We present a study of the Cabibbo-allowed semimuonic decay modes of the DS+ produced in 600 GeV c π- -emulsion interactions. From a signal of 18.7±4.9-0.7+0.4 events in the DS+ → øμ+υ channel, the product of production cross section and partial width is measured with respect to that for D+ → K*0 μ+υ to be ( σ(DS+) σ(D+)). (Λ(DS+ → øμ+ν)Λ(D+ → K*0 μ+ν)) = 0.56 ± 0.14 ± 0.12. The form factor ratios in the decay, obtained by fitting to the decay angles and q2, are A2 (0) 1(0) = 2.1-0.5+0.6 ± 0.2 and V (0) A1 (0) = 2.3-0.9+1.1 ± 0.4, where A1 (0) and A2 (0) are the axial vector form factors and V(0) is the vector form factor, evaluated at q2 = 0. The first observation of DS+ → (ημ+υ + η'μ+υ) is also reported, and Γ (DS+ → (ημ+υ + η'μ+υ)) Γ (DS+ → øμ+υ) is determined to be 3.9 ± 1.6.
ASJC Scopus subject areas
- Nuclear and High Energy Physics