Speaker
Alberto Lusiani
(Scuola Normale Superiore and INFN Pisa)
Description
We present a measurement of the decay branching fraction BF(B0 -> D\*- pi+pi-pi+) obtained by using a data sample of about 471 million BBbar pairs collected by the BABAR detector at the PEP-II e+e- collider. This measurement is about 3 times more precise than the current world average value. This decay of the neutral B meson can be used as a normalization channel for the measurement of the ratio BF(B0 -> D\*- tau+ nu) /BF(B0->D\*-pi+pi-pi+), with tau+ -> pi+pi-pi+ nu that can be extracted from hadron colliders, and could help to shed light on the excess, at the more than 3sigma level with respect to the SM prediction, of BF(B0 -> D\*- tau+ nu) as measured by several experiments. In addition, a significantly improved measurement of the 3pi structure in this decay is presented.
