Lattice calculation of D_s → η(') semi-leptonic decay form factors

Issaku Kanamori (Regensburg)

We report lattice results of D_s meson semi-leptonic decay form factors to η and η' mesons.  Due to the mixing of η and η' these modes are relevant for flavor physics.  Our result is the first lattice calculation on these form factors.  The lattice calculation is challenging due to (computationally) expensive disconnected fermion loops.  These loops correspond to the weak annihilation diagram: D_s is annihilated by a weak current and η or η' is created out of gluons.  The result shows that the disconnected loops give significant contributions to the form factors, especially for D_s to η'.

(Seminarraum II)