  We study fluctuations of a U(1) gauge field on the worldvolume of Nf probe
D7-branes in the background of Nc black D3-branes with a finite baryon density.
The choice of mode corresponds to vector mesons in the dual gauge theory whose
mass and lifetime can be determined by a study of the quasinormal modes. The
speed of propagation of these holographic mesons at large momenta is studied
from the dispersion relations of the quasinormal modes of the system.
