Photoproduction ofρ0mesons in ultraperipheral heavy ion collisions at energies available at the BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC)

Abstract

We investigate the photoproduction of ρ mesons in ultraperipheral heavy ion collisions at RHIC and LHC energies in the dipole approach and within two phenomenological models based on the the Color Glass Condensate (CGC) formalism. We estimate the integrated cross section and rapidity distribution for meson production and compare our predictions with the data from the STAR collaboration. In particular, we demonstrate that the total cross section at RHIC is strongly dependent on the energy behavior of the dipole-target cross section at low energies, which is not well determined in the dipole approach. In contrast, the predictions at midrapidities at RHIC and in the full rapidity at LHC are under theoretical control and can be used to test the QCD dynamics at high energies.

Vector meson production in coherent hadronic interactions: Update on predictions for energies available at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider

“…Before presenting our results, in what follows we will introduce a very brief explanation about the models used in our calculations and refer to Refs. [9,10] for more complete details.Lets consider the hadron-hadron interaction at large impact parameter (b > 2R h , where R h is the hadron radius) and at ultrarelativistic energies. In this regime we expect the electromagnetic interaction to be dominant.…”

“…[2]). In recent years we have proposed the analysis of coherent collisions in hadronic interactions as an alternative way to study the QCD dynamics at high energies [3][4][5][6][7][8][9][10][11]. The basic idea in coherent hadronic collisions is that the total cross section for a given process can be factorized in terms of the equivalent flux of photons into the hadron projectile and the photon-photon or photon-target production cross section.…”

“…In particular, we will update Refs. [9,10], where we have studied the J / , ϒ, and ρ production at RHIC and for the full energies of the LHC. Moreover, for the first time, we will present our predictions for the rapidity dependence of the ratio between the J / and ρ cross sections at RHIC energies, which is currently under analysis by the STAR collaboration.…”

“…Before presenting our results, in what follows we will introduce a very brief explanation about the models used in our calculations and refer to Refs. [9,10] for more complete details.…”

“…As in Refs. [9,10] we will assume that in the case of photon-nucleus interactions the scattering amplitude is given by [21] N (x, r, b) where T A (b) is the nuclear profile function (obtained from a three-parameter Fermi distribution for the nuclear density), and the dipole-nucleon cross section is taken from the Iancu, Itakura, and Munier (IIM) model [22]. In the case of photon-proton interactions we will use the nonforward saturation model of Ref.…”