  The bubble wall velocity is essential for the phase transition dynamics in
the early universe and its cosmological implications, such as the energy budget
of phase transition gravitational wave and electroweak baryogenesis. One key
factor to determine the wall velocity is the collision term that quantifies the
interactions between the massive particles in the plasma and the bubble wall.
We improve the calculations of the collision term beyond the leading-log
approximation, and further obtain more precise bubble wall velocity for a
representative effective model.
