Inclusive production of vector and tensor mesons is studied in a K − p experiment at 32 GeV/ c in the MIRABELLE bubble chamber. The K ∗ 0 (890) , ϱ 0 and ω cross sections are comparable, about 4 mb each. The K ∗ 0 (1420 and cross sections are also comparable, about 1 mb each. The K ∗ o ̈ + (890), Φ, K ∗ o ̈ − (1420) and f cross sections beam fragmentation; ϱ production is almost forward-backward symmetric in the c.m.s. The p T production slopes of K ∗ o ̈ − (890) and ϱ are similar, the Φ slope is shallower. Vector and tensor mesons alone are responsible for ≅50% (≅60%) of final-state pions
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We present results on a number of non-diffractive two-body channels contributing to reactions K + p→K 0 π + p and K + p→K + π − π + p. The data come from an exposure of the Mirabelle bubble chamber to an r.f. separated K + beam of 32 GeV/ c at the Serpukhov accelerator. Total cross sections are given for the final states K ∗+ (890) p , K ∗+ (1420) p , K 0 Δ ++ (1232), K ∗+ (890) p , Δ ++ (1232), K ∗0 (1420) Δ ++ (1232), K ∗0 (1780) Δ ++ (1232) and K ∗0 (890) Δ ++ (1950) . The differential cross sections are given for all channels with sufficient statistics. The energy dependence of the total and differential cross sections is studied.
FROM K0 P PI+ FINAL STATE.
DOUBLE RESONANCE CHANNEL CROSS SECTIONS CORRECTED FOR BACKGROUND, BREIT-WIGNER TAILS AND DIFFRACTIVE PROCESSES.
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We present experimental results on a number of K − p reactions at 14.3 GeV/ c that have three bodies in the final state. The final states are K − ω p , K − π p , Λπ + π − , Λ K + K − , Λp p , K ∗ − ω p , Λ(1520) K + K − and Λ(1520) p p . Whenever, with one exception explained by the Zweig rule, there is a K − or a proton in the final state, there is a diffractive-like threshold enhancement in the mass spectrum of the two recoiling particles. These enhancements account for a large fraction of the events in all but the Λπ + π − final state, where they cannot occur, and which is dominated by resonance production. We find evidence for the Q 1 (1300) decaying into K − ω .
THE DIFFRACTION DISSOCIATION CROSS SECTIONS ARE FOR DIFFRACTIVE THRESHOLD ENHANCEMENTS IN THE TWO-BODY MASS SPECTRA (WITHIN 500 MEV CM ENERGY OF THRESHOLD).
We discuss the structure of the momentum transfer distributions for the diffractive dissociation processes p → n π + , p → Δ ++ π − and K − → K 890 ∗0 π − . In the near-threshold mass region a clear break of slope is found around t ′KK ∼ 0.25 GeV 2 for the two baryonic channels, whereas no comparable structure is seen for the mesonic system. The K → K ∗ π differential cross section exhibits a nearly exponential behaviour up to t ′ pp ∼ 0.6 GeV 2 , falling over three orders of magnitude. The slope variations and breaks are strongly correlated both to the mass region considered and to the decay angle of the fragmentation system.
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We present experimental results and a partial-wave analysis of the low-mass ( K π) 0 systems produced in the reactions K − p → K π N at 14.3 GeV/ c . The main results concern the production mechanisms of the K ∗ (890) and K ∗ (1420) . We also extract the s-wave component of the K π system as a function of mass.
THE ERRORS QUOTED (EXCEPT FOR THE FIRST REACTION) ARE MAINLY AN ESTIMATE OF THE SYSTEMATIC UNCERTAINTIES.
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We present the first evidence for K ∗ (1780) production in a non-exchange channel. This comes from a study of the reaction K − p → K° π − p at 14.3 GeV/ c . We also present evidence for K ∗ ° (1780) production in the charge exchange channel K − p → K − π + n. No significant K ππ , K ω and K η decay modes are found. The decay angular distribution, the spin-parity assignments and the production mechanism are discussed. With plausible assumptions on the production mechanism, the J P = 3 − spin-parity is favoured.
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In a K − p experiment at 32 GeV/ c with a sensitivity of 6 ev/≈b the inclusive reaction K − p → p + X was studied in the kinematical region x < −0.3. Most of the protons in this region were identified by ionization. Correcting for losses of the very slow as well as of the fast protons in this region we obtained σ p ( x < −0.3) = 5.9 ± 0.2 mb. The double invariant differential cross sections of protons were analysed in terms of the variables x , p T 2 , and M 2 / s , t , and the contributions from separate peripheral mechanisms were analysed. A triple-Regge analysis was performed on the inclusive proton d 2 σ /d t d( M 2 / s ) distribution with | t | < 1.1 GeV 2 . The fit with an RRP term resulted in an effective trajectory for the exchanged reggeon lying somewhat lower than that for the leading meson trajectory. Inclusion in the fit of an additional ππp term showed that pion exchange is important in the triple-Regge region at small | t |.
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CROSS-OVER IS AT -T = 0.17 +- 0.02 GEV**2. DIVIDE BY 20 TO GET D(SIG)/DT IN MB/GEV**2. CORRECTED FOR LOST EVENTS FOR -T < 0.12 GEV**2.
FROM QUADRATIC EXPONENTIAL FIT TO D(SIG)/DT. BOTH STATISTICAL AND SYSTEMATIC ERRORS INCLUDED IN VALUES.
We have studied inclusiveΔ++ (1232),∑+ (1385), and∑− (1385) baryon resonance production inK−p interactions at 32 GeV/c. The inclusive and topological cross sections are estimated and compared with published results at lower energies. No energy variation of the cross section is observed forΔ++ (1232) and only a slight decrease is seen in case of∑± (1385). The production properties are investigated through longitudinal and transverse momentum distributions. TheΔ++ (1232) is dominantly produced in the target fragmentation region. The∑+ (1385) is produced both in the target fragmentation region and in the central region, while the∑− (1385) is predominantly produced in the central region. About 20% of the final state protons are produced via aΔ++ (1232) decay and about 25% of the Λ produced come from the decay of∑+ (1385) and∑− (1385).
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