A study of the neutrinoproduction of Phi and D_s^+ mesons

The neutrinoproduction of $\phi$ and $D^+_s$ mesons is studied, using the data obtained with the SKAT bubble chamber at the Serpukhov accelerator. It is found that the $\phi$ production occurs predominantly in the forward hemisphere of the hadronic c.m.s. (at $x_F > 0$, $x_F$ being the Feynman variable), with the mean yield strongly exceeding the expected yield of directly produced $\phi$ mesons and varying from $<n_{\Phi}(x_F > 0) > = (0.92\pm0.34) \cdot 10^{-2}$ at $W >$ 2 GeV up to $(1.23\pm0.53) \cdot 10^{-2}$ at $W >$ 2.6 GeV and $(1.44\pm0.69) \cdot 10^{-2}$ at $W >$ 2.9 GeV, $W$ being the invariant mass of the hadronic system. The yield of leading $D^+_s$ mesons carrying more than $z = 0.85$ of the current $c$- quark energy is estimated: at $W > 2.9$ GeV, $<n_{D^+_s}(z > 0.85) > = (6.64\pm1.91) \cdot 10^{-2}$. It is shown, that the shape of the $\phi$ meson differential spectrum on $x_F$ is reproduced by that expected from the $D^+_s \to \phi X$ decays which, however, can account for only the half of the measured $\phi$ yield.