Hammering B → D(∗)τν with a Combined Analysis of B → D(∗)lν

by Dean Robinson (UC Berkeley)

Thursday 11 May 2017, 13:15 → 14:15 Europe/Zurich

4/2-037 - TH meeting room (CERN)

We'll discuss a novel combined fit to the semileptonic $B \to D$ and $D^*$ decay distributions, using an approach that consistently includes subleading corrections in the heavy quark effective theory. This fit provides new SM (or NP) predictions for the semitauonic rates, that are the most precise to date, and determines the CKM matrix element |Vcb|. Along the way, I'll provide an overview of the ingredients that are required to generate SM or NP predictions for the anomalous R(D) or R(D^*) ratios. Interpretation of the current experimental results for these ratios in terms of specific NP theories is complicated by the need to account for both $\tau$ and $D^*$ interference effects as well as phase space cuts on the detector-visible final states. A software tool is being developed for experimental software pipelines to permit the systematic and efficient identification of what NP might be responsible for the anomalous R(D) and R(D^*) ratios, using recently computed compact amplitude expressions for the 4,5 or 6-body semitauonic B decays.