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Nuclear Theory·nucl-th

Wednesday·March 31, 2021

9 papers—6 primary·3 cross-listed

All9Primary6Cross-lists3
  1. 07

    [Submitted on 29 Mar 2021] (cross-list from hep-ph)

    The role of symmetry breaking in the QCD corrections to the pion mass difference

    Mahammad Sabir Ali🇮🇳 · Chowdhury Aminul Islam🇨🇳 · Rishi Sharma🇮🇳

    The charged and neutral pion mass difference can be attributed to both the QED and QCD contributions. The current quark mass difference () is the source of the QCD contribution. Here, in a two-flavour non-local NJL model, we try to estimate the QCD contribution. Interestingly, we find that the strength of the symmetry-breaking parameter plays a crucial role in obtaining the pion mass difference while intertwined with the current quark mass difference. To obtain the QCD contribution for the pion mass difference, we scan the parameter space in , and by comparing this with the existing results, we constrained the parameter space. Further, using a fitted value of , we determine the allowed range for the in the model. The model estimated ranges enable us to extract the chiral perturbation theory low-energy constant, and verify the dependence of the pion mass difference on . We also find out its dependence on \textemdash\, it increases with the decreasing value of , i.e., toward an axial anomaly restored phase.

    Comments:
    12 pages, 6 captioned figures, discussion on l7 has been added, accepted in JPG
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2103.15849 [pdf]
    J.Phys.G(2023)·7 citations
  2. 08

    [Submitted on 29 Mar 2021] (cross-list from hep-ph)

    Constraining the strength of symmetry breaking using 2-flavour non-local NJL model

    Mahammad Sabir Ali🇮🇳 · Chowdhury Aminul Islam🇨🇳 · Rishi Sharma🇮🇳

    In presence of magnetic field we have done a systematic analysis to constrain the strength of 't Hooft determinant term using LQCD data within a non-local version of two flavour NJL model. Topological susceptibility, being related to the axial symmetry, have also been calculated and compared with LQCD results to further validate our calculation.

    Comments:
    Proceedings of the contributory talk at XXIV DAE-BNRS High Energy Physics Symposium 2020 held at NISER, Bhubaneswar, Odisha
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2103.15883 [pdf]
    Springer Proc.Phys.(2022)·1 citation
  3. 09

    [Submitted on 29 Mar 2021] (cross-list from hep-ph)

    Heavy+light pseudoscalar meson semileptonic transitions

    Zhen-Ni Xu🇨🇳 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳 · Chang Xu🇨🇳

    A symmetry-preserving regularisation of a vectorvector contact interaction (SCI) is used to deliver a unified treatment of semileptonic transitions involving , , , initial states. The framework is characterised by algebraic simplicity, few parameters, and the ability to simultaneously treat systems from Nambu-Goldstone modes to heavy+heavy mesons. Although the SCI form factors are typically somewhat stiff, the results are comparable with experiment and rigorous theory results. Hence, predictions for the five unmeasured branching fractions should be a reasonable guide. The analysis provides insights into the effects of Higgs boson couplings via current-quark masses on the transition form factors; and results on transitions yield a prediction for the Isgur-Wise function in fair agreement with contemporary data.

    Comments:
    17 pages, 13 figures, 3 tables
    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:
    2103.15964 [pdf]
    EPJC(2021)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE