ExclusiveD_s→ (η, η′)lν decays in light-cone QCD

Abstract

Probing thess content of the η and η ′ mesons and considering mixing between these states as well as gluonic contributions, the form factors responsible for semileptonic D s → (η, η ′ )lν transitions are calculated via light cone QCD sum rules. Corresponding branching fractions and their ratio for different mixing angles are also obtained. Our results are in a good consistency with experimental data as well as predictions of other nonperturbative approaches.

Light-cone sum rules for theD(s)→η(′)lνlform fact

“…To achieve this goal we made heavy use of NLO results existing in the literature [16,17]. Our results for the decay formfactors agree within uncertainties with those of [15]. While this is encouraging, we also feel that it is somewhat fortuitous, because we have some doubts concerning the benefits of the chiral currents used in that work, since they eliminate important nonperturbative information and do not couple only to the pseudoscalar mesons in the hadronic sum.…”

“…Table IV shows our results at q 2 = 0. [15]. Orange Point: corrected lattice result from [47] in accordance with a private communication from the author.…”

“…As for all three cases (D, D s and B decays) the required increase in experimental accuracy looks very much feasible for next-generation experiments and we hope that in a few years from now data for this complete set of meson decays will provide undisputable experimental evidence for the gluonic component of the η ′ . The decays D s → η/η ′ + ℓ + ν ℓ have been analysed before both phenomenologically, e.g., [13,14] and using leading order LCSRs with chiral currents including meson mass corrections [15]. We improved that LO twist-2 analysis by taking into account all two-particle twist-2 and twist-3 NLO quark contributions and in addition the NLO twist-2 gluon contribution.…”

Exclusive semileptonic decays of D and Ds mesons in the covariant confining quark model

“…Several D (s) semileptonic decay form factors have been calculated using QCD sum rules (QCDSR) [36][37][38][39] and QCD light-cone sum rules (LCSR) [40][41][42][43][44][45]. Most of these studies focused on the channels D → π(K) and D (s) → η (′) .…”

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

“…By using the obtained results and the result for f BK from [14] we obtain We can note that the approximation works quite well although somewhat better for M → η decays than for M → η transitions. There exists LCSR calculations of f + Dsη form factor [42,43]. In these papers the f + Dsη form factor is then obtained by using the relation…”