Year: 2026
Type: preprint
Abstract: We present an analysis of lepton polarization observables in the rare flavor-changing neutral current decays $Λ_b \to Λ\ell^+\ell^-$ and $Λ_b \to Λ^*\ell^+\ell^-$. These decays are driven by the quark-level transition $b \to s\ell^+\ell^-$ and are sensitive to short-distance physics within and beyond the Standard Model. We work within an effective Hamiltonian framework and derive single lepton polarization asymmetries, double lepton polarization asymmetries, and polarized forward-backward asymmetries using the helicity method. The observables are expressed in terms of transversity amplitudes and evaluated using state-of-the-art lattice QCD form factors. We analyze the $q^2$ dependence of several observables for both the ground-state $Λ$ and the excited $Λ^*(1520)$ final states and discuss sensitivities of the observables to chiral structure of the effective operators and complex Wilson coefficients.
Source: arXiv (Cornell University)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2291724845, G2428087542, G6325165843
OpenAlex ID: W7223086090