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Nuclear Theory·nucl-th

Tuesday·June 8, 2021

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 06

    [Submitted on 4 Jun 2021] (cross-list from astro-ph.HE)

    Bayesian model-selection of neutron star equation of state using multi-messenger observations

    Bhaskar Biswas🇮🇳

    Measurement of macroscopic properties of neutron stars, whether in binary or in an isolated system, provides us a key opportunity to place a stringent constraint on its equation of state. In this paper, we perform Bayesian model-selection on a wide variety of neutron star equation of state using multi-messenger observations. In particular, (i) we use the mass and tidal deformability measurement from two binary neutron star merger event, GW170817 and GW190425; (ii) simultaneous mass-radius measurement of PSR J0030+0451 and PSR J0740+6620 by NICER collaboration, while the latter has been analyzed by joint NICER/radio/XMM-Newton collaboration. Among the 31 equations of state considered in this analysis, we are able to rule out different variants of MS1 family, SKI5, H4, and WFF1 EoSs decisively, which are either extremely stiff or soft equations of state. The most preferred equation of state model turns out to be AP3 (or MPA1), which predicts the radius and dimensionless tidal deformability of a neutron star to be 12.10 (12.50) km and 393 (513) respectively.

    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
    arXiv:
    2106.02644 [pdf]
    ApJ(2022)·66 citations
  2. 07

    [Submitted on 5 Jun 2021] (cross-list from hep-ph)

    Neutrino-Nucleus scattering in the SuSA model

    J.E. Amaro🇪🇸 · M.B. Barbaro🇮🇹 · J.A. Caballero🇪🇸 · T.W. Donnelly🇺🇸 · R. Gonzalez-Jimenez🇪🇸 · G.D. Megias🇪🇸 · I. Ruiz Simo🇪🇸

    The Super-Scaling Approach (SuSA) model, based on the analogies between electron and neutrino interactions with nuclei, is reviewed and its application to the description of neutrino-nucleus scattering is presented. The contribution of both one- and two-body relativistic currents is considered. A selection of results is presented where theoretical predictions are compared with cross section measurements from the main ongoing neutrino oscillation experiments.

    Comments:
    20 pages, 13 figures; submitted to EPJ-ST
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2106.02857 [pdf]
    Eur.Phys.J.ST(2021)·29 citations
  3. 08

    [Submitted on 7 Jun 2021] (cross-list from hep-ph)

    Classifying near-threshold enhancement using deep neural network

    Denny Lane B. Sombillo🇵🇭 · Yoichi Ikeda🇯🇵 · Toru Sato🇯🇵 · Atsushi Hosaka🇯🇵

    One of the main issues in hadron spectroscopy is to identify the origin of threshold or near-threshold enhancement. Prior to our study, there is no straightforward way of distinguishing even the lowest channel threshold-enhancement of the nucleon-nucleon system using only the cross-sections. The difficulty lies in the proximity of either a bound or virtual state pole to the threshold which creates an almost identical structure in the scattering region. Identifying the nature of the pole causing the enhancement falls under the general classification problem and supervised machine learning using a feed-forward neural network is known to excel in this task. In this study, we discuss the basic idea behind deep neural network and how it can be used to identify the nature of the pole causing the enhancement. The applicability of the trained network can be explored by using an exact separable potential model to generate a validation dataset. We find that within some acceptable range of the cut-off parameter, the neural network gives high accuracy of inference. The result also reveals the important role played by the background singularities in the training dataset. Finally, we apply the method to nucleon-nucleon scattering data and show that the network was able to give the correct nature of pole, i.e. virtual pole for partial cross-section and bound state pole for .

    Comments:
    10 pages, 4 figures, Contribution to the Proceedings for 8th Asia-Pacific Conference on Few-Body Problems in Physics (APFB2020), March 1-5 2021, Kanazawa, Japan
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2106.03453 [pdf]
    Few Body Syst.(2021)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE