  We study the process pp -> t tbar H at sqrt(s)=14 TeV where H -> WW. We focus
on final states that include three or four leptons. Signal and background
samples are generated at leading order (LO) and normalized to next-to-leading
order (NLO) calculations. We employ the "Snowmass" detector simulation and
event reconstruction. Cuts are selected which provide a substantial signal
yield while suppressing the main backgrounds. Systematic uncertainties are
estimated for the overall normalization of signal and background processes.
With no improvement in the current theoretical uncertainties on sigma(t tbar
H), we project a precision on a top quark Yukawa coupling of approximately 16%
in 300 fb^-1 and 9% in 3000 fb^-1. If the theoretical uncertainties are halved,
these improve to 14% and 6%, respectively.
