Exclusive $D_s\to (\eta ,{\eta }^{\mathrm{\prime }})l\nu$ decays in light cone QCD

Probing the $\bar{s}s$ content of the $\eta$ and ${\eta }^{\mathrm{\prime }}$ mesons and considering mixing between these states as well as gluonic contributions, the form factors responsible for semileptonic $D_s\to (\eta ,{\eta }^{\mathrm{\prime }})l\nu$ 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.