Approximately 100 000 four-prong antiproton annihilations in hydrogen were measured. A clean, unbiased sample of 842 K + K − π + π − events was obtained. This reaction is dominated by K ∗ (∼45%) and ϱ 0 (∼20%) production, with smaller amounts of A 2 0 (∼15%) and ϕ (∼5%) production. 25% of the reactions involved double resonance production. No significant three-body resonance production is observed.
ERRORS INCLUDE SYSTEMATICS.
The cross sections for the reaction p¯+p→K++K−+π++π− were measured at six momenta from 400 to 670 MeV/c. Various effective mass distributions indicate that about 37% of the reaction involves K*0 or K¯*0, 16% proceeds via the intermediate state K*0+K¯*0, about 21% involves ρ, 5% proceeds via the ϕ+ρ state, and the rest follows phase space.
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Fraction obtained from the effective mass distribution.
Fraction obtained from the effective mass distribution.
Results are presented from a study of the annihilation interaction p―p→K+K−π+π− at 8.3 GeV/c based on data from an experiment performed with the large-aperture solenoid spectrometer (LASS) at the Stanford Linear Accelerator Center. A measurement of the reaction cross section is made, and contributions to the final state from the φ, f0A20, K*(890), K*(1430), and ρ0 resonances are studied.
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Results are presented from an experiment at the SLAC 40″ hybrid facility (SHF) using an 8.8 GeV/ c antiproton beam. Using external detectors and an on-line trigger, a sample of events enriched in p p annihilations was obtained. pp interactions taken under the same conditions enabled the annihilations to be identified. Cross sections and distributions for the inclusive production of K s 0 and K ∗± (890), and cross sections for exclusive channels with a pair of strange particles are presented.
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An analysis of a data sample of 1296 events of the reaction p p → K + K − π + π − at 2.32 GeV/ c is presented. The reaction cross section is 300 ± 20 μb . A number of tests of C conservation were made with careful attention to possible systematic errors, yielding no clear evidence of C violation. Various quasi two-body and quasi three-body final states contributing to this reaction were studied. The final state φπ + π − appears to be produced via a Zweig's rule violating mechanism. An analysis of the quasi three-body final state, K ∗0 K − π + (with K ∗0 → K + π − ) plus charge conjugate, whose cross section is 84 ± 12 μ b, is given. The properties of this final state are compared with expectations based on a simple baryon exchange model, and poor agreement is found. A quark model allows a successful qualitative interpretation of the properties of this three-body final state.
INCOHERENT BREIT-WIGNER PLUS PHASE SPACE FIT TO RESONANCE MASS SPECTRA. THE EQUAL CROSS SECTIONS FOR CHARGE CONJUGATE FINAL STATES ARE NOT TABULATED.
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