$D_s \rightarrow \eta, \eta'$ semileptonic decay form factors with disconnected quark loop contributions

Understand

We calculate for the first time the form factors of the semi-leptonic decays of the $D_s$ meson to $\eta$ and $\eta^\prime$ using lattice techniques.

• As a by-product of the calculation we obtain the masses and leading distribution amplitudes of the $\eta$ and $\eta^\prime$ mesons.
• We use $N_f=2+1$ non-perturbatively improved clover fermions on configurations with a lattice spacing $a\sim 0.075$ fm.
• We are able to obtain clear signals for relevant matrix elements, using several noise reduction techniques, both for the connected and disconnected contributions.