Non-factorisable Contributions of Strong-Penguin Operators in $Λ_b \to Λ\ell^+\ell^-$ Decays

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Hauptverfasser: Feldmann, Thorsten, Gubernari, Nico
Format: Preprint
Veröffentlicht: 2023
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author Feldmann, Thorsten
Gubernari, Nico
author_facet Feldmann, Thorsten
Gubernari, Nico
contents We investigate for the first time a certain class of non-factorisable contributions of the four-quark operators ${\cal O}_{3-6}$ in the weak effective Hamiltonian to the $Λ_b \to Λ\ell^+\ell^-$ decay amplitude. We focus on the case where a virtual photon is radiated from one of the light constituents of the $Λ_b$ baryon, in the kinematic situation of large hadronic recoil with an energetic $Λ$ baryon in the final state. The effect on the suitably defined ``non-local form factors'' is calculated using the light-cone sum rule approach for a correlator with an interpolating current for the light $Λ$ baryon. We find that this approach requires the introduction of new soft functions that generalise the standard light-cone distribution amplitudes (LCDAs) for the heavy $Λ_b$ baryon. We give a heuristic discussion of their properties and a model that relates them to the standard LCDAs. Within this framework, we provide numerical results for the size of the non-local form factors considered.
format Preprint
id arxiv_https___arxiv_org_abs_2312_14146
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Non-factorisable Contributions of Strong-Penguin Operators in $Λ_b \to Λ\ell^+\ell^-$ Decays
Feldmann, Thorsten
Gubernari, Nico
High Energy Physics - Phenomenology
We investigate for the first time a certain class of non-factorisable contributions of the four-quark operators ${\cal O}_{3-6}$ in the weak effective Hamiltonian to the $Λ_b \to Λ\ell^+\ell^-$ decay amplitude. We focus on the case where a virtual photon is radiated from one of the light constituents of the $Λ_b$ baryon, in the kinematic situation of large hadronic recoil with an energetic $Λ$ baryon in the final state. The effect on the suitably defined ``non-local form factors'' is calculated using the light-cone sum rule approach for a correlator with an interpolating current for the light $Λ$ baryon. We find that this approach requires the introduction of new soft functions that generalise the standard light-cone distribution amplitudes (LCDAs) for the heavy $Λ_b$ baryon. We give a heuristic discussion of their properties and a model that relates them to the standard LCDAs. Within this framework, we provide numerical results for the size of the non-local form factors considered.
title Non-factorisable Contributions of Strong-Penguin Operators in $Λ_b \to Λ\ell^+\ell^-$ Decays
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2312.14146