Weak radiative decay using light-cone sum rules

Yu-Ji Shi; Zhi-Peng Xing; Ulf-G. Meißner

doi:10.1140/epjc/s10052-023-11362-9

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 224
https://doi.org/10.1140/epjc/s10052-023-11362-9

Regular Article - Theoretical Physics

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

Yu-Ji Shi¹, Zhi-Peng Xing²^b and Ulf-G. Meißner¹^,3^,4

¹ Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn, Germany
² Tsung-Dao Lee Institute, Shanghai Jiao Tong University, 200240, Shanghai, China
³ Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, 52425, Jülich, Germany
⁴ Tbilisi State University, 0186, Tbilisi, Georgia

^b zpxing@sjtu.edu.cn

Received: 10 December 2022
Accepted: 26 February 2023
Published online: 17 March 2023

Abstract

We calculate the decay width of the $Λ_{c}^{+} \to Σ^{+} γ$ $\Lambda _{c}^{+}\rightarrow \Sigma ^{+}\gamma$ 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 $Σ^{+}$ $\Sigma ^+$ 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 $B (Λ_{c}^{+} \to Σ^{+} γ) = 1.03 \pm 0.36 \times 10^{- 4}$ $\mathcal{B}(\Lambda _{c}^{+}\rightarrow \Sigma ^{+}\gamma )=1.03\pm 0.36 \times 10^{-4}$ , which is below the recent upper limits $< 2.6 \times 10^{- 4}$ $<2.6 \times 10^{-4}$ and $< 4.4 \times 10^{- 4}$ $<4.4 \times 10^{-4}$ given by the Belle collaboration and the BESIII collaboration, respectively.

© The Author(s) 2023

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