First observation of the decay Lb->Dsp

Abstract

We present the first observation of the decay Lb->Dsp with a significance of 20sigma using proton-proton data collected with the Lhcb at sqrt(s)=7 TeV, sqrt(s)=8 TeV, and sqrt(s)=13 TeV, corresponding to a total integrated luminosity of 4.9 fb^(-1). Furthermore, considering the normalisation decay Lb->LcPi, we report a branching fraction of BF(Lb->Dsp)=(10.7+/-1.2)x10^-6 (excluding systematic uncertainties). This result could help understanding the long standing discrepancy on the value of |Vub|.