Weak radiative decay $$\Lambda _{c}^{+}\rightarrow \Sigma ^{+}\gamma $$ using light-cone sum rules

Abstract

AbstractWe calculate the decay width of the $$\Lambda _{c}^{+}\rightarrow \Sigma ^{+}\gamma $$ Λ c + → Σ + γ using light-cone sum rules. For the initial quark radiation an effective Hamiltonian is constructed, where the internal quark line shrinks to a point. The final quark radiation is studied within the full theory. The leading twist light-cone distribution amplitudes of the $$\Sigma ^+$$ Σ + serve as the non-perturbative input for the sum rules calculation, and the perturbative kernel is calculated at leading order. The branching fraction we obtain is $$\mathcal{B}(\Lambda _{c}^{+}\rightarrow \Sigma ^{+}\gamma )=1.03\pm 0.36 \times 10^{-4}$$ B ( Λ c + → Σ + γ ) = 1.03 ± 0.36 × 10 - 4 , which is below the recent upper limits $$<2.6 \times 10^{-4}$$ < 2.6 × 10 - 4 and $$<4.4 \times 10^{-4}$$ < 4.4 × 10 - 4 given by the Belle collaboration and the BESIII collaboration, respectively.