B->Vll at small dilepton invariant mass, power corrections, and new physics

by Sebastian Jäger (Sussex University)

Monday 11 Mar 2013, 16:30 → 17:30 Europe/Berlin

bldg. 2a, SR 2 (DESY Hamburg)

Rare B decays provide powerful probes of new degrees of freedom at the TeV scale and beyond. I will review the basic theory of B decays, and then in more detail the helicity structure of the rare semileptonic decays B->V l l. In particular, I will present new work on controlling long-distance charm and light quark loop effects. Our treatment is more conservative and robust than the prevailing procedure based on QCD factorization alone; nevertheless we find that a certain helicity hierarchy survives and implies that two observables constructed from the angular distribution remain theoretically extremely clean. We also find that this is true all the way down to the endpoint of the dilepton invariant mass spectrum. I discuss the excellent sensitivity to right-handed currents that this implies.