Search for new physics with rare beauty decays at the LHC – SoRBeT

Fundamental constituents of matter and interactions between them are well described by the Standard Model of particle physics. However, some of the most important questions remain unanswered by this theory and a large consensus exists that a new physics beyond the standard model should manifest itself at higher energies. New physics is extensively searched for at the LHC but no hints of the existence of new physics particles have been found so far. Rare decays of B mesons, especially flavor changing neutral currents, are among the most promising channels to reveal the presence of new physics.
In this project, we propose to study the rare decays of B mesons into tau leptons with the LHCb detector. Contrary to the rare decays with muons in the final state, they are still largely unexplored experimentally, mainly because of the challenging reconstruction of taus. They are however of prime interest to test lepton universality, a signature of the standard model. The first goal of the present project is the search for the Bs mesons decaying into two tau leptons. A research program is established in order to measure the branching ratio of this decay. The tools and expertise developed for this analysis will be adapted to study other decay channels including taus in the final state. The feasibility study of such decays, like B -> K* tau tau or the lepton flavor violating mode B -> tau mu, constitutes the second major goal of this project.