Coherent ρ0 photoproduction in ultra-peripheral Pb-Pb collisions at √sNN = 2.76 TeV

Abstract

We report the first measurement at the LHC of coherent photoproduction of ρ0 mesons in ultra-peripheral Pb-Pb collisions. The invariant mass and transverse momentum distributions for ρ0 production are studied in the π+π− decay channel at mid-rapidity. The production cross section in the rapidity range |y| < 0.5 is found to be dσ/dy = 425 ± 10 (stat.) +42 (sys.) mb. Coherent ρ0 production is studied with and without requirement −50 of nuclear breakup, and the fractional yields for various breakup scenarios are presented. The results are compared with those from lower energies and with model predictions.