Measurement of the ratios of form factors in the decay Ds+ → φe+ve☆

Abstract The dynamics of the decay D s + → φe + v e are studied using a sample of 474 events recorded by the CLEO II detector. A three dimensional fit to the decay angles and q 2 is performed to extract the ratios of form factors R 2 = A 2 (0)/ A 1 (0) and R v = V (0 )/ A 1 (0), where A 1 (0) and A 2 (0) are the two axial vector form factors and V (0) is the vector form factor evaluated at q 2 =0. By assuming the single pole parameterization for the form factors, we obtain: R 2 =1.4±0.5±0.3 and R v =0.9±0.6±0.3.