed. All of them are special cases of a general duality theorem proved in mathematics by Howe in the 1970s. Dualities on a fermion Fock space between orthogonal Lie algebras and related groups, including an o-Pin duality recently discovered by the author, present a nice, symmetric pattern.

    nucl-thBulg.J.Phys.(2021)·2 citations
  4. 04

    Comparison of different relativistic models applied to dense nuclear matter

    R. Somasundaram🇫🇷 · J. Margueron🇫🇷 · G. Chanfray🇫🇷 · H. Hansen🇫🇷

    We explore three different classes of relativistic approaches applied to the description of dense nuclear matter: a Walecka-type relativistic mean field model (RMF), an extension including an effective chiral potential (RMF-C) and a further extension with a chiral potential and confinement effects (RMF-CC). The parameters of the latter are controlled by fundamental properties such as the chiral potential, Lattice-QCD predictions, the quark sub-structure, as well as empirical properties at nuclear matter saturation. While these models are calibrated to the same properties at saturation density, they differ in their predictions as the density increases. We take care of parameter uncertainties and propagate them to our predictions for symmetric nuclear matter by employing Bayesian statistics. We show that RMF and RMF-C share common features as the density increases, while RMF-CC behaves differently. For instance, the scalar field at reaches MeV for RMF-CC while it is larger than MeV for RMF and RMF-C. Interestingly, we also show that, by fixing the coupling constant from the quark structure of the nucleon, these three models reproduce only half of the empirical symmetry energy.

    nucl-thEPJA(2022)·11 citations
  5. 05

    Quenching of Gamow-Teller strengths and two particle -- two hole configurations

    Danilo Gambacurta🇮🇹 · Marcella Grasso🇫🇷

    We apply the charge-exchange subtracted second random-phase approximation (SSRPA), based on Skyrme functionals, to investigate Gamow-Teller resonances in several closed-shell and closed-subshell nuclei, located in different regions of the nuclear chart. After having discussed the SSRPA findings obtained within different approximation schemes in Ca, we compare our results with {\it{ab-initio}} coupled-cluster predictions available for C and O isotopes, where two-body currents are included. Our integrated strenghts, obtained by using one-body transition operators, are lower compared to the corresponding {\it{ab-initio}} results. This indicates that, within our model, quenching effects are mainly driven by the inclusion of two particle - two hole configurations and that the role of a two-body contribution in the transition operator is less important than in the coupled-cluster approach. By analyzing heavier nuclei, Zr and Sn, we confirm the same conclusions that we have recently drawn for Ca: the inclusion of two particle - two hole configurations is very effective in our model for providing strengths which are significantly more quenched than in other theoretical models and, thus, in better agreement with the experimental measurements. This occurs because two particle - two hole configurations have a density which strongly increases with the excitation energy. Their inclusion thus pushes a significant amount of the strength to higher energies, compared to what happens in other theoretical models, reducing in this way the cumulative sum of the strength up to excitation energies around 20-30 MeV.

    nucl-thnucl-exPRC(2022)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE