Search for a Very Light CP-Odd Higgs Boson in Top Quark Decays from p(p)over-bar Collisions at root s=1.96 TeV

Abstract

We present the results of a search for a very light CP-odd Higgs boson a01 originating from top quark decays t ! Hb ! WðÞ a01 b, and subsequently decaying into þ. Using a data sample corresponding to an integrated luminosity of 2:7 fb1 collected by the CDF II detector in pp collisions at 1.96 TeV, we perform a search for events containing a lepton, three or more jets, and an additional isolated track with transverse momentum in the range 3 to 20 GeV=c. Observed events are consistent with background sources, and 95% C.L. limits are set on the branching ratio of t ! Hb for various masses of H and a01 .