CMS-PAS-FSQ-15-002

CMS-PAS-FSQ-15-002
Observation of long-range near-side two-particle correlations in pp collisions at $\sqrt{s} =$ 13 TeV
CMS Collaboration
September 2015

Abstract: 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 ( $\|\eta\|<$ 2.4) and over the full azimuth ( $\phi$ ) as a function of charged particle multiplicity and transverse momentum ( $p_{\mathrm{T}}$ ). In high-multiplicity events, a long-range ( $\|\Delta\eta\|>$ 2.0), near-side ( $\Delta\phi\approx$ 0) structure emerges in the two-particle $\Delta\eta$ - $\Delta\phi$ correlation functions. The observed correlations resemble the long-range correlations seen in high-multiplicity pp, pPb and PbPb collisions at lower collision energies. The magnitude of the correlation exhibits a pronounced maximum in the range 1.0 $< p_{\mathrm{T}} <$ 2.0 GeV and an approximately linear increase with the charged particle multiplicity. The overall correlation strength at $\sqrt{s} =$ 13 TeV is similar to that found in earlier pp data at $\sqrt{s} =$ 7 TeV, but is measured up to much higher multiplicity values.
Links: CDS record (PDF) ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; These preliminary results are superseded in this paper, PRL 116 (2016) 172302. The superseded preliminary plots can be found here.

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