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Nuclear Theory·nucl-th

Thursday·September 17, 2020

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 01

    Imprint of nuclear bubble in nucleon-nucleus diffraction

    V. Choudhary · W. Horiuchi · M. Kimura · R. Chatterjee

    Background: The density of most nuclei is constant in the central region and is smoothly decreasing at the surface. A depletion in the central part of the nuclear density can have nuclear structure effects leading to the formation of "bubble" nuclei. However, probing the density profile of the nuclear interior is, in general, very challenging. Purpose: The aim of this paper is to investigate the nuclear bubble structure, with nucleon-nucleus scattering, and quantify the effect that has on the nuclear surface profile. Method: We employed high-energy nucleon-nucleus scattering under the aegis of the Glauber model to analyze various reaction observables, which helps in quantifying the nuclear bubble. The effectiveness of this method is tested on Si with harmonic-oscillator (HO) densities, before applying it on even-even isotones, in the mass range, with realistic densities obtained from antisymmetrized molecular dynamics (AMD). Results: Elastic scattering differential cross sections and reaction probability for the proton-Si reaction are calculated using the HO density to design tests for signatures of nuclear bubble structure. We then quantify the degree of bubble structure for isotones with the AMD densities by analyzing their elastic scattering at 325, 550 and 800 MeV incident energies. The present analyses suggest O as a candidate for a bubble nucleus, among even-even isotones, in the mass range. Conclusion: We have shown that the bubble structure information is imprinted on the nucleon-nucleus elastic scattering differential cross section, especially in the first diffraction peak. Bubble nuclei tend to have a sharper nuclear surface and deformation seems to be a hindrance in their emergence.

    nucl-thnucl-exPRC(2020)·25 citations
  2. 02

    Event-plane decorrelation of photons produced in the early stage of heavy-ion collisions

    Charles Gale · Jean-François Paquet · Björn Schenke · Chun Shen

    We study photon production in the early stage of heavy-ion collisions using a multistage model combining IP-Glasma, Kø{}MPø{}ST and relativistic hydrodynamics. We discuss the small momentum anisotropy of these photons, highlighting the role of the photon-hadron event-plane decorrelation. We comment that this singular characteristic of early photons could be used to provide dynamical information on the complex pre-hydrodynamics phase of heavy-ion collisions.

    nucl-thPoS(2021)·4 citations
  3. 03

    Prior probability distributions of neutron star crust models

    Lauren Balliet · William Newton · Sarah Cantu · Srdan Budimir

    To make best use of multi-faceted astronomical and nuclear data-sets, probability distributions of neutron star models that can be used to propagate errors consistently from one domain to another are required. We take steps toward a consistent model for this purpose, highlight where model inconsistencies occur and assess the resulting model uncertainty. Using two distributions of nuclear symmetry energy parameters - one uniform, the other based on pure neutron matter theory, we prepare two ensembles of neutron star inner crust models. We use an extended Skyrme energy-density functional within a compressible liquid drop model (CLDM). We fit the surface parameters of the CLDM to quantum 3D Hartree-Fock calculations of crustal nuclei. All models predict more than 50% of the crust by mass and 15% of the crust by thickness comprises pasta with medians of around 62% and 30% respectively. We also present 68% and 95% ranges for the crust composition as a function of density. We examine the relationships between crust-core boundary and pasta transition properties, the thickness of the pasta layers, the symmetry energy at saturation and sub-saturation densities and the neutron skins of 208Pb and 48Ca. We quantify the correlations using the maximal information coefficient, which can effectively characterize non-linear relationships. Future measurements of neutron skins, information from nuclear masses and giant resonances, and theoretical constraints on PNM will be able to place constraints on the location of the pasta and crust-core boundaries and the amount of pasta in the crust.

    ↳ astro-ph.HEnucl-thApJ(2021)·31 citations
  4. 04

    Coupled-channel interpretation of the LHCb double- spectrum and hints of a new state near the threshold

    Xiang-Kun Dong🇨🇳 · Vadim Baru🇩🇪 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Alexey Nefediev🇷🇺

    Recently, the LHCb Collaboration reported pronounced structures in the invariant mass spectrum of -pairs produced in proton-proton collisions at the Large Hadron Collider. In this Letter, we argue that the data can be very well described within two variants of a coupled-channel approach employing -matrices consistent with unitarity: (i) with just two channels, and , as long as energy-dependent interactions in these channels are allowed, or (ii) with three channels , and with just constant contact interactions. Both formulations hint at the existence of a near-threshold state in the system with the quantum numbers or , which we refer to as . We suggest experimental tests to check the existence of this state and discuss what additional channels need to be studied experimentally to allow for distinctive tests between the two mechanisms proposed. If the molecular nature of the , as hinted by the three-channel approach, is confirmed, many other double-quarkonium states should exist driven by the same binding mechanism. In particular, there should be an molecule with a similar binding energy.

    ↳ hep-phhep-exhep-latnucl-thPRL(2021)·150 citations

Affiliations

first authorsco-authorsvia INSPIRE