  We study gravity wave production and baryogenesis at the electroweak phase
transition, in a real singlet scalar extension of the Standard Model, including
vector-like top partners to generate the CP violation needed for electroweak
baryogenesis (EWBG). The singlet makes the phase transition strongly
first-order through its coupling to the Higgs boson, and it spontaneously
breaks CP invariance through a dimension-5 contribution to the top quark mass
term, generated by integrating out the heavy top quark partners. We improve on
previous studies by incorporating updated transport equations, compatible with
large bubble wall velocities. The wall speed and thickness are computed
directly from the microphysical parameters rather than treating them as free
parameters, allowing for a first-principles computation of the baryon
asymmetry. The size of the CP-violating dimension-5 operator needed for EWBG is
constrained by collider, electroweak precision, and renormalization group
running constraints. We identify regions of parameter space that can produce
the observed baryon asymmetry or observable gravitational (GW) wave signals.
Contrary to standard lore, we find that for strong deflagrations, the
efficiencies of large baryon asymmetry production and strong GW signals can be
positively correlated. However we find the overall likelihood of observably
large GW signals to be smaller than estimated in previous studies. In
particular, only detonation-type transitions are predicted to produce
observably large gravitational waves.
