▎ 摘　　要

An ultrahigh-magnetic field cyclotron resonance in monolayer epitaxial graphene resolves split peaks in 300-500 T of the magnetic field, generated by the electromagnetic flux compression 1000-T-class megagauss generator. The peak splitting observed is most probably evidence of electron-hole symmetry breaking of Dirac relativistic electrons in graphene. Moreover, the observed asymmetry of absorption intensity between the split peaks is a strong indication of mode repulsion induced by the electron-electron correlation.