Λ_b → Λℓ⁺ℓ^- and Λ_b → Λ^∗ ℓ⁺ℓ^- decays with polarized leptons

@misc{das2026λℓℓ,
  title = {{$Λ_b \to Λ\ell^+\ell^-$ and $Λ_b \to Λ^\ast \ell^+\ell^-$ decays with polarized leptons}},
  author = {Diganta Das and Vedant Parekh and Ria Sain and Dargi Shameer},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.27015},
  eprint = {2610.27015},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.27015},
}

TY  - UNPB
TI  - Λ_b → Λℓ^+ℓ^- and Λ_b → Λ^∗ ℓ^+ℓ^- decays with polarized leptons
AU  - Diganta Das
AU  - Vedant Parekh
AU  - Ria Sain
AU  - Dargi Shameer
PY  - 2026
DA  - 2026/10/19
PB  - arXiv
DO  - 10.48550/arxiv.2610.27015
UR  - https://arxiv.org/abs/2610.27015
AB  - We present an analysis of lepton polarization observables in the rare flavor-changing neutral current decays Λ_b → Λℓ^+ℓ^- and Λ_b → Λ^*ℓ^+ℓ^-. These decays are driven by the quark-level transition b → sℓ^+ℓ^- 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.
ER  -