  By considering analytical expressions for the self-energies of intervalley
and intravalley phonons in graphene, we describe the behavior of D, 2D, and
D$'$ Raman bands with changes in doping ($\mu$) and light excitation energy
($E_L$). Comparing the self-energy with the observed $\mu$ dependence of the 2D
bandwidth, we estimate the wavevector $q$ of the constituent intervalley phonon
at $\hbar vq\simeq E_L/1.6$ ($v$ is electron's Fermi velocity) and conclude
that the self-energy makes a major contribution (60%) to the dispersive
behavior of the D and 2D bands. The estimation of $q$ is based on an image of
shifted Dirac cones in which the resonance decay of a phonon satisfying $q >
\omega/v$ ($\omega$ is the phonon frequency) into an electron-hole pair is
suppressed when $\mu < (vq-\omega)/2$. We highlight the fact that the decay of
an intervalley (and intravalley longitudinal optical) phonon with $q=\omega/v$
is strongly suppressed by electron-phonon coupling at an arbitrary $\mu$. This
feature is in contrast to the divergent behavior of an intravalley transverse
optical phonon, which bears a close similarity to the polarization function
relevant to plasmons.
