Radiative decays of heavy-light mesons and the f H , H ∗ , H 1 T $$ {f}_{H,{H}^{\ast },{H}_1}^{(T)} $$ decay constants

Abstract

Abstract The on-shell matrix elements, or couplings g H H ∗ H 1 γ $$ {g}_{H{H}^{\ast}\left({H}_1\right)\upgamma} $$ , describing the B D q ∗ $$ B{(D)}_q^{\ast } $$ → B(D) q γ and B 1q → B q γ (q = u, d, s) radiative decays, are determined from light-cone sum rules at next-to-leading order for the first time. Two different interpolating operators are used for the vector meson, providing additional robustness to our results. For the D *-meson, where some rates are experimentally known, agreement is found. The couplings are of additional interest as they govern the lowest pole residue in the B(D) → γ form factors which in turn are connected to QED-corrections in leptonic decays B(D) → ℓ ν ¯ $$ \overline{\nu} $$ . Since the couplings and residues are related by the decay constants f H ∗ H 1 $$ {f}_{H^{\ast}\left({H}_1\right)} $$ and f H ∗ H 1 T $$ {f}_{H^{\ast}\left({H}_1\right)}^T $$ , we determine them at next-leading order as a by-product. The quantities f H ∗ T f H 1 T $$ \left\{{f}_{H^{\ast}}^T,{f}_{H_1}^T\right\} $$ have not previously been subjected to a QCD sum rule determination. All results are compared with the existing experimental and theoretical literature.

Keywords

• NLO Computations
• QCD Phenomenology