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Nuclear Theory·nucl-th

Monday·March 26, 2018

11 papers—4 primary·7 cross-listed

All11Primary4Cross-lists7
  1. 05

    [Submitted on 22 Mar 2018] (cross-list from hep-ph)

    Particle physics origin of the 5 MeV bump in the reactor antineutrino spectrum?

    Jeffrey M. Berryman🇺🇸 · Vedran Brdar🇩🇪 · Patrick Huber🇺🇸

    One of the most puzzling questions in neutrino physics is the origin of the excess at 5 MeV in the reactor antineutrino spectrum. In this paper, we explore the excess via the reaction CC in organic scintillator detectors. The de-excitation of C yields a prompt MeV photon, while the thermalization of the product neutron causes proton recoils, which in turn yield an additional prompt energy contribution with finite width. Together, these effects can mimic an inverse beta decay event with around 5 MeV energy. We consider several non-standard neutrino interactions to produce such a process and find that the parameter space preferred by Daya Bay is disfavored by measurements of neutrino-induced deuteron disintegration and coherent elastic neutrino-nucleus scattering. While non-minimal particle physics scenarios may be viable, a nuclear physics solution to this anomaly appears more appealing.

    Comments:
    13 pages, 5 figures, matches published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1803.08506 [pdf]
    PRD(2019)·39 citations
  2. 06

    [Submitted on 22 Mar 2018] (cross-list from hep-ph)

    Chiral and restoration for the scalar/pseudoscalar meson nonets

    A. Gómez Nicola🇪🇸 · J. Ruiz de Elvira🇨🇭

    We analyze the restoration pattern of the members of the scalar and pseudoscalar meson nonets under chiral and symmetries. For that purpose, we exploit QCD Ward Identities (WI), which allow one to relate susceptibilities with quark condensates, as well as susceptibility differences with meson vertices. In addition, we consider the low-energy realization of QCD provided by Chiral Perturbation Theory (ChPT) at finite temperature to perform a full analysis of the different correlators involved. Our analysis suggests partner restoration if chiral symmetry partners are also degenerated. This is also confirmed by the ChPT analysis when the light chiral limit is reached. Partner degeneration for the sector, the behavior of mixing and the temperature scaling of meson masses predicted by WI are also studied. Special attention is paid to the connection of our results with recent lattice analyses.

    Comments:
    28 pages and 16 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1803.08517 [pdf]
    PRD(2018)·38 citations
  3. 07

    [Submitted on 23 Mar 2018] (cross-list from hep-ph)

    Regge Trajectories of Radial Meson Excitations: Exploring the Dyson-Schwinger-- Bethe-Salpeter Approach

    R. Greifenhagen🇩🇪 · B. Kämpfer🇩🇪 · L. P. Kaptari🇩🇪

    The combined Dyson-Schwinger and Bethe-Salpeter equations in rainbow-ladder approximation are used to search for Regge trajectories of mesons in the pseudo-scalar and vector channels. We focus on the often employed Alkofer-Watson-Weigel kernel which is known to deliver good results for the ground state meson spectra; it provides linear Regge trajectories in the channel.

    Comments:
    12 pages, 6 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1803.08676 [pdf]
    Springer book, FIAS Interdisciplinary Sci…·2 citations
  4. 08

    [Submitted on 23 Mar 2018] (cross-list from hep-ph)

    Width of a two-body coupled-channel resonance

    H. Garcilazo🇲🇽 · A. Valcarce🇪🇸

    We study the width of a two-body resonance in a coupled-channel system. We demonstrate how the width does not come only determined by the available phase space for its decay to the detection channel, but it greatly depends on the relative position of the mass of the resonance with respect to the masses of the coupled-channels generating the state. Our results are consistent with the experimental observation of narrow hadrons lying well above their lowest decay threshold.

    Comments:
    10 pages, 3 figures. To appear in Eur. Phys. J. C
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1803.08685 [pdf]
    EPJC(2018)·12 citations
  5. 09

    [Submitted on 23 Mar 2018] (cross-list from hep-ph)

    Low lying eigenmodes and meson propagator symmetries

    C. B. Lang🇦🇹

    In situations where the low lying eigenmodes of the Dirac operator are suppressed one observed degeneracies of some meson masses. Based on these results a hidden symmetry was conjectured, which is not a symmetry of the Lagrangian but emerges in the quantization process. We show here how the difference between classes of meson propagators is governed by the low modes and shrinks when they disappear.

    Comments:
    9 pages, 3 figures; final version, accepted at Phys.Rev.D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1803.08693 [pdf]
    PRD(2018)·10 citations
  6. 10

    [Submitted on 23 Mar 2018] (cross-list from hep-ph)

    New physics searches in nuclear and neutron decay

    Martin Gonzalez-Alonso🇨🇭 · Oscar Naviliat-Cuncic🇺🇸 · Nathal Severijns🇧🇪

    The status of tests of the standard electroweak model and of searches for new physics in allowed nuclear decay and neutron decay is reviewed including both theoretical and experimental developments. The sensitivity and complementarity of recent and ongoing experiments are discussed with emphasis on their potential to look for new physics. Measurements are interpreted using a model-independent effective field theory approach enabling to recast the outcome of the analysis in many specific new physics models. Special attention is given to the connection that this approach establishes with high-energy physics. A new global fit of available -decay data is performed incorporating, for the first time in a consistent way, superallowed transitions, neutron decay and nuclear decays. The constraints on exotic scalar and tensor couplings involving left- or right-handed neutrinos are determined while a constraint on the pseudoscalar coupling from neutron decay data is obtained for the first time as well. The values of the vector and axial-vector couplings, which are associated within the standard model to and respectively, are also updated. The ratio between the axial and vector couplings obtained from the fit under standard model assumptions is . The relevance of the various experimental inputs and error sources is critically discussed and the impact of ongoing measurements is studied. The complementarity of the obtained bounds with other low- and high-energy probes is presented including ongoing searches at the Large Hadron Collider.

    Comments:
    70 pages, 14 figures. Invited review article for Prog. Part. Nucl. Phys. v2: Journal version (clarifications, references, and 2 new figures added)
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1803.08732 [pdf]
    PPNP(2019)·295 citations
  7. 11

    [Submitted on 23 Mar 2018] (cross-list from hep-ph)

    Renormalizing the zero point energy in dense QCD

    Toru Kojo🇨🇳

    We analyze the zero point energy in a dense matter of quarks or hadrons with particular attention on the renormalization of the UV divergences. Besides divergences removable by the vacuum subtraction and counter terms, there are also UV divergences associated with non-perturbative modifications of quark bases appearing in the in-medium propagators. The latter would remain after the self-energies and vertices are renormalized, unless a proper set of medium contributions is included at a given truncation. We use the formalism of the two particle irreducible action to clarify how the UV divergences are assembled to cancel. An example is given for the thermodynamic potentials with mesons as composite particles whose zero point energies apparently diverge but can be cancelled by the quark self-energy contributions. Important applications of this work are quark matter with hadronic correlations which may be realized at the core of neutron stars.

    Comments:
    v2: 12 pages, 4 figures, discussions of renormalizability were revised
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1803.08796 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE