Form factors of B, Bs → η(′) and D, Ds → η(′) transitions from QCD light-cone sum rules

In the framework of the QCD light-cone sum rules (LCSRs) we present the analysis of all B, Bs → η(′) and D, Ds → η(′) form factors (f+, f0 and fT) by including mη′2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {m}_{\eta^{\left(\prime \right)}}^2 $$\end{document} corrections in the leading (up to the twist-four) and next-to-leading order (up to the twist-three) in QCD, and two-gluon contributions to the form factors at the leading twist. The SU(3)-flavour breaking corrections and the axial anomaly contributions to the distribution amplitudes are also consistently taken into account. The complete results for the f0 and fT form factors of B, Bs → η(′) and D, Ds → η(′) relevant for processes like B → η(′)τντ or Bs → η(′)l+l− are given for the first time, as well as the two-gluon contribution to the tensor form factors. The values obtained for the f+ form factors are as follows: fBη+0=0.168−0.047+0.042,fBsη+0=0.212−0.013+0.015,fBη′+0=0.130−0.032+0.036,fBsη′+0=0.252−0.020+0.023\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {f}_{B\eta}^{+}(0)=0.{168}_{-0.047}^{+0.042},\left|{f}_{B_s\eta}^{+}(0)\right|=0.{212}_{-0.013}^{+0.015},{f}_{B\eta \prime}^{+}(0)=0.13{0}_{-0.032}^{+0.036},{f}_{B_s\eta \prime}^{+}(0)=0.{252}_{-0.020}^{+0.023} $$\end{document} and fDη+0=0.429−0.141+0.165,fDsη+0=0.495−0.029+0.030,fDη′+0=0.292−0.104+0.113,fDsη′+0=0.558−0.045+0.047\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {f}_{D\eta}^{+}(0)=0.{429}_{-0.141}^{+0.165},\left|{f}_{D_s\eta}^{+}(0)\right|={0.495}_{-0.029}^{+0.030},{f}_{D\eta \prime}^{+}(0)={0.292}_{-0.104}^{+0.113},{f}_{D_s\eta \prime}^{+}(0)={0.558}_{-0.045}^{+0.047} $$\end{document}. Also phenomenological predictions for semileptonic B, Bs → η(′) and D, Ds → η(′) decay modes are given.