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Nuclear Theory·nucl-th

Thursday·March 31, 2022

8 papers—3 primary·5 cross-listed

All8Primary3Cross-lists5
  1. 01

    [Submitted on 29 Mar 2022]

    Ab initio prediction of the big bang radiative capture

    Chloë Hebborn🇺🇸 · Guillaume Hupin🇫🇷 · Konstantinos Kravvaris🇺🇸 · Sofia Quaglioni🇺🇸 · Petr Navrátil🇨🇦 · Peter Gysbers🇨🇦

    The rate at which helium (He) and deuterium () fuse together to produce lithium-6 (Li) and a ray, HeLi, is a critical puzzle piece in resolving the roughly three orders of magnitude discrepancy between big bang predictions and astronomical observations for the primordial abundance of Li. The accurate determination of this radiative capture rate requires the quantitative and predictive description of the fusion probability across the big bang energy window ( keV keV), where measurements are hindered by low counting rates. We present first-principles (or, ab initio) predictions of the HeLi astrophysical S-factor using validated nucleon-nucleon and three-nucleon interactions derived within the framework of chiral effective field theory. By employing the ab initio no-core shell model with continuum to describe - scattering dynamics and bound product on an equal footing, we accurately and consistently determine the contributions of the main electromagnetic transitions driving the radiative capture process. Our results reveal an enhancement of the capture probability below 100 keV owing to previously neglected magnetic dipole (M1) transitions and reduce by an average factor of 7 the uncertainty of the thermonuclear capture rate between and GK.

    Comments:
    5 pages, 2 figures and 6 pages supplemental material
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2203.15914 [pdf]
    PRL(2022)·36 citations
  2. 02

    [Submitted on 30 Mar 2022]

    Quantum Monte Carlo in Configuration Space with Three-Nucleon Forces

    Pierre Arthuis · Carlo Barbieri · Francesco Pederiva · Alessandro Roggero

    Neutron matter, through its connection to neutron stars as well as systems like cold atom gases, is one of the most interesting yet computationally accessible systems in nuclear physics. The Configuration-Interaction Monte Carlo (CIMC) method is a stochastic many-body technique allowing to tackle strongly coupled systems. In contrast to other Quantum Monte Carlo methods employed in nuclear physics, the CIMC method can be formulated directly in momentum space allowing for an efficient use of non-local interactions. In this work we extend CIMC method to include three-nucleon interactions through the normal-ordered two-body approximation. We present results for the equation of state of neutron matter in line with other many-body calculations that employ low resolution chiral interactions, and provide predictions for the momentum distribution and the static structure factor.

    Comments:
    9 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2203.16167 [pdf]
    PRC(2023)·18 citations
  3. 03

    [Submitted on 30 Mar 2022]

    Geometrical Scaling of Direct Photons in Relativistic Heavy Ion and d+Au Collisions

    Vladimir Khachatryan🇺🇸 · Michal Praszalowicz🇵🇱

    In this paper, we show that multiplicity spectra of direct photons in A+A and d+Au collisions at different centrality classes and different energies exhibit geometrical scaling, {\em i.e.}, they depend on a specific combination of number of participants , collisions energy , and transverse momentum -- called saturation scale -- rather than on all these three variables separately. In particular, the dependence on the geometry of collisions encoded in the dependence on is in agreement with the expectations based on the Color Glass Condensate theory.

    Comments:
    9 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2203.16204 [pdf]
    NPA(2023)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE