CERN Accelerating science

CMS Note
Report number	CMS-CR-2012-258
Title	Detailed measurements of bottomonium suppression in PbPb collisions at 2.76 TeV with CMS
Author(s)	Breto Rangel, Guillermo (CERN)
Collaboration	on behalf of the CMS Collaboration
Publication	2013
Imprint	06 Oct 2012
Number of pages	5
In:	Nucl. Phys. A 904-905 (2013) pp.615c-618c
In:	23rd International Conference on Ultrarelativistic Nucleus-Nucleus Collisions, Washington, DC, USA, 13 - 18 Aug 2012, pp.615c-618c
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Abstract	The three $\Upsilon(1S, 2S, 3S)$ states can be separated using the CMS experimental apparatus via their dimuon decays in both pp and heavy-ion collisions. A suppression of the $\Upsilon(1S)$, $\Upsilon(2S)$ and $\Upsilon(3S)$ mesons is observed in PbPb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. Furthermore, a suppression of the excited $\Upsilon$ states has been measured with respect to the $\Upsilon$ ground state, expressed as a double ratio [$\Upsilon(nS)$/$\Upsilon(1S)$]$_{PbPb}$ / [$\Upsilon(nS)$/$\Upsilon(1S)$]$_{pp}$ with n = 2, 3, and 2 + 3. The centrality dependence of the double ratio, as well as the nuclear modification factors ($R_{AA}$) of the $\Upsilon(1S)$ and $\Upsilon(2S)$ states are presented as a function of collision centrality, based on the analysis of the full data sample collected during the 2011 PbPb run, which corresponds to an integrated luminosity of 150 $\mu b^{-1}$.
Copyright/License	Preprint: (License: CC-BY-4.0)

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