Search for pair production of excited top quarks in the lepton + jets final state
曾衍銘1*, 王大維1, 陳凱風1, Ulysses Grundler1
1物理系, 台灣大學, 台北市, Taiwan
* presenting author:Yeng-Ming Tzeng,
A search is performed for pair-produced spin-3/2 excited top quarks (t*t¯*), each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp collisions at a center-of-mass energy of √s = 8 TeV, selecting events that have a single isolated muon or electron, an imbalance in transverse momentum, and at least six jets, of which one must be compatible with originating from the fragmentation of a b quark. The data, corresponding to an integrated luminosity of 19.5 fb−1, show no significant excess over standard model predictions, and provide a lower limit of 803 GeV at 95% confidence on the mass of the spin-3/2 t* quark in an extension of the Randall-Sundrum model, assuming a 100% branching fraction of its decay into a top quark and a gluon. This is the first search for a spin-3/2 excited top quark performed at the LHC.

Keywords: excited top quark