Indications of Suppression of ExcitedΥStates in Pb-Pb Collisions atsNN=2.76  TeV

Abstract

A comparison of the relative yields of Ç resonances in the þ À 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 Çð2SÞ and Çð3SÞ excited states to the Çð1SÞ ground state in Pb-Pb and pp collisions, ½Çð2S þ 3SÞ=Çð1SÞ Pb-Pb =½Çð2S þ 3SÞ=Çð1SÞ pp , is found to be 0:31 þ0:19 À0:15 ðstatÞ AE 0:03ðsystÞ. The probability to obtain the measured value, or lower, if the true double ratio is unity, is calculated to be less than 1%.

Exceptional thermodynamics: the equation of state of G2 gauge theory

“…These findings are derived from the observation of elliptic flow [12][13][14][15][16], electromagnetic spectra [17,18], quarkonium melting [19][20][21][22][23][24][25][26], enhanced strangeness production [27][28][29][30][31][32] and jet quenching [33][34][35][36][37][38][39][40][41][42][43][44]; for a very recent review, see ref. [45].…”

Heavy quark state production in Pb-Pb collisions at s pp = 5.02 $$ \sqrt{s_{pp}}=5.02 $$ TeV

“…A recent CMS result [21], with a correction factor for acceptance and efficiency of the Υ(3S) to the Υ(1S) state, which was estimated to be approximately 0.29 [22], was found to be [1] The studies of Pb-Pb collisions for bottomonium states, which cannot be carried out at RHIC but are an important part of LHC programs, will be carried out in our future research.…”

Prospects for Quarkonium Measurements in p–A and A–A Collisions at the LHC

“…At the LHC, the CMS collaboration provided the first measurements separating the individual ϒ states in A-A collisions [3,4,5] and showing clear evidence for a suppression pattern where the higher mass states are strongly suppressed. However, the combination of the data from CMS [4] measuring in the rapidity range |y| < 2.4 and ALICE [6] measuring in 2.5 < y < 4.0 on the ϒ (1S) production, could not be explained yet in a satisfactory way based on models on the market, see for a discussion e.g.…”

“…Therefore, it was already able to largely profit from the delivered luminosity by the LHC in Run 1. The complete spectrometer is placed behind a hadron absorber during Run 1 and 3 We refer here always only to states below the open charm/beauty threshold. 4 LHCb measured for the first time the lowest mass state in the charmonium system η c in pp collisions by using the pp decay channel [55].…”