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Nuclear Theory·nucl-th

Wednesday·July 17, 2019

7 papers—2 primary·5 cross-listed

All7Primary2Cross-lists5
  1. 03

    [Submitted on 13 Jul 2019] (cross-list from physics.ins-det)

    Study of radioactivity built-up and decay with singles time-stamped data

    Sangeeta Das · Arkajyoti De · Balaram Dey · Sathi Sharma · Anik Adhikari · S. S. Alam · Arkabrata Gupta · Y. Sapkota · Ananya Das · A. Saha · Dibyadyuti Pramanik · T. Bhattacharjee and 3 other authors

    Time-stamped data have been used to estimate the decay half-lives of radioactive 118mSb and 64,66,68Ga nuclei. These nuclei are populated through the reaction 4He (Elab = 32 MeV) + nat In and p (Elab = 10 MeV) + natZn, respectively. The g -rays emitted by the excited daughter nuclei are detected by a single high purity germanium (HPGe) detector and the data are acquired using a CAEN 5780M desktop digitizer. Half-lives of different orders of magnitudes for the above mentioned nuclei are obtained from both the decay of parent and the growth of daughter nuclei. It is observed that the half-lives obtained from both these techniques match fairly well and also are consistent with the reported values. It is demonstrated that the time-stamped data can be useful while studying certain half-lives which are too long for measurement using in-beam electronic technique and too short for decay studies in off-beam methods. The data also have a special relevance for constant monitoring of beam current and beam-tuning.

    Comments:
    13 Pages, 4 figures
    Subjects:
    Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1907.06631 [pdf]
    JINST(2019)·2 citations
  2. 04

    [Submitted on 15 Jul 2019] (cross-list from hep-ph)

    Radiative Corrections to Neutron and Nuclear Beta Decays Revisited

    Andrzej Czarnecki🇨🇦 · William J. Marciano🇺🇸 · Alberto Sirlin🇺🇸

    The universal radiative corrections common to neutron and super-allowed nuclear beta decays (also known as ``inner'' corrections) are revisited in light of a recent dispersion relation study that found , i.e.~about larger than the previous evaluation. For comparison, we consider several alternative computational methods. All employ an updated perturbative QCD four-loop Bjorken sum rule (BjSR) defined QCD coupling supplemented with a nucleon form factor based Born amplitude to estimate axial-vector induced hadronic contributions. In addition, we now include hadronic contributions from low loop effects based on duality considerations and vector meson resonance interpolators. Our primary result, corresponds to an average of a Light Front Holomorphic QCD approach and a three resonance interpolator fit. It reduces the dispersion relation discrepancy to approximately and thereby provides a consistency check. Consequences of our new radiative correction estimate, along with that of the dispersion relation result, for CKM unitarity are discussed. The neutron lifetime- connection is updated and shown to suggest a shorter neutron lifetime s. We also find an improved bound on exotic, non-Standard Model, neutron decays or oscillations of the type conjectured as solutions to the neutron lifetime problem, .

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1907.06737 [pdf]
    PRD(2019)·208 citations
  3. 05

    [Submitted on 16 Jul 2019] (cross-list from astro-ph.HE)

    Collision of ultra-relativistic proton with strong magnetic field: production of ultra-high energy photons and neutrinos

    Ye-Fei Yuan🇨🇳 · Xin-Yue Shi (USTC)🇨🇳

    Proton-proton interaction and photo-hadronic interaction in cosmic accelerators are the two main channels for the production of cosmic ultra-high energy photons and neutrinos (TeV-PeV). In this Letter, we use FWW approach to obtain the production of cosmic ultra-high energy photons and neutrinos from the collision between UHE proton with magnetic field which could be considered as the virtualphoton in the rest frame of UHE proton. We name this as process. The threshold for the occurrence of the process is that the combination of the Lorentz factor of proton and the strength of the magnetic field is about Gauss. Beyond this threshold, the rate of energy loss of proton due to the process is about three orders higher than that due to the synchrotron radiation of proton in the same magnetic field. The process might potentially happen in the atmosphere of white dwarfs, neutron stars or even that of stellar massive black holes.

    Comments:
    14 pages, 3 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1907.06807 [pdf]
    PLB(2019)·2 citations
  4. 06

    [Submitted on 16 Jul 2019] (cross-list from hep-ph)

    Pseudoscalar-Meson Contributions to g-2 via Schwinger's Sum Rule

    Franziska Hagelstein (AEC Bern)🇨🇭 · Vladimir Pascalutsa (JGU Mainz)🇩🇪

    The Schwinger sum rule is presented as a new promising tool to study the hadronic contributions to the muon anomalous magnetic moment. In particular, we show preliminary results for the light-by-light scattering contribution of pseudoscalar mesons.

    Comments:
    Contribution to the proceedings of the 9th International Workshop on Chiral Dynamics, 17-21 September 2018 (Durham, NC, USA). 7 pages, 7 figures, 2 tables
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1907.06927 [pdf]
    PoS(2019)·5 citations
  5. 07

    [Submitted on 16 Jul 2019] (cross-list from hep-ph)

    Revisiting model relations between T-odd transverse-momentum dependent parton distributions and generalized parton distributions

    B. Pasquini🇮🇹 · S. Rodini🇮🇹 · A. Bacchetta (Pavia U. & INFN, Pavia)🇮🇹

    We revisit the connection between generalized parton distributions in impact parameter space and T-odd effects in single spin asymmetries of the semi-inclusive deep inelastic process. We show that nontrivial relations can be established only under very specific conditions, typically realized only in models that describe hadrons as two-body bound systems and involving a helicity-conserving coupling between the gauge boson and the spectator system. Examples of these models are the the scalar-diquark spectator model or the quark-target model for the nucleon, and relativistic models for the pion at the lowest order in the Fock-space expansion.

    Comments:
    15 pages, 2 figures, 1 table, v2: list of references has been corrected
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1907.06960 [pdf]
    PRD(2019)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE