Understanding Dilepton Production in Heavy Ion Collisions by Vector Mesons of Different Varieties

TL;DR

This paper presents a schematic model based on hadronic freedom and holographic QCD to describe dilepton production in heavy ion collisions, emphasizing the role of transient rho mesons and their insensitivity to Brown-Rho scaling.

Contribution

It introduces a novel schematic model combining hadronic freedom, holographic QCD, and dispersion relations to explain dilepton production mechanisms.

Findings

Dileptons below 770 MeV mainly originate from pion-composites.

Dileptons are largely insensitive to Brown-Rho scaling effects.

The model successfully describes dilepton spectra observed at PHENIX/RHIC.

Abstract

A simple schematic model anchored on the notion of hadronic freedom inferred from hidden local symmetry in the vector manifestation, the infinite tower of vector mesons in holographic QCD and "stickiness" of $\pi\pi$ interactions inferred from dispersion relations is used to describe the dileptons produced in relativistic heavy ion collisions at PHENIX/RHIC. It is shown that due to the near "blindness" of dileptons to Brown-Rho scaling, those dileptons with invariant mass less than $m_\rho=770$ MeV come mostly from pion-composites that we interpret as "transient $\rho$'s."