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Nuclear Theory·nucl-th

Tuesday·March 9, 2021

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 06

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

    Distribution amplitudes of light diquarks

    Ya Lu🇨🇳 · Daniele Binosi🇮🇹 · Minghui Ding🇮🇹 · Craig D. Roberts🇨🇳 · Hui-Yu Xing🇨🇳 · Chang Xu🇨🇳

    Accumulating evidence indicates that soft quark+quark (diquark) correlations play an important role in the structure and interactions of hadrons constituted from three or more valence-quarks; so, it is worth developing insights into diquark structure. Using a leading-order truncation of those equations needed to solve continuum two-valence-body bound-state problems, the leading-twist two-parton distribution amplitudes (DAs) of light-quark scalar and pseudovector diquarks are calculated. The diquark DAs are narrower and taller than the asymptotic profile that characterises mesons. Consequently, the valence quasiparticles in a diquark are less likely to carry a large light-front fraction of the system's total momentum than those in a meson. These features may both influence the form of baryon DAs and be transmitted to diquark distribution functions (DFs), in which case their impact will be felt, e.g. in the proton's and valence-quark DFs.

    Comments:
    8 pages, 2 figures, 1 table. Accepted for publication in Eur. Phys. J. A (Lett)
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2103.03960 [pdf]
    EPJA(2021)·16 citations
  2. 07

    [Submitted on 7 Mar 2021] (cross-list from gr-qc)

    Neutron interferometry and tests of short-range modifications of gravity

    J. M. Rocha🇧🇷 · F. Dahia🇧🇷

    We consider tests of short-distance modifications of gravity based on neutron interferometry in the scenario of large extra dimensions. Avoiding the non-computability problem in the calculation of the internal gravitational potential of extended sources, typical of models with zero-width brane, we determine the neutron optical potential associated with the higher-dimension gravitational interaction between the incident neutron and a material medium in the context of thick brane theories. Proceeding this way, we identify the physical quantity of the extra dimension model that the neutron interferometry is capable of constraining. We also consider interferometric experiments in which the phase shifter is an electric field, as in the test of the Aharanov-Casher effect. We argue that this experiment, with this non-baryonic source, can be viewed as a test of the short-range behavior of Post-Newtonian parameters that measure the capacity of the pressure and the internal energy for producing gravity.

    Subjects:
    General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2103.04218 [pdf]
    PRD(2021)·11 citations
  3. 08

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

    On the light front surfaces in the phase space of hadrons in heavy-ion collisions

    Rahul Ramachandran Nair🇵🇱

    Surfaces corresponding to the constant values of the light front variable forms paraboloids in the phase space of the inclusively produced hadrons in heavy-ion collisions. In this paper, it is demonstrated with the simulated Au-Au collisions at GeV using the UrQMD event generator that the paraboloidal surface defined by a certain constant value of the light front variable divides the particles in the phase space into two groups such that the distributions of the square of the transverse momentum, the polar angle and the light front variable of particles belonging to one among them can be described with the Boltzmann distribution parameterised by the mass-dependent temperature.

    Comments:
    6 pages, 4 figures, 1 table
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2103.04299 [pdf]
    1 citation
  4. 09

    [Submitted on 8 Mar 2021] (cross-list from hep-ph)

    Improved radiative corrections sharpen the -- discrepancy

    Chien-Yeah Seng🇩🇪 · Daniel Galviz🇩🇪 · Mikhail Gorchtein🇩🇪 · Ulf-G. Meißner🇩🇪

    The measurements of in leptonic and semileptonic kaon decays exhibit a disagreement, which could originate either from physics beyond the Standard Model or some large unidentified Standard Model systematic effects. Clarifying this issue requires a careful examination of all existing Standard Model inputs. Making use of a newly-proposed computational framework and the most recent lattice QCD results, we perform a comprehensive re-analysis of the electroweak radiative corrections to the decay rates that achieves an unprecedented level of precision of , which improves the current best results by almost an order of magnitude. No large systematic effects are found, which suggests that the electroweak radiative corrections should be removed from the ``list of culprits'' responsible for the -- discrepancy.

    Comments:
    Version accepted by JHEP
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2103.04843 [pdf]
    JHEP(2021)·40 citations

Affiliations

first authorsco-authorsvia INSPIRE