Measurement of the shape of the $ {B}_s^0\to {D}_s^{\ast -}{\mu}^{+}{\nu}_{\mu } $ differential decay rate

The shape of the $ {B}_s^0\to {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^0\to {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.[graphic not available: see fulltext]