nucl-th digest · Mar 11, 2024

Scaling of pre-equilibrium dilepton production in QCD Kinetic Theory

We use QCD kinetic theory to compute dilepton production coming from the pre-equilibrium phase of the Quark-Gluon Plasma created in high-energy heavy-ion collisions. We demonstrate that the dilepton spectrum exhibits a simple scaling in terms of the specific shear viscosity

η / s

and entropy density

d S / d ζ \sim (T τ^{1/3})_{\infty}^{3/2}

, which can be derived from dimensional analysis in the presence of a pre-equilibrium attractor. Based on this scaling we perform event-by-event calculations of in-medium dilepton production and determine the invariant mass range where the pre-equilibrium yield is the leading contribution.

Comments:: 7 pages, 2 figures
Subjects:: High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:: 2403.04846 [pdf]

PRD(2025)·23 citations

[Submitted on 8 Mar 2024] (cross-list from hep-ph)

Phenomenological model for $γ γ^{} \to K K ˉ^{} (892)$ constraining the $f_{1} (1420)$ transition form factor

Xiu-Lei Ren🇩🇪 · Igor Danilkin🇩🇪 · Marc Vanderhaeghen🇩🇪

We present a phenomenological study of the $γ γ^{*} \to K K ˉ^{*} (892)$ process by including the $s$ -channel production of the $η (1475)$ and $f_{1} (1420)$ resonances. The non-resonant channel via $K$ - and $K^{*}$ -exchanges is investigated carefully by performing the Lorentz tensor decomposition and is constructed to yield a correct high-energy Regge behavior. The transition form factor of $f_{1} (1420)$ is adjusted to achieve a reasonable description of the existing L3 data in the $f_{1} (1420)$ resonance region. This model is intended to serve as a Monte Carlo generator for the analysis currently being performed by the BESIII Collaboration. We also estimate the polarized $γ γ^{*} \to K K ˉ^{*} (892)$ cross sections and demonstrate how to extract the transition form factors of $f_{1} (1420)$ from the polarized cross sections.

Comments:: 14 pages, 5 figures, 1 table; Introduction rewritten and discussion extended; version to appear in Phys. Rev. D
Subjects:: High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:: 2403.05091 [pdf]

PRD(2024)·1 citation

Monday·March 11, 2024

Scaling of pre-equilibrium dilepton production in QCD Kinetic Theory

Phenomenological model for $γ γ^{} \to K K ˉ^{} (892)$ constraining the $f_{1} (1420)$ transition form factor

Affiliations

Scaling of pre-equilibrium dilepton production in QCD Kinetic Theory

Phenomenological model for γγ∗→KKˉ∗(892) constraining the f1​(1420) transition form factor

Affiliations

Phenomenological model for $γ γ^{} \to K K ˉ^{} (892)$ constraining the $f_{1} (1420)$ transition form factor