Chatrchyan, S;
Khachatryan, V;
Sirunyan, AM;
Tumasyan, A;
Adam, W;
Bergauer, T;
Dragicevic, M;
... CMS Collaboration; + view all
(2011)
Indications of Suppression of Excited Upsilon States in Pb-Pb Collisions at root(NN)-N-s=2.76 TeV.
PHYS REV LETT
, 107
(5)
, Article 052302. 10.1103/PhysRevLett.107.052302.
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Abstract
A comparison of the relative yields of Upsilon resonances in the mu(+)mu(-) decay channel in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair of 2.76 TeV is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4 GeV/c and pseudorapidity below 2.4, the double ratio of the Upsilon(2S) and Upsilon(3S) excited states to the Upsilon(1S) ground state in Pb-Pb and pp collisions, [Upsilon(2S + 3S)/Upsilon(1S)](Pb-Pb) /[Upsilon 2S + 3S)/Upsilon(1S)](pp), is found to be 0.31(-0.15)(+0.19) (stat_ +/- 0.03(syst). The probability to obtain the measured value, or lower, if the true double ratio is unity, is calculated to be less than 1%.
Type: | Article |
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Title: | Indications of Suppression of Excited Upsilon States in Pb-Pb Collisions at root(NN)-N-s=2.76 TeV |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1103/PhysRevLett.107.052302 |
Publisher version: | http://dx.doi.org/10.1103/PhysRevLett.107.052302 |
Language: | English |
Additional information: | Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. © 2011 CERN, for the CMS Collaboration |
Keywords: | QUARK-GLUON PLASMA, HEAVY, DENSITY, QCD |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1324755 |
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