P. Avery et al., MEASUREMENT OF THE RATIOS OF FORM-FACTORS IN THE DECAY D(S)(-]PHI-E(+)NU(E)()), Physics letters. Section B, 337(3-4), 1994, pp. 405-410
The dynamics of the decay D(s)+ --> phie + nu(e) are studied using a s
ample of 474 events recorded by the CLEO II detector. A three dimensio
nal fit to the decay angles and q2 is performed to extract the ratios
of form factors R2 = A2(0)/A1(0) and R(v) = V(0)/A1(0), where A1(0) an
d A2(0) are the two axial vector form factors and V(0) is the vector f
orm factor evaluated at q2 = 0. By assuming the single pole parameteri
zation for the form factors, we obtain: R2 = 1.4 +/- 0.5 +/- 0.3 and R
(v) = 0.9 +/- 0.6 +/- 0.3.