The electromagnetic decays of B c ± (2 S )

We calculate the electromagnetic (em) decay widths of the b ± (2s) meson, which is observed recently by the atlas collaboration. the main em decay channels of this particle are 13 s 1 γ and 1pγ, which, in literature, are estimated to have the branching ratio of about 1/10. in this work, we get the partial decay widths: γ(21 s 0 → 13 s 1 γ) = 0.192 kev, γ(21 s 0 → 1p 1 γ) = 2.24 kev and γ(21 s 0 → 1p 1 ′ γ) = 11.4 kev. in the calculation, the instantaneous approximated bethe-salpeter method is used. for the p-wave b c mesons, the wave functions are given by mixing the 3 p 1 and 1 p 1 states. within the mandelstam formalism, the decay amplitude is given, which includes the relativistic corrections.