Bose-Einstein correlations in pp, pPb, and PbPb collisions at √sNN=0.9–7 TeV

Abstract

Quantum-statistical (Bose-Einstein) two-particle correlations are measured in p p collisions at √ s = 0.9 , 2.76, and 7 TeV, as well as in p Pb and peripheral PbPb collisions at nucleon-nucleon center-of-mass energies of 5.02 and 2.76 TeV, respectively, using the CMS detector at the Large Hadron Collider. Separate analyses are performed for same-sign unidentified charged particles as well as for same-sign pions and kaons identified via their energy loss in the silicon tracker. The characteristics of the one-, two-, and three-dimensional correlation functions are studied as functions of the pair average transverse momentum ( k T ) and the charged-particle multiplicity in the event. For all systems, the extracted correlation radii steadily increase with the event multiplicity, and decrease with increasing k T . The radii are in the range 1–5 fm, the largest values corresponding to very high multiplicity p Pb interactions and to peripheral PbPb collisions with multiplicities similar to those seen in p Pb data. It is also observed that the dependencies of the radii on multiplicity and k T largely factorize. At the same multiplicity, the radii are relatively independent of the colliding system and center-of-mass energy.