▎ 摘　　要

We study the relaxation dynamics of the electron system in graphene flakes under a Landau quantization regime using an approach of time-resolved Raman scattering. The nonresonant character of the experiment allows us to analyze the field dependence of the relaxation rate. Our results clearly evidence a sharp increase in the relaxation rate upon the resonance between the energy of the Landau transition and the G band and shed light on the relaxation mechanism of the Landau-quantized electrons in graphene beyond the previously studied Auger scattering.