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Nuclear Theory·nucl-th

Friday·February 21, 2020

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 01

    Assessment of the beta-delayed proton decay rate of Be

    Alexander Volya

    The Be neutron halo nucleus appears to decay into Be with a rate that exceeds expectations. Neutron disappearance into dark matter, beta decay of a halo neutron, or beta-delayed proton decay have been offered as explanations. In this work we study the latter option; we carry out shell model calculations and sequential decay analysis examining the beta-delayed proton decay going through a resonance in B. The narrow energy window, lack of states with sufficient spectroscopic strength, overwhelming alpha decay branch, all make reconciling the observed rate with beta-delayed proton decay difficult.

    nucl-thnucl-exEPL(2020)·16 citations
  2. 02

    Elliptic flow splitting between protons and antiprotons from hadronic potentials

    Pengcheng Li🇨🇳 · Yongjia Wang🇨🇳 · Jan Steinheimer🇩🇪 · Qingfeng Li🇨🇳 · Hongfei Zhang🇨🇳

    The difference in elliptic flow between protons and antiprotons, produced in collisions at center-of-mass energies , is studied within a modified version of the ultrarelativistic quantum molecular dynamics (UrQMD) model. Two different model scenarios are compared: the cascade mode and the mean field mode which includes potential interactions for both formed and pre-formed hadrons. The model results for the elliptic flow of protons and the relative difference between protons and antiprotons obtained from the mean field mode agree with the available experimental data, while the difference is near zero for the cascade mode. Our results show that the elliptic flow splitting, observed for particles and antiparticles, can be explained by the inclusion of proper hadronic interactions. In addition, the difference in between protons and antiprotons depends on the centrality and the rapidity window. With smaller centrality and/or rapidity acceptance, the observed elliptic flow splitting is more sensitive to the beam energy, indicating a strong net baryon density dependence of the effect. We propose to confirm this splitting at the upcoming experiments from Beam Energy Scan (BES) Phase-\Rmnum{2} at Relativistic Heavy Ion Collider (RHIC), the Compressed Baryonic Matter (CBM) at Facility for Antiproton and Ion Research (FAIR), High Intensity heavy ion Accelerator Facility (HIAF) and Nuclotron-based Ion Collider fAcility (NICA).

    nucl-thMod.Phys.Lett.A(2020)·8 citations
  3. 03

    Evidence for Tetrahedral Structure of Calcium-40

    N. S. Manton

    More than 100 excited states of the Calcium-40 nucleus, with isospin 0, are classified into rotational-vibrational bands of an intrinsic tetrahedral structure. Almost all observed states below 8 MeV can be accommodated, as well as many high-spin states above 8 MeV. The bands have some similarity to those classifying states of Oxygen-16, but the A-mode vibrational frequency is lower relative to the E-mode and F-mode frequencies than in Oxygen-16. Previously identified rotational bands up to spin 16 and energy above 20 MeV are unified here into a smaller number of tetrahedral bands.

    nucl-thIJMPE(2020)·6 citations
  4. 04

    Anisotropic transport properties of Hadron Resonance Gas in magnetic field

    Ashutosh Dash🇮🇳 · Subhasis Samanta🇵🇱 · Jayanta Dey🇮🇳 · Utsab Gangopadhyaya🇮🇳 · Sabyasachi Ghosh🇮🇳 · Victor Roy🇮🇳

    An intense transient magnetic field is produced in high energy heavy-ion collisions mostly due to the spectator protons inside the two colliding nucleus. The magnetic field introduces anisotropy in the medium and hence the isotropic scalar transport coefficients become anisotropic and split into multiple components. Here we calculate the anisotropic transport coefficients shear, bulk viscosity, electrical conductivity, and the thermal diffusion coefficients for a multicomponent Hadron- Resonance-Gas (HRG) model for a non-zero magnetic field by using the Boltzmann transport equation in a relaxation time approximation (RTA). The anisotropic transport coefficient component along the magnetic field remains unaffected by the magnetic field, while perpendicular dissipation is governed by the interplay of the collisional relaxation time and the magnetic time scale, which is inverse of the cyclotron frequency. We calculate the anisotropic transport coefficients as a function of temperature and magnetic field using the HRG model. The neutral hadrons are unaffected by the Lorentz force and do not contribute to the anisotropic transports, we estimate within the HRG model the relative contribution of isotropic and anisotropic transports as a function of magnetic field and temperature. We also give an estimation of these anisotropic transport coefficients for the hadronic gas at finite baryon chemical potential.

    nucl-thhep-phPRD(2020)·70 citations
  5. 05

    Correlation coefficient between harmonic and transverse flow in heavy-ion collisions

    Piotr Bozek🇵🇱 · Hadi Mehrabpour🇮🇷

    The correlation between the harmonic flow and the transverse flow in relativistic heavy ion collisions is calculated in the hydrodynamic model. The partial correlation coefficient, corrected for fluctuations of multiplicity, is compared to experimental data. Estimators of the final transverse and harmonic flow are used to predict the value of the correlation coefficient from the moments of the initial distribution. A good description of the hydrodynamic simulation results is obtained if the estimator for the final transverse flow, besides the most important transverse size and entropy, includes also the eccentricities.

    nucl-thnucl-exPRC(2020)·44 citations

Affiliations

first authorsco-authorsvia INSPIRE