We study the hadronic matrix elements describing the Bs→Dsℓνˉℓ decay in and beyond the Standard Model. By using the twisted mass
QCD on the lattice with Nf=2 dynamical flavors we compute the normalization
Gs(1) of the form factor dominating Bs→Dsℓνˉℓ
in the SM. We also make the first lattice determination of F0(q2)/F+(q2)
and FT(q2)/F+(q2) near zero recoil (near qmax2). We briefly
discuss the non-strange case B→Dℓνˉℓ as well.Comment: presented at the 31st International Symposium on Lattice Field Theory
(Lattice 2013), 29 July - 3 August 2013, Mainz, German