Charge-dependent azimuthal particle correlations with respect to the second-order event plane in p-Pb and PbPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV have been studied with the CMS experiment at the LHC. The measurement is performed with a three-particle correlation technique, using two particles with the same or opposite charge within the pseudorapidity range broken vertical bar eta broken vertical bar < 2.4, and a third particle measured in the hadron forward calorimeters (4.4 < broken vertical bar eta broken vertical bar < 5). The observed differences between the same and opposite sign correlations, as functions of multiplicity and. gap between the two charged particles, are of similar magnitude in p-Pb and PbPb collisions at the same multiplicities. These results pose a challenge for the interpretation of charge-dependent azimuthal correlations in heavy ion collisions in terms of the chiral magnetic effect.

Observation of Charge-Dependent Azimuthal Correlations in p-Pb Collisions and Its Implication for the Search for the Chiral Magnetic Effect

ZOTTO, PIERLUIGI;AZZI, PATRIZIA;BENATO, LISA;BISELLO, DARIO;BOLETTI, ALESSIO;CARLIN, ROBERTO;Carvalho Antunes de Oliveira, Alexandra;CHECCHIA, PAOLO;DALL'OSSO, MARTINO;GASPARINI, FABRIZIO;GASPARINI, UGO;GOZZELINO, ANDREA;LACAPRARA, STEFANO;MARGONI, MARTINO;MENEGUZZO, ANNA TERESA;PAZZINI, JACOPO;POZZOBON, NICOLA;RONCHESE, PAOLO;SIMONETTO, FRANCO;TORASSA, EZIO;ZANETTI, MARCO;ZUMERLE, GIANNI;Tosi, M.;Triossi, A.;