PaperPanorama

Nuclear Theory·nucl-th

Friday·September 27, 2019

9 papers7 primary·2 cross-listed

  1. 01

    Bayesian truncation errors in equations of state of nuclear matter with chiral nucleon-nucleon potentials

    Jinniu Hu · Peiyu Wei · Ying Zhang

    The truncation errors in equations of state (EOSs) of nuclear matter derived from the chiral nucleon-nucleon () potentials at different expansion orders are analyzed by a Bayesian model. These EOSs are expanded as functions of a dimensionless parameter, , which is determined by Fermi momentum, and breakdown scale, . The degree-of-belief (DoB) intervals predicted by the chiral effective field theory are calculated within the corresponding expansion coefficients and the specific prior probability distribution functions in terms of Bayes theorem. The truncation errors of EOSs, generated by the DoB intervals, exhibit good order-by-order convergences with different chiral expansion order potentials. When DoB is considered as credibility, i.e., confidence interval, the truncation errors of binding energy per nucleon in symmetric nuclear matter and pure neutron matter are consistent with the results given by a simple error analysis method proposed by Epelbaum, {\it et al.} Finally, the reasonable values of the breakdown scale in nuclear matter are discussed through consistency checks of Bayesian method based on the calculations of success rate.

    nucl-thPLB(2019)·11 citations
  2. 02

    The ANL-Osaka Partial-Wave Amplitudes of and Reactions

    H. Kamano🇯🇵 · T.-S. H. Lee🇺🇸 · S.X. Nakamura🇨🇳 · T. Sato🇯🇵

    The determination of the Argonne National Laboratory-Osaka University (ANL-Osaka) Partial-Wave Amplitudes (PWA) of and Reactions is reviewed. The predicted PWA are presented on a web page (https://www.phy.anl.gov/theory/research/anl-osaka-pwa). The formulas are given for using the predicted PWA to calculate the cross sections of (1) meson-baryon () scattering with , (2) two-pion production , (3) Meson photoproduction , (4) Pion electroproduction , (5) inclusive . We also present sample results from our fits to the data.

    nucl-thhep-exhep-phnucl-ex23 citations
  3. 03

    The collective excitation of nuclear matter in a bosonized Landau Fermi liquid model

    Bao-Xi Sun

    The collective excitation of nuclear matter is analyzed in a bosonized Landau Fermi liquid model. When the nonlinear self-interacting terms of scalar mesons are included in Walecka model, the collective excitation energy of nuclear matter can be obtained self-consistently, and the calculation results are consistent with the corresponding experimental data of the nucleus when the quantum number of the orientation of the total spin is zero. The cases with the nonzero values are also studied, and it is found that the collective excitation energy of nuclear matter decreases with the absolute value of increasing when the total spin is conserved. Moreover, four kinds of collective excitation modes of nuclear matter are discussed when the isospin and spin of nucleons are taken into account. The direct interaction between two nucleons near Fermi surface only changes the effective nucleon mass and Fermi velocity, while the exchange interaction plays an critical role in the collective excitation of nuclear matter.

    nucl-thNPA(2020)·2 citations
  4. 04

    Exploring continuum structures in reactions with three-body nuclei

    J. Casal🇮🇹 · M. Gómez-Ramos🇩🇪 · A. M. Moro🇪🇸 · A. Corsi🇫🇷

    The Transfer to the Continuum method has been applied to describe the and reactions in inverse kinematics, using structure overlaps computed within a full three-body model for the projectile. Calculations agree with the available experimental data on the unbound Li and Be nuclei.

    nucl-thnucl-exJ.Phys.Conf.Ser.(2020)·2 citations
  5. 05

    Implications of the fermion vacuum term in the extended SU(3) Quark Meson model on compact stars properties

    Andreas Zacchi🇩🇪 · Juergen Schaffner-Bielich🇩🇪

    We study the impact of the fermion vacuum term in the SU(3) quark meson model on the equation of state and determine the vacuum parameters for various sigma meson masses. We examine its influence on the equation of state and on the resulting mass radius relations for compact stars. The tidal deformability of the stars is studied and compared to the results of the mean field approximation. Parameter sets which fulfill the tidal deformability bounds of GW170817 together with the observed two solar mass limit turn out to be restricted to a quite small parameter range in the mean field approximation. The extended version of the model does not yield solutions fulfilling both constraints. Furthermore, no first order chiral phase transition is found in the extended version of the model, not allowing for the twin star solutions found in the mean field approximation.

