  We investigate intrinsic and extrinsic decay of edge magnetoplasmons (EMPs)
in graphene quantum Hall (QH) systems by high-frequency electronic
measurements. From EMP resonances in disk shaped graphene, we show that the
dispersion relation of EMPs is nonlinear due to interactions, giving rise to
intrinsic decay of EMP wavepacket. We also identify extrinsic dissipation
mechanisms due to interaction with localized states in bulk graphene from the
decay time of EMP wavepackets. We indicate that, owing to the unique linear and
gapless band structure, EMP dissipation in graphene can be lower than that in
GaAs systems.
