Abstract
Measurements of the and decay rates can be used to determine the magnitudes of the Cabibbo-Kobayashi-Maskawa matrix elements and , provided that the relevant hadronic form factors are known. Here we present a precise calculation of these form factors using lattice QCD with flavors of dynamical domain-wall fermions. The and quarks are implemented with relativistic heavy-quark actions, allowing us to work directly at the physical heavy-quark masses. The lattice computation is performed for six different pion masses and two different lattice spacings, using gauge-field configurations generated by the RBC and UKQCD Collaborations. The and currents are renormalized with a mostly nonperturbative method. We extrapolate the form factor results to the physical pion mass and the continuum limit, parametrizing the dependence using expansions. The form factors are presented in such a way as to enable the correlated propagation of both statistical and systematic uncertainties into derived quantities such as differential decay rates and asymmetries. Using these form factors, we present predictions for the and differential and integrated decay rates. Combined with experimental data, our results enable determinations of , , and with theory uncertainties of 4.4%, 2.2%, and 4.9%, respectively.
8 More- Received 25 March 2015
DOI:https://doi.org/10.1103/PhysRevD.92.034503
© 2015 American Physical Society