Searching the inclusive l gamma E-T + b-quark signature for radiative top quark decay and non-standard-model processes

Abstract

In a search for new phenomena in a signature suppressed in the standard model of elementary particles (SM),we compare the inclusive production of events containing a lepton (l), a photon (gamma), significant transverse momentum imbalance (E-T), and a jet identified as containing a b-quark, to SM predictions. The search uses data produced in proton-antiproton collisions at root sp = 1.96 TeV corresponding to 1.9 fb(-1) of integrated luminosity taken with the CDF detector. We find 28 l gamma E-T events versus an expectation of 31.0(-3.5)(+4.1) events. If we further require events to contain at least three jets and large total transverse energy, the largest SM source is radiative top-quark pair production, t (r) over bar + gamma. In the data we observe 16 t (t) over bar gamma candidate events versus an expectation from SM sources of 11.2(-2.1)(+2.3) Assuming the difference between the observed number and the predicted non-top-quark total of 6.8(-2.0)(+2.2) is due to SM top- quark production, we estimate the t (t) over bart cross section to be 0.15 +/- 0.08 pb.