New CLEO II Results on Charm Hadron Decays

TL;DR

This paper reports new experimental measurements of charm hadron decay properties from the CLEO II experiment, including decay widths, branching fractions, evidence for specific decay modes, and form factor ratios, advancing understanding of charm quark dynamics.

Contribution

It provides the first measurement of the D*+ width, new branching fractions, evidence for Omega_c decays, and form factor ratios, offering novel data for charm hadron decay analysis.

Findings

D*+ width measured as 96 +- 4 +- 22 keV

Branching fractions for D+ semileptonic decays determined

Evidence found for Omega_c --> Omega- e+ nu_e decay

Abstract

We present new results on charm hadron decays from the CLEO II experiment. The D*+ width is measured for the first time, Gamma(D*+) = 96 +- 4 +- 22 keV. The semileptonic decay branching fractions are determined to be B(D+ --> Kbar*0 e+ nu_e) = (6.7 +- 0.4 +- 0.5 +- 0.4)% and B(D+ --> Kbar*0 mu+ nu_mu) = (6.5 +- 0.9 +- 0.5 +- 0.4)%. We observe evidence for Omega_c --> Omega- e+ nu_e and measure the product of the branching fraction and cross section, B(Omega_c --> Omega- e+ nu_e) x sigma(e+e- --> Omega_cX) = 42.2 +- 14.1 +- 11.9 fb. Within the framework of Heavy Quark Effective Theory, we measure in the decay Lambda+_c --> Lambda e+ nu_e the form factor ratio, R = f_2/f_1 = -0.31 +- 0.06 +- 0.06. This provides strong evidence that the form factor f_2 describing spin interactionof the s quark is non-zero. The Xi+_c lifetime is measured to be 503 +- 47 +- 18 fs. The results on branching fractions, cross section, and form factor ratio are preliminary.