Radiative decays D?_(s)D_(s) in covariant confined quark model

Radiative decays D-(s)(& lowast;)-> D-(s)gamma are revisited in light of new experimental data from the BaBar and BESIII Collaborations. The radiative couplings gD & lowast;D gamma encoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us. We compare our results with other theoretical studies and experimental data. The couplings (in GeV-1) |g(D & lowast;+D+gamma)|=0.45(9) and |g(D & lowast;0D0 gamma)|=1.72(34) calculated in our model agree with the corresponding experimental data |gD(& lowast;+D+gamma)|=0.47(7) and |g(D & lowast;0D0 gamma)|=1.77(16). The most interesting case is the decay D-s(& lowast;)-> D-s gamma, for which a recent prediction based on light-cone sum rules at next-to-leading order |g(D & lowast;sDs gamma)|=0.60(19) deviates from the first (and only to date) lattice QCD result |g(D & lowast;sDs gamma)|=0.11(2) at nearly 3 sigma. Our calculation yields |g(D & lowast;sDs gamma)|=0.29(6), which falls somehow between the two mentioned results, although it is larger than those predicted in other studies using quark models or QCD sum rules.