Point of order! A massive neutrino is a WIMP. “Weakly Interacting”—that’s neutrino to you—“Massive Particle”.
Well, but “massive” in WIMP usually means very massive (i.e. non-relativistic at T = 2.7 K). As far as gravitational effects, particles with non-zero mass but ultrarelativistic speeds behave very much like photons AFAIK.
Well, but “massive” in WIMP usually means very massive (i.e. non-relativistic at T = 2.7 K). As far as gravitational effects, particles with non-zero mass but ultrarelativistic speeds behave very much like photons AFAIK.