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Nuclear Theory·nucl-th

Wednesday·September 29, 2021

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 07

    Meson-Baryon Couplings Revisited

    N. F. Nasrallah🇱🇧

    The theoretical evaluation of the coupling constants gpiNN , gKNLambda and gKNSigma is undertaken using QCD sum rules. These quantities were previously calculated with exponential (Borel) kernels used to suppress the unknown contributions of the hadronic continua. This method however introduces arbitrariness and instability in the calculation. In order to avoid these I redo the calculation using polynomial kernels tailored to vanish at the baryonic resonance masses. The results are gpiNN = 12.5 +- 1.0, gKNSigma = 5.45 +- .4, gKNSigma= -(12.7 - 15.0) which are close to experiment and to the predictions of SU(3) and which , with the corresponding Goldberger-Treiman Discrepancy satisfy quite well the Dashen-Weinstein relation.

    ↳ hep-phnucl-th0 citations
  2. 08

    Rotation and deformation of strangeon stars in the Lennard-Jones model

    Yong Gao🇨🇳 · Xiao-Yu Lai🇨🇳 · Lijing Shao🇨🇳 · Ren-Xin Xu🇨🇳

    The strong interactions at low energy scales determine the state of the supranuclear matter in the pulsar-like compact objects. It is proposed that the bulk strong matter could be composed of strangeons, which are quark clusters with a nearly equal number of three light-flavor quarks. In this work, to characterize the strong-repulsive interactions at short distances and the non-relativistic nature of the strangeons, the Lennard-Jones model is used to describe the equation of state (EoS) of strangeon stars (SSs). We investigate the static, the slowly rotating, and the tidally deformed SSs in detail. The corrections resulted from the finite surface densities are considered crucially in the perturbative approaches. We also study the universal relations between the moments of inertia, the tidal deformabilities, and the quadrupole moments. Those results are ready to be used for various purposes in astrophysics, and possible constraints from contemporary observations on the parameter space of the Lennard-Jones model are discussed. Future observations of the pulsars' radio signals, the X-ray emissions from the hot spots on the surface of the stars, and the gravitational waves (GWs) from binary mergers can give tighter constraints or even verify or falsify the existence of SSs.

    ↳ gr-qcastro-ph.HEhep-phnucl-thMNRAS(2021)·38 citations
  3. 09

    Consistent approach to study gluon quasi-particles

    Chowdhury Aminul Islam🇨🇳 · Munshi G. Mustafa🇮🇳 · Rajarshi Ray🇮🇳 · Pracheta Singha🇮🇳

    We discuss a novel approach to estimate the partition function in effective model frameworks when the effective potentials have multiple extrema, so that ascertaining a mean field becomes difficult. Using this approach we present a consistent model to study the thermodynamic properties of gluon quasi-particles as a function of temperature, both in the color confined and the color deconfined phases.

    ↳ hep-phhep-latnucl-thPRD(2022)·7 citations
  4. 10

    Critical Coupling for Two-dimensional Theory in Discretized Light-Cone Quantization

    James P. Vary🇺🇸 · Mengyao Huang🇺🇸 · Shreeram Jawadekar🇺🇸 · Mamoon Sharaf🇺🇸 · Avaroth Harindranath🇮🇳 · Dipankar Chakrabarti🇮🇳

    We solve for the critical coupling in the symmetric phase of two-dimensional field theory using Discretized Light-Cone Quantization. We adopt periodic boundary conditions, neglect the zero mode, and obtain a critical coupling consistent with the critical coupling reported using conformal truncation in light-front quantization. We find a 17% dfference from the critical coupling reported with light-front quantization in a symmetric polynomial basis.

    ↳ hep-thnucl-thPRD(2022)·12 citations
  5. 11

    Nuclear-Level Effective Theory of Conversion

    Evan Rule · W. C. Haxton · Ken McElvain

    The Mu2e and COMET conversion experiments are expected to significantly advance limits on new sources of charged lepton flavor violation (CLFV). Almost all theoretical work in the field has focused on just two operators. However, general symmetry arguments lead to a conversion rate with six response functions, each of which, in principle, is observable by varying nuclear properties of targets. We construct a nucleon-level nonrelativistic effective theory (NRET) to clarify the microscopic origin of these response functions and to relate rate measurements in different targets. This exercise identifies three operators and their small parameters that control the NRET operator expansion. We note inconsistencies in past treatments of these parameters. The NRET is technically challenging, involving 16 operators, several distorted electron partial waves, bound muon upper and lower components, and an exclusive nuclear matrix element. We introduce a trick for treating the electron Coulomb effects accurately, which enables us to include all of these effects while producing transition densities whose one-body matrix elements can be evaluated analytically, greatly simplifying the nuclear physics. We derive bounds on operator coefficients from existing and anticipated conversion experiments. We discuss how similar NRET formulations have impacted dark matter phenomenology, noting that the tools this community has developed could be adapted for CLFV studies.

    ↳ hep-phnucl-thPRL(2023)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE