Charged particle multiplicity in p+Pb collisions in the ATLAS experiment

This presentation describes the study of multiplicity of produced charged particles in p+Pb collisions at the centre-of-mass energy of 5.02 TeV. The particle density was measured in a wide $-2.7 < \eta < 2.7$ range for eight centrality classes using 2.1 million events which were collected during a "pilot run" in September 2012. Due to the difference between proton and lead beam energies, the collisions has a rapidity boost of -0.47 with respect to the ATLAS detector frame of reference.