CMS-PAS-BPH-14-009

CMS-PAS-BPH-14-009
Dependence of the $\Upsilon$ (nS) production ratios on charged particle multiplicity in pp collisions at $\sqrt{s}=$ 7 TeV
CMS Collaboration
October 2016

Abstract: The ratios of the cross section of the $\Upsilon$ (nS) mesons with $\|y\|<1.2$ are studied as a function of the number of charged particles with $p_{\mathrm{T}}>$ 0.4 GeV and $\|\eta\|<$ 2.4 produced in pp collisions at $\sqrt{s}=$ 7 TeV. Evidence of a decrease of the ratios between the higher and the lower mass states is observed, that is more pronounced at lower $p_{\mathrm{T}}$ . For $\Upsilon$ (nS) mesons of transverse momentum greater than 7 GeV, this effect is studied as a function of the underlying event sphericity, and of the distribution of charged particles with respect to the $\Upsilon$ (nS) direction.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 11 (2020) 001. The superseded preliminary plots can be found here.

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