$D\to Kl\nu$ semileptonic decay using lattice QCD with HISQ at physical pion masses

Abstract

The quark flavor sector of the Standard Model is a fertile ground to look for new physics effects through a unitarity test of the Cabbibo-Kobayashi-Maskawa (CKM) matrix. We present a lattice QCD calculation of the scalar and the vector form factors (over a large $q^2$ region including $q^2=0$) associated with the $D\to Kl\nu$ semi-leptonic decay. This calculation will then allow us to determine the central CKM matrix element, $V_{cs}$ in the Standard Model, by comparing the lattice QCD results for the form factors and the experimental decay rate. This form factor calculation has been performed on the $N_f=2+1+1$ MILC HISQ ensembles with the physical light quark masses.

Comments: Proceedings for the 35th International Symposium on Lattice Field Theory (Lattice 2017), 8 pages, 5 figures