Nuclear Theory·nucl-th

Monday·February 27, 2023

6 papers—2 primary·4 cross-listed

03
Universality (beyond leading log) of soft radiative corrections to $q^$ in $p_{⊥}$ broadening and energy loss
Peter Arnold🇺🇸
It has been known for many years that soft radiation can give potentially large double-logarithm corrections to $p_{⊥}$ broadening of a high-energy particle traveling through QCD matter, but that this soft radiation correction can be absorbed into an effective value $q^_{eff}$ for the medium $p_{⊥}$ -broadening parameter $q^$ . Here "soft" means high energy compared to medium scales but soft compared to the original high-energy particle traveling through the medium. A similar situation arises in the case of soft corrections to hard splitting of a high-energy particle, such as hard $g \to g g$ , where double logarithms can also be absorbed using the same effective $q^_{eff}$ . In this paper, I study whether the same holds true for potentially large, subleading, *single*-logarthim corrections. The correspondence is more indirect for single logarithms, but I show (in the large- $N_{c}$ limit) that single logarithms from soft radiation in the case of $p_{⊥}$ broadening also determine the single logarithms from soft radiative corrections to hard $g \to g g$ splitting. Along the way, there is an interesting variation of the original BDMPS-Z calculation of splitting rates in the $q^$ approximation. I also discuss how, for soft-radiative corrections to hard splitting processes, there are two different types of " $q^_{eff}$ " that come into play, which differ by " $iπ$ " terms that multiply single logarithms.
↳ hep-phnucl-thJHEP(2022)·18 citations
04
Dispersion relations for hadronic light-by-light scattering in triangle kinematics
Jan Lüdtke🇦🇹 · Massimiliano Procura🇦🇹 · Peter Stoffer🇨🇭
We present a new strategy for the dispersive evaluation of the hadronic light-by-light contribution to the anomalous magnetic moment of the muon $a_{μ}$ . The new approach directly applies in the kinematic limit relevant for $a_{μ}$ : one of the photons is treated as an external electromagnetic field with vanishing momentum, so that the kinematics corresponds to a triangle. We derive expressions for the relevant single-particle intermediate states, as well as the tensor decompositions of the two-pion sub-processes that appear in addition to those needed in the established dispersive approach. The existing approach is based on a set of dispersion relations for the hadronic light-by-light tensor in four-point kinematics. At present it is not known how to consistently include in this framework resonant intermediate states of spin 2 or larger, due to the appearance of kinematic singularities that can be traced back to the redundancy of the tensor decomposition. We show that our new approach circumvents this problem and enables dispersion relations in the limit of triangle kinematics that are manifestly free from kinematic singularities, paving the way towards a data-driven evaluation of all relevant exclusive hadronic intermediate states.
↳ hep-phhep-exhep-latnucl-thJHEP(2023)·38 citations
05
In-medium properties of the light and heavy-light mesons in a light-front quark model
Ahmad Jafar Arifi🇰🇷 · Parada. T. P. Hutauruk🇰🇷 · Kazuo Tsushima🇧🇷
We investigate the in-medium properties of pseudoscalar and vector mesons with the light-light and heavy-light quarks in a light-front quark model, using the in-medium quark properties computed by the quark-meson coupling model. Both models are constructed on an equal footing with the constituent quark degree of freedom. Here, we particularly focus on the weak decay constants and distribution amplitudes (DAs) of the mesons in symmetric nuclear matter. We find that the weak decay constants decrease as nuclear density increases for $π$ , $K$ , $D$ , and $B$ pseudoscalar as well as $ρ$ , $K^{*}$ , $D^{*}$ , and $B^{*}$ vector mesons, where their properties in free space have good agreement with the available experimental and lattice QCD data. A larger reduction is found for the light-light quark pseudoscalar mesons, while a smaller reduction is found for the heavy-light quark vector mesons, in particular, with the bottom quark. We discuss the effect of the vector potential on the weak decay constants and present our predictions for the in-medium modifications of DAs. Also, a comparison with the free space lattice QCD data is made.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·22 citations
06
Medium Correction to Gravitational Form Factors
Shu Lin🇨🇳 · Jiayuan Tian
We generalize the gravitational form factor for chiral fermion in vacuum, which reproduces the well-known spin-vorticity coupling. We also calculate radiative correction to the gravitational form factors in quantum electrodynamics plasma. We find two structures in the form factors contributing to the scattering amplitude of fermion in vorticity field, one is from the fermion self-energy correction, pointing to suppression of spin-vorticity coupling in medium; the other structure comes from graviton-fermion vertex correction, which does not adopt potential interpretation, but corresponds to transition matrix element between initial and final states. Both structures contribute to axial chiral vortical effect. The net effect is that radiative correction enhances the axial chiral vortical effect. Our results clarify the relation and difference between spin-vorticity coupling and axial chiral vortical effect from the perspective of form factors. We also discuss the application of the results in quantum chromodynamic plasma, indicating radiative correction might have an appreciable effect in spin polarization effect in heavy ion collisions.
↳ hep-phnucl-thActa Phys.Sin.(2023)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Universality (beyond leading log) of soft radiative corrections to q^​ in p⊥​ broadening and energy loss

Dispersion relations for hadronic light-by-light scattering in triangle kinematics

In-medium properties of the light and heavy-light mesons in a light-front quark model

Medium Correction to Gravitational Form Factors

Affiliations

Universality (beyond leading log) of soft radiative corrections to $q^$ in $p_{⊥}$ broadening and energy loss