Indications of Suppression of Excited Υ States in Pb-Pb Collisions at √sNN=2.76 TeV
Indications of Suppression of Excited Υ States in Pb-Pb Collisions at √sNN=2.76 TeV
复制标题
DOI：
10.1103/physrevlett.107.052302
复制
发表时间：
2011-07-28
影响因子：
8.6
通讯作者：
Weinberg, M.
中科院分区：
文献类型：
--
作者：
Chatrchyan, S.;Khachatryan, V.;Weinberg, M.
利用LHC CMS探测器收集的数据，对Pb-Pb碰撞和pp碰撞中μ（+）μ（-）衰变通道中的Uppersonal共振的相对产额进行了比较，每个核子对的质心能量为2.76TeV。利用横动量大于4GeV/c，赝快度小于2.4的μ子，计算了Pb-Pb和pp碰撞中Uppermands（2S）和Uppermands（3S）激发态与Uppermands（1 S）基态的双比，[Uppermands（2S + 3S）/Uppermands（1 S）]（Pb-Pb）/[Uppermands 2S + 3S）/Uppermands（1 S）]（pp），发现其为0.31（-0.15）（+0.19）（stat_ +/- 0.03（syst）.如果真双比为1，则获得测量值或更低值的概率计算为小于1%。
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%.