Phi meson and accompanying strange particle production in 16 GeV/c π+p interactions. Final report

We have studied phi production in 16 GeV/c π+p interactions. K- identified in a Cherenkov counter were used to trigger the Stanford Linear Accelerator Center 2-meter streamer chamber. A sample of inclusive phi events was thus obtained where phi → K-K+. Information from a second Cherenkov counter was used to identify the K+ off-line. In addition, the visible decays in the streamer chamber of Λ0 → pπ- and K/sub s/0 → π+π- were used to obtain events of the type π+p → phi Λ0 + anything and π+p → phi K/sub s/0 + anything. With 1.26 x 109 π+ onto a 61 cm liquid hydrogen target, the experiment had a raw sensitivity of 3.1 events/nb. For the film measured so far, taking into account geometric acceptance, unseen decay modes, and all efficiency corrections, the sensitivities are 7.1 events/μb, 22 events/μb, and 27 events/μb respectively for the phi inclusive, phi with Λ0, and phi with K/sub x/0 samples. The acceptance covers the region in Feynman's x, x/sub phi/ > 0.5. The measured cross sections for x/sub phi > 0.5 are sigma(phi + chi) = 1.3 +- 2.0 μb, sigma(phi Λ0 + chi) = 0.37 +- 0.16 μb, and sigma(phi K/sub s/0 + chi) = 0.33 +- 0.15 μb. When account is taken of unseen associated channels, it is concluded that phi is predominantly produced conjointly with pairs of strange particles. This agrees with the OZI rule, and is consistent with phi being produced by a quark fusion type process, rather than gluon fusion or light quark annihilation. 43 references