Indications of Suppression of Excited Upsilon States in Pb-Pb Collisions at root(s)NN=2.76 TeV

• Main Authors: Alver, Burak Han (Contributor), Bauer, Gerry P. (Contributor), Bendavid, Joshua L. (Contributor), Busza, Wit (Contributor), Butz, Erik M. (Contributor), Cali, Ivan Amos (Contributor), Chan, M. (Contributor), Dutta, Valentina (Contributor), Everaerts, Pieter Bruno Bart (Contributor), Gomez-Ceballos, Guillelmo (Contributor), Goncharov, Maxim (Contributor), Hahn, Kristian Allan (Contributor), Harris, P. (Contributor), Kim, Y. (Contributor), Klute, Markus (Contributor), Lee, Y. J. (Contributor), Li, W. (Contributor), Loizides, Constantin (Contributor), Luckey, P. David, Jr (Contributor), Ma, Teng (Contributor), Nahn, Steven (Contributor), Paus, Christoph M. E. (Contributor), Ralph, Duncan Kelley (Contributor), Roland, Christof E. (Contributor), Roland, Gunther M. (Contributor), Stephans, George S. F. (Contributor), Stockli, F. (Contributor), Sumorok, Konstanty C. (Contributor), Sung, Kevin Kai Hong (Contributor), Velicanu, Dragos Alexandru (Contributor), Wenger, Edward Allen (Contributor), Xie, Si (Contributor), Yang, M. (Contributor), Yilmaz, Yetkin (Contributor), Zanetti, Marco (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2011-11-09T20:01:17Z.
• Subjects: Article
• Online Access: Get fulltext

A comparison of the relative yields of Υ resonances in the μ[superscript +]μ[superscript -] 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 Υ(2S) and Υ(3S) excited states to the Υ(1S) ground state in Pb-Pb and pp collisions, [Υ(2S+3S)/Υ(1S)][subscript Pb-Pb]/[Υ(2S+3S)/Υ(1S)][subscript pp], is found to be 0.31[subscript -0.15][superscript +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%.
United States. Dept. of Energy
National Science Foundation (U.S.)
Alfred P. Sloan Foundation