Impact of B → K∗0`+` − on the New Physics search in B → K∗`+` − decay

We discuss the uncertainty related to the amount of unwanted B → K∗0 (Kpi)`+` − events in the sample of B → K∗(Kpi)`+` − ones. Those events can increase the measured differential decay rate by up to 10 % in the low q2 region, and can be a source of non-negligible uncertainty in the full angular distribution of the B → K∗(Kpi)`+` − decay. Although the transverse asymmetries should be unaffected by the presence of the S-wave Kpi pairs, coming from the scalar K∗0 meson, we show that in practice, their normalization might be sensitive to those events and could entail a sizable uncertainty in transverse asymmetries around q2 = 2 GeV2. For other q2’s that error is under 10%.