D_{s}meson leadingtwist distribution amplitude within the QCD sum rules and its application to the B_{s}→D_{s} transition form factor
Abstract
We make a detailed study of the D_{s}meson leadingtwist lightcone distribution amplitude ϕ_{2 ;Ds} by using the QCD sum rules within the framework of the background field theory. To improve the precision, its moments ⟨ξ^{n}⟩_{2 ;Ds} are calculated up to dimensionsix condensates. At the scale μ =2 GeV , we obtain ⟨ξ^{1}⟩_{2 ;Ds}=0.261_{0.020}^{+0.020} , ⟨ξ^{2}⟩_{2 ;Ds}=0.184_{0.012}^{+0.012} , ⟨ξ^{3}⟩_{2 ;Ds}=0.111_{0.012}^{+0.007} , and ⟨ξ^{4}⟩_{2 ;Ds}=0.075_{0.005}^{+0.005} . Using those moments, the ϕ_{2 ;Ds} is then constructed by using the lightcone harmonic oscillator model. As an application, we calculate the transition form factor f_{+B}^{s→Ds}(q^{2}) within the lightcone sum rules (LCSR) approach by using a righthanded chiral current, in which the terms involving ϕ_{2 ;Ds} dominate the LCSR. It is noted that the extrapolated f_{+}^{Bs→Ds}(q^{2}) agrees with the lattice QCD prediction. After extrapolating the transition form factor to the physically allowable q^{2} region, we calculate the branching ratio and the CKM matrix element, which give B (B_{¯}^{s 0}→D_{s}^{+}ℓν_{ℓ})=(2.03_{0.49}^{+0.35})×10^{2} and V_{c b}=(40.00_{4.08}^{+4.93})×10^{3} .
 Publication:

Physical Review D
 Pub Date:
 June 2021
 DOI:
 10.1103/PhysRevD.103.114024
 arXiv:
 arXiv:2104.00180
 Bibcode:
 2021PhRvD.103k4024Z
 Keywords:

 High Energy Physics  Phenomenology