Bose-Einstein correlations in pp, pPb, and PbPb collisions at root s(NN)=0.9-7 TeV
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Abstract
Quantum-statistical (Bose-Einstein) two-particle correlations are measured in (pp) collisions at (\sqrt{s}=0.9), 2.76, and 7 TeV, as well as in (p\mathrm{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\mathrm{Pb}) interactions and to peripheral PbPb collisions with multiplicities similar to those seen in (p\mathrm{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.