Measurement of the ratio of the vector to pseudoscalar charm semileptonic decay rate Gamma(D+ ->(K)over-bar(*0)mu+v(mu))/Gamma(D+->(K)over-bar(0) (+)(mu)v(mu))

摘要

Using a high statistics sample of photo-produced charm particles from the FOCUS experiment at Fermilab, we report on the measurement of the ratio of semileptonic rates Gamma(D+ --> Kpimu(+)nu(mu))/Gamma(D+ --> K(0)mu(+)nu(mu)) = 0.625 +/- 0.045 +/- 0.034. Allowing for the Kpi S-wave interference measured in [J.M. Link, et al., FOCUS Collaboration, Phys. Lett. B 544 (2002) 89], we extract the vector to pseudoscalar ratio Gamma(D+ --> (K) over bar*(0)mu(+)nu(mu))/Gamma(D+ --> (K) over bar (0)mu(+)nu(mu)) = 0.594 +/- 0.043 +/- 0.033 and the ratio Gamma(D+ --> (K) over bar (0)mu(+)numu)/Gamma(D+ --> (K) over bar (-)pi(+)pi(+)) = 1.019 +/- 0.076 +/- 0.065. Our results show a lower ratio for F(D --> K* lv)/Gamma(D --> Klv) than has been reported recently and indicate the current world average branching fractions for the decays D+ --> (K) over bar (0)(mu(+), e(+))nu(mu,e) are low. Using the world average B(D+ --> K(-)pi(+)pi(+)) [K. Hagiwara, et al., Particle Data Group Collaboration, Phys. Rev. D 66 (2002) 010001, and 2003 partial update for edition 2004 (http://pdg.lbl.gov)] we extract B(D+ --> (K) over bar (0)mu(+)nu) = (9.27 +/- 0.69 +/- 0.59 +/- 0.61)%. (C) 2004 Elsevier B.V. All rights reserved.