Improved measurements of D meson semileptonic decays to pi and K mesons

TL;DR

This paper presents precise measurements of D meson semileptonic decay rates to pions and kaons, improving our understanding of these processes and extracting CKM matrix elements using experimental data and lattice QCD inputs.

Contribution

It provides improved branching fractions and form factor measurements for D meson semileptonic decays, and extracts |Vcd| and |Vcs| with reduced uncertainties.

Findings

Branching fractions for D decays are precisely measured.

Form factor shape parameters are determined using several models.

|Vcd| and |Vcs| are extracted with uncertainties including lattice QCD contributions.

Abstract

Using the entire CLEO-c \psi(3770)-> D\bar{D} event sample, corresponding to an integrated luminosity of $818 pb^-1 and approximately 5.4 million D\bar{D} events, we present a study of the decays D^0 -> \pi^- e^+ \nu_e, D^0 -> K^- e^+ \nu_e, D^+ -> \pi^0 e^+ \nu_e, and D^+ -> \bar{K}^0 e^+ \nu_e. Via a tagged analysis technique, in which one D is fully reconstructed in a hadronic mode, partial rates for semileptonic decays by the other D are measured in several q^2 bins. We fit these rates using several form factor parameterizations and report the results, including form factor shape parameters and the branching fractions B(D^0 -> \pi^- e^+ \nu_e) = (0.288\pm0.008\pm0.003)%, B(D^0 -> K^- e^+ \nu_e) = (3.50\pm0.03\pm0.04)%, B(D^+ -> \pi^0 e^+ \nu_e) = (0.405\pm0.016\pm0.009)%, and B(D^+ -> \bar{K}^0 e^+ \nu_e) = (8.83\pm0.10\pm0.20)%, where the first uncertainties are statistical and the second are systematic. Taking input from lattice quantum chromodynamics (LQCD), we also find |Vcd| = 0.234\pm0.007\pm0.002\pm0.025 and |Vcs| = 0.985\pm0.009\pm0.006\pm0.103, where the third uncertainties are from LQCD.