Towards a model-independent analysis of rareB decays

Abstract

Motivated by the experimental accessibility of rareB decays in the ongoing and planned experiments, we propose to undertake a model-independent analysis of the inclusive decay rates and distributions in the processesB→X _s γ andB→X _s ℓ⁺ℓ⁻ (B=B ^± orB ⁰_d ). We show how measurements of the decay rates and distributions in these processes would allow us to extract the magnitude and sign of the dominant Wilson coefficients of the magnetic moment operator$m_b \bar s_L \sigma _{\mu v} b_R F^{\mu v}$ and the fourfermion operators$(\bar s_L \gamma _\mu b_L )(\bar \ell \gamma ^\mu \ell )$ and$(\bar s_L \gamma _\mu b_L )(\bar \ell \gamma ^\mu \gamma ^5 \ell )$. Non-standard-model effects could thus manifest themselves at low energy in rareB decays through the Wilson coefficient having values distinctly different from their standard-model counterparts. We illustrate this possibility using the examples of the two-doublet Higgs models and the minimal supersymmetric models. The dilepton invariant mass spectrum and the forward-backward asymmetry of ℓ⁺ in the centre-of-mass system of the dilepton pair in the decayB→X _s ℓ⁺ℓ⁻ are also worked out for the standard model and some representative solutions for the other two models.