  Vector mesons containing light quarks are thought to have their masses
reduced in dense nuclear matter, sacrificing some of their energy to the scalar
field which becomes appreciable at finite baryon density. Model calculations
find masses which fall by a couple tens of percents in normal nuclear matter,
and by several hundred MeV in dense matter. We estimate the collision rate for
rho mesons in such a scenario and at finite temperature. Compared to its
free-mass value, the collision rate changes by nearly a factor of two both
above and below, depending on the density. This collision broadening effect
could be important for estimates of low-mass dilepton production in heavy-ion
collisions.
