Executive Summary : | The Standard Model of particle physics has been successful in explaining the interaction between fundamental building blocks of Nature, with the discovery of the Higgs boson being the last remaining particle. However, there are indications that the theory is not complete, such as neutrino oscillations, astrophysical evidence for Dark Matter, and matter-antimatter asymmetry. In the absence of direct evidence of beyond the Standard Model particle, experiments like the Large Hadron Collider (LHC) at CERN have led to an era where new physics can appear as a tiny deviation from the prediction of the Standard Model. In this situation, the rare decay modes of hadrons can play a crucial role, as they are sensitive to the presence of new heavy particles contributing to the modes at the tree level or via loop process.
The proposed project investigates a flavor-changing neutral current decay Bs → φll, where a discrepancy is observed when the theory prediction of the branching fraction is compared to the LHC data. The researchers reevaluate the hadronic parameters, including missing non-local contributions, finite spectator quark mass, and neutral meson mixing contributions. They also focus on another flavor-changing neutral current transition b → d via several modes, which have impressive prospects to be measured at SuperKEKB and future updates of the LHC. |