Measurement of Long-Range Near-Side Two-Particle Angular Correlations in pp Collisions at s =13 TeV

Results on two-particle angular correlations for charged particles produced in pp collisions at a center-of-mass energy of 13 TeV are presented. The data were taken with the CMS detector at the LHC and correspond to an integrated luminosity of about 270  nb^(−1). The correlations are studied over a broad range of pseudorapidity (|η| 2.0), near-side (Δϕ≈0) structure emerges in the two-particle Δη–Δϕ correlation functions. The magnitude of the correlation exhibits a pronounced maximum in the range 1.0charged particle multiplicity, with an overall correlation strength similar to that found in earlier pp data at √s=7  TeV. The present measurement extends the study of near-side long-range correlations up to charged particle multiplicities N_(ch)∼180, a region so far unexplored in pp collisions. The observed long-range correlations are compared to those seen in pp, pPb, and PbPb collisions at lower collision energies.