Abstract:
Short range correlations of identified charged hadrons in pp ($\sqrt{s} =$ 0.9, 2.76, and 7 TeV), pPb ($\sqrt{s_{NN}} =$ 5.02 TeV), and peripheral PbPb collisions ($\sqrt{s_{NN}} =$ 2.76 TeV) are studied with the CMS detector at the LHC. Charged pions and kaons at low $p_\text{T}$ and in laboratory pseudorapidity $\vert \eta \vert < 1$ are identified via their energy loss in the silicon tracker. The twoparticle correlation functions show effects of quantum statistics, Coulomb interaction, and also indicate the role of multibody resonance decays and minijets. The characteristics of the one, two, and threedimensional correlation functions are studied as a function of the transverse pair momentum and of the chargedparticle multiplicity of the event. The extracted radii are in the range 15 fm, reaching the highest values for very high multiplicity pPb interactions and for similar multiplicity PbPb collisions. For all systems and multiplicities, the radii decrease with increasing $k_\text{T}$. The dependence of the radii on the multiplicity and $k_\text{T}$ largely factorizes. For some regions of multiplicity and $k_\text{T}$, the radii are relatively insensitive to the choice of colliding system and centerofmass energy.
