Abstract
The shape of the {B}_s^0to {D}_s^{ast -}{mu}^{+}{nu}_{mu } differential decay rate is obtained as a function of the hadron recoil parameter using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb−1 collected by the LHCb detector. The {B}_s^0to {D}_s^{ast -}{mu}^{+}{nu}_{mu } decay is reconstructed through the decays {D}_s^{ast -}to {D}_s^{-}gamma and {D}_s^{-}to {K}^{-}{K}^{+}{pi}^{-} . The differential decay rate is fitted with the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) parametrisations of the form factors, and the relevant quantities for both are extracted.
Highlights
The LHCb collaboration has measured |Vcb| using Bs0 → Ds(∗)−μ+νμ decays1 with two form-factor parametrisations, giving consistent results [7]
This paper reports the first measurement of the shape of the differential decay rate of the Bs0 → Ds∗−μ+νμ decay as a function of the hadronic recoil parameter w = vBs0 · vDs∗−, where vBs0 and vDs∗− are the four-vector velocities of the Bs0 and Ds∗− mesons, respectively
The unfolding procedure adopted is based on the singular value decomposition (SVD) method [55] using the RooUnfold package implemented in the Root package [56]
Summary
For the CLN parametrisation [10], the helicity amplitudes H0, H+, H− and Ht can be written in terms of the form factors A1(w), V (w), A2(w) and A0(w) as. In the CLN parametrisation, the leading form factor and the three ratios are parametrised in terms of w as hA1(w) = hA1(1)[1 − 8ρ2z(w) + (53ρ2 − 15)z2(w) − (231ρ2 − 91)z3(w)] , R0(w) = R0(1) − 0.11(w − 1) + 0.01(w − 1) , R1(w) = R1(1) − 0.12(w − 1) + 0.05(w − 1) , R2(w) = R2(1) + 0.11(w − 1) − 0.06(w − 1)2 ,. Where the coefficients, originally calculated for B decays, are assumed to be the same for. As this analysis is only sensitive to the shape of the form-factor parametrisation the term hA1(1) is absorbed in the normalisation. The slope, ρ2, of hA1(w) is the only parameter fitted in this parametrisation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
