Study of Semileptonic Charm Decays D^0 --> pi^- ell^+ nu and D^0 --> K^- ell^+ nu

TL;DR

This study measures the branching ratios and form factors of semileptonic D^0 decays to pions and kaons, providing insights into charm quark transitions and validating theoretical models with experimental data.

Contribution

It presents new measurements of decay ratios and form factors for D^0 --> pi^- l^+ nu and D^0 --> K^- l^+ nu decays using CLEO III data, enhancing understanding of charm semileptonic decays.

Findings

Measured R_0 = 0.082 ± 0.006 ± 0.005.

Determined form factor parameters for both decay modes.

Calculated ratio of form factor and CKM matrix elements as 0.038 +0.006-0.007 +0.005-0.003.

Abstract

We investigate the decays D^0 --> pi^- l^+ nu and D^0 --> K^- l^+ nu, where l = e or mu, using approximately 7 fb^{-1} of data collected with the CLEO III detector. We find R_0 = B(D->pienu)/B(D->Kenu) = 0.082 +- 0.006 +- 0.005. Fits to the kinematic distributions of the data provide parameters describing the form factor of each mode. Combining the form factor results and R_0 gives |f^pi_+(0)|^2 |V_{cd}|^2/|f^K_+(0)|^2 |V_{cs}|^2 = 0.038 +0.006- 0.007 +0.005-0.003.