Mainz 2012 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 46: Poster – Schwerionenkollisionen und QCD Phasen

HK 46.1: Poster

Donnerstag, 22. März 2012, 14:00–16:00, P Foyer

Gluodissociation of bottomonium states in PbPb collisions at LHC energies — •Felix Brezinski and Georg Wolschin — Institut für Theoretische Physik der Universität Heidelberg, Philosophenweg 16, D-69120 Heidelberg, Germany, EU

We suggest that gluon-induced dissociation and screening of the Υ(nS) states explain the suppression of the Υ(2S+3S) states relative to the Υ(1S) ground state that has been observed by CMS in PbPb collisions at √s_NN = 2.76 TeV at the CERN LHC. The minimum-bias gluodissociation cross sections of the 1S - 3S states are calculated using a screened Cornell potential and a thermal gluon distribution. The 3S state dissolves due to screening before sizeable gluodissociation occurs, but for the 2S and 1S states there is an interplay between screening, gluodissociation, and feed-down from the χ_b(2P) and χ_b(1P) states. The calculated suppression of the Υ(2S) and Υ(3S) states relative to Υ(1S) is consistent with the CMS result, but allows for additional suppression mechanisms. The Υ(1S) suppression through gluodissociation is in excellent agreement with the CMS data.