  Cyclotron resonance in bilayer graphene is studied with weak electron-hole
asymmetry, suggested by experiment, taken into account and with the focus on
many-body corrections that evade Kohn's theorem. It is shown by direct
calculation that the theory remains renormalizable to O(e^2) in the presence of
electron-hole asymmetry parameters, and a general program to carry out
renormalization for graphene under a magnetic field is presented. Inclusion of
electron-hole asymmetry in part improves the theoretical fit to the existing
data and the data appear to indicate the running of the renormalized velocity
factor with the magnetic field, which is a key consequence of renormalization.