    nucl-thastro-ph.HEhep-phPRD(2019)·21 citations
  6. 06

    -delayed proton emission from Be in effective field theory

    Wael Elkamhawy🇩🇪 · Zichao Yang🇺🇸 · Hans-Werner Hammer🇩🇪 · Lucas Platter🇺🇸

    We calculate the rate of the rare decay into using Halo effective field theory, thereby describing the process of beta-delayed proton emission. We assume a shallow resonance in the system with an energy consistent with a recent experiment by Ayyad et al. and obtain for the branching ratio of this decay, predicting a resonance width of . Our calculation shows that the experimental branching ratio and resonance parameters of Ayyad et al. are consistent with each other. Moreover, we analyze the general impact of a resonance on the branching ratio and demonstrate that a wide range of combinations of resonance energies and widths can reproduce branching ratios of the correct order. Thus, no exotic mechanism (such as beyond the standard model physics) is needed to explain the experimental decay rate.

    nucl-thnucl-exPLB(2021)·18 citations
  7. 07

    Catching a glimpse of the parton structure of the bound proton

    Sara Fucini🇮🇹 · Sergio Scopetta🇮🇹 · Michele Viviani🇮🇹

    A new generation of experiments is expected to shed light on the elusive parton structure of the bound proton. One of the most promising directions is incoherent deeply virtual Compton scattering, which can provide a tomographic view of the bound proton. The first measurement has been recently performed, using He targets at Jefferson Lab. In the work presented here, a rigorous Impulse Approximation analysis of this process is proposed. As ingredients, state-of-the-art models of the nuclear spectral function and of the parton structure of the struck proton, together with novel scattering amplitudes expressions for a bound moving nucleon, have been used. A good overall agreement with the data is obtained, in particular at high values of the photon virtuality. The observed big difference between results for the bound proton and those for the free one turns out to be due in small part to modifications of the parton structure, and rather it should be related to kinematical nuclear effects. The analysis demonstrates that the comparison of the results of this approach, based on a conventional description, with future precise data, has the potential to expose exotic quark and gluon effects in nuclei.

    nucl-thhep-phnucl-exPRD(2020)·12 citations
  8. 08

    Probing the evolution of heavy-ion collisions using direct photon interferometry

    Oscar Garcia-Montero🇩🇪 · Nicole Löher🇩🇪 · Aleksas Mazeliauskas🇩🇪 · Jürgen Berges🇩🇪 · Klaus Reygers🇩🇪

    We investigate the measurement of Hanbury Brown-Twiss (HBT) photon correlations as an experimental tool to discriminate different sources of photon enhancement, which are proposed to simultaneously reproduce the direct photon yield and the azimuthal anisotropy measured in nuclear collisions at RHIC and the LHC. To showcase this, we consider two different scenarios in which we enhance the yields from standard hydrodynamical simulations. In the first, additional photons are produced from the early pre-equilibrium stage computed from the \textit{bottom-up} thermalization scenario. In the second, the thermal rates are enhanced close to the pseudo-critical temperature using a phenomenological ansatz. We compute the correlators for relative momenta and for different transverse pair momenta, , and find that the longitudinal correlation is the most sensitive to different photon sources. Our results also demonstrate that including anisotropic pre-equilibrium rates enhances non-Gaussianities in the correlators, which can be quantified using the kurtosis of the correlators. Finally, we study the feasibility of measuring a direct photon HBT signal in the upcoming high-luminosity LHC runs. Considering only statistical uncertainties, we find that with the projected heavy ion events a measurement of the HBT correlations for is statistically significant.

    hep-phnucl-exnucl-thPRC(2020)·24 citations
  9. 09

    Non-equilibrium photons from the bottom-up thermalization scenario

    Oscar Garcia-Montero🇩🇪

    In this work, I calculate the resolved spectra for the three stages of the \textit{bottom-up} scenario, which are comparable to the thermal contribution, particularly at higher values of the saturation scale . Analytical solutions are obtained by including a parametrization of scaling solutions from far-from-equilibrium classical statistical lattice simulations into a small angle kinetic rate. Furthermore, a theoretically motivated ansatz is used to account for near-collinear enhancement of the low- radiation. The system is phenomenologically constrained using the charge hadron multiplicities from LHC and RHIC as in previous parametric estimates and fair agreement with the data available for photons was found. I find that for this realistic set of parameters, the contribution from the thermalizing glasma dominates the excess photons.

    hep-phnucl-exnucl-thAnnals Phys.(2022)·21 citations

Affiliations

first authorsco-authorsvia INSPIRE