Study of radiative leptonic D meson decays

We study the radiative leptonic D meson decays of D-(s)(+) --> l(+)nu (l)ga mma (l = e, mu, tau), D-0 --> <<nu>(nu )over bar>gamma and D-0 --> l(+)l(-) gamma (l = e, mu) within the light front quark model. In the standard mode l, we find that the decay branching ratios of D(s)+ --> e(+)nu (e)gamma, D- (s)(+) --> mu (+)nu (mu)gamma and D-(s)(+) --> tau (+)nu (tau)gamma are 6.9 x 10(-6) (7.7 x 10(-5)), 2.5 x 10(-5) (2.6 x 10(-4)), and 6.0 x 10(-6) (3. 2 x 10(-) (4)), and that of D-0 --> l(+)l(-)gamma (l = e,mu) and D-0 --> << nu>(nu )over bar>gamma are 6.3 x 10(-11) and 2.7 x 10(-16), respectively.