Nuclear Theory·nucl-th

Tuesday·February 16, 2021

12 papers—7 primary·5 cross-listed

08
[Submitted on 14 Feb 2021] (cross-list from hep-ph)
Heavy quark transport in an anisotropic hot QCD medium: Collisional and Radiative processes
Jai Prakash🇮🇳 · Manu Kurian🇮🇳 · Santosh K. Das🇮🇳 · Vinod Chandra🇮🇳
The impact of momentum anisotropy on the heavy quark transport coefficients due to collisional and radiative processes in the QCD medium has been studied within the ambit of kinetic theory. Anisotropic aspects (momentum) are incorporated into the heavy quark dynamics through the non-equilibrium momentum distribution function of quarks, antiquarks, and gluons. These non-equilibrium distribution functions that encode the physics of momentum anisotropy and turbulent chromo-fields have been obtained by solving the ensemble-averaged diffusive Vlasov-Boltzmann equation. The momentum dependence of heavy quark transport coefficients in the medium is seen to be sensitive to the strength of the anisotropy for both collisional and radiative processes. In addition, the collisional and radiative energy loss of the heavy quark in the anisotropic hot QCD medium have been analyzed. The effects of anisotropy on the drag and diffusion coefficients are observed to have a visible impact on the nuclear suppression factor both at the RHIC and LHC.
Comments:
11 pages, 4 figures, Version accepted for publication in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2102.07082 [pdf]
PRD(2021)·28 citations
09
[Submitted on 14 Feb 2021] (cross-list from hep-ph)
Thermal quarks and gluon propagators in two-color dense QCD
Toru Kojo🇨🇳 · Daiki Suenaga🇯🇵
We study Landau gauge gluon propagators in two-color QCD at finite quark chemical potential ( $μ_{q}$ ) and temperature ( $T$ ). We include medium polarization effects at one-loop by quarks into massive gluon propagators, and compared the analytic results with the available lattice data. We particularly focus on the high density phase of color-singlet diquark condensates whose critical temperature is $\sim 100$ MeV with weak dependence on $μ_{q}$ . At zero temperature the color singlet condensates protect the IR limit of electric and magnetic gluon propagators from the medium screening effects. At finite temperature, this behavior remains true for the magnetic sector, but the electric screening mass should be generated by thermal, and hence gapless, particles which are unbound from the diquark condensates. Treating thermal excitations as quasi-quarks, we found that the electric screening develops too fast compared to the lattice results. Beyond the critical temperature for diquark condensates the analytic results are consistent with the lattice results.
Comments:
10 pages, 10 figures; v2 published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2102.07231 [pdf]
PRD(2021)·24 citations
10
[Submitted on 15 Feb 2021] (cross-list from hep-ph)
Strong decays of the low-lying bottom strange baryons
Hui-Zhen He🇨🇳 · Wei Liang🇨🇳 · Qi-Fang Lü🇨🇳 · Yu-Bing Dong🇨🇳
In this work, the strong decay behaviors of the $λ -$ mode low-lying $Ξ_{b}$ and $Ξ_{b}^{'}$ baryons are investigated within the $^{3} P_{0}$ model. Our results suggest that all of the low-lying $3 ˉ_{F}$ states $Ξ_{b} (2 S)$ , $Ξ_{b} (1 P)$ , and $Ξ_{b} (1 D)$ have small decay widths of less than 20 MeV, and these states have good potentials to be observed in the $Ξ_{b}^{'} π$ and $Ξ_{b}^{' *} π$ invariant masses. Further, most of the $6_{F}$ multiplets are relatively narrow and may decay into the $Ξ_{b} π$ , $Ξ_{b}^{'} π$ , $Ξ_{b}^{' *} π$ , and $Λ_{b} K ˉ$ final states. Considering the masses and strong decay behaviors, we can assign the newly observed $Ξ_{b} (6100)$ resonance as the $Ξ_{b} (1 P)$ state with $J^{P} = 3/ 2^{-}$ and interpret the $Ξ_{b} (6227)$ structure as the $J^{P} = 3/ 2^{-}$ $Ξ_{b}^{'} (1 P)$ state with a proper mixing angle. We expect that our predictions for these excited bottom strange baryons will provide helpful information for future experimental research.
Comments:
7 pages, 3 figures. Minor modifications, accepted version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2102.07391 [pdf]
SCPMA(2021)·29 citations
11
[Submitted on 15 Feb 2021] (cross-list from hep-lat)
Isovector electromagnetic form factors of the nucleon from lattice QCD and the proton radius puzzle
D. Djukanovic🇩🇪 · T. Harris🇬🇧 · G. von Hippel🇩🇪 · P.M. Junnarkar🇩🇪 · H.B. Meyer🇩🇪 · D. Mohler🇩🇪 · K. Ottnad🇩🇪 · T. Schulz🇩🇪 · J. Wilhelm🇩🇪 · H. Wittig🇩🇪
We present results for the isovector electromagnetic form factors of the nucleon computed on the CLS ensembles with $N_{f} = 2 + 1$ flavors of $O (a)$ -improved Wilson fermions and an $O (a)$ -improved vector current. The analysis includes ensembles with four lattice spacings and pion masses ranging from 130 MeV up to 350 MeV and mainly targets the low- $Q^{2}$ region. In order to remove any bias from unsuppressed excited-state contributions, we investigate several source-sink separations between 1.0 fm and 1.5 fm and apply the summation method as well as explicit two-state fits. The chiral interpolation is performed by applying covariant chiral perturbation theory including vector mesons directly to our form factor data, thus avoiding an auxiliary parametrization of the $Q^{2}$ dependence. At the physical point, we obtain $μ = 4.71 (11)_{stat} (13)_{sys}$ for the nucleon isovector magnetic moment, in good agreement with the experimental value and $⟨ r_{M}^{2} ⟩ = 0.661 (30)_{stat} (11)_{sys} fm^{2}$ for the corresponding square-radius, again in good agreement with the value inferred from the $e p$ -scattering determination [Bernauer et~al., Phys. Rev. Lett., 105, 242001 (2010)] of the proton radius. Our estimate for the isovector electric charge radius, $⟨ r_{E}^{2} ⟩ = 0.800 (25)_{stat} (22)_{sys} fm^{2}$ , however, is in slight tension with the larger value inferred from the aforementioned $e p$ -scattering data, while being in agreement with the value derived from the 2018 CODATA average for the proton charge radius.
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2102.07460 [pdf]
PRD(2021)·50 citations
12
[Submitted on 15 Feb 2021] (cross-list from hep-ph)
Some Aspects of the Theory of Heavy Ion Collisions
Francois Gelis🇫🇷
We review the theoretical aspects relevant in the description of high energy heavy ion collisions, with an emphasis on the learnings about the underlying QCD phenomena that have emerged from these collisions.
Comments:
64 pages, invited review by Reports on Progress in Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2102.07604 [pdf]
Rept.Prog.Phys.(2021)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE

Heavy quark transport in an anisotropic hot QCD medium: Collisional and Radiative processes

Thermal quarks and gluon propagators in two-color dense QCD

Strong decays of the low-lying bottom strange baryons

Isovector electromagnetic form factors of the nucleon from lattice QCD and the proton radius puzzle

Some Aspects of the Theory of Heavy Ion Collisions

Affiliations