부산대학교 도서관

A search for resonances decaying to top quark-antiquark pairs is performed using a dilepton þ jets data sample recorded by the CMS experiment at the LHC in pp collisions at ffiffiffi s p ¼ 7 TeV corresponding to an integrated luminosity of 5 : 0fb 1 . No significant deviations from the standard model background are observed. Upper limits are presented for the production cross section times branching fraction of top quark-antiquark resonances for masses from 750 to 3000 GeV. In particular, the existence of a leptophobic topcolor particle Z 0 is excluded at the 95% confidence level for resonance masses M Z 0 < 1 : 3 TeV for Z 0 ¼ 0 : 012 M Z 0 , and M< 1 : 9 TeV for Z 0 ¼ 0 : 10 M Z 0 .