Differential cross sections and polarizations are presented for the reactions K − p → Λπ 0 , Λη , Λη ′ at 8.25 GeV/ c incident K − momentum. The data, which come from a high statistics experiment in the CERN 2 m bubble chamber, are compared with previous experimental results on the same reactions and with current theoretical ideas.
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Prompt dimuon production has been measured. Events with mass up to 25 GeV/c2 are observed, as well as the J and ϒ resonances. Cross sections are given for J and ϒ production. For the continuum, the scaling function F(τ) is measured at very small values of τ=ms covering the range 0.05<τ<0.20.
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HERE UPSILON = ALL USILON FAMILY. ANGULAR DISTBN. IS SEEN TO BE ISOTROPIC.
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DOMINANT NATURAL PARITY EXCHANGE.
EVIDENCE FOR FORWARD DIP FOR -TP < 0.1 GEV**2.
We observe production of a Ξ * (2370) in the reactions K − p→ [YK¯π] K, [YK¯π] Kπ and [ΩK] (K or Kπ) at 8.25 GeV/ c in a high statistics bubble chamber experiment. The mass and width are determined to be 2373 ± 8 MeV and 80 ± 25 MeV, respectively. The I = 1/2 assignment is strongly favoured.
CROSS SECTIONS FOR PRODUCTION OF XI(2370) --> (LAMBDA + SIGMA) AK PI. BREIT-WIGNER FIT WITH POLYNOMIAL BACKGROUND. XI(2370) PRODUCED BY BARYON EXCHANGE. CORRECTED FOR NEUTRAL DECAYS AND GEOMETRICAL LOSSES. <OMEGA-KAON> DECAY SEEN. OBSERVED RATIO OF CHARGED TO NEUTRAL XI(2370) PRODUCTION IS 2.7 +- 0.9.
We present evidence for a narrow Y ∗ with a mass of 3.17 GeV and a width ⩽ 20 MeV decaying to ΣKK̄ + pions, ΛKK̄ + pions and ΞK + pions. The data come from two high statistics K − p bubble chamber experiments with a sensitivity of ≈100 eV/ μb at 8.25 GeV/ c and ≈ 45 eV/ μb at 6.5 GeV/ c .
OBSERVATION OF R(3170) ONLY DECAYING INTO 5 OR 6 PARTICLES (CROSS SECTION NOT CORRECTED FOR DECAYS WITH MORE THAN ONE UNSEEN FINAL STATE PARTICLE).
Backward production of ω (1670) is observed in the reactions K − p→ φ + φ − ω 0 Λ 0 and K − p→ φ + φ − φ 0 φ 0 for | U ' Λ |<1.0 GeV 2 . The cross section for the ω (1670) → φ + φ − ω 0 decay mode is 1.90±0.35 μ b for 8.25 GeV/ c incident K − . Evidence is presented for the importance of the sequential decay, ω (1670) → B φ → ωφφ with a branching ratio ω (1670) → B φ /all ω (1670) → ωφφ =1.0± 0.25 0.00 .
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The energy dependence of the K L 0 -K S 0 transmission regeneration amplitudes on deuterons and neutrons in the momentum region 10–50 GeV/ c is determined. The moduli of the modified transmission amplitudes are momentum dependent. These dependences are fitted by the expression A j p − nj , where A j and n j ( j = d, n) are constants: A d =2.88 ±0.04 mb , n d =0.546±0.030, for deuterons , A n =1.97 ±0.14 mb , n n =0.530±0.019, for neutrons , The amplitude phases do not depend on the kaon momentum and are equal to ϕ d = (−130.9 ± 2.7)° ϕ n = (−132.3 ± 1.7)°. The mean value of the ratio of the total cross-section differences for K 0 and K 0 interactions with neutrons and protons is determined. The residues of the partial ω and ϱ amplitudes, which contribute to the kaon-nucleon interaction amplitudes, are also obtained.
FORWARD CROSS SECTION, AMPLITUDE AND PHASE FOR K0 REGENERATION.
(AK0 - K0) TOTAL CROSS SECTION DIFFERENCES.
Inclusive Λ production has been studied in K − p interactions at 8.25 GeV/ c using about 69 000 events; the total cross section is found to be 3.35 ± 0.20 mb. A comparison has been made with Σ 0 and Σ(1385) inclusive production. Their influence on the inclusive Λ production is discussed. The inclusive Λ cross section and polarization is interpreted in terms of the triple-Regge model. In the target fragmentation region an effective Regge trajectory is determined which lies closer to the K than to the K ∗ . In the beam fragmentation region the cross-section data indicate an effective Regge trajectory which corresponds to the nucleon, while the polarization data require additional Regge exchanges to be present.
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The production of strange particles in π + d interactions has been examined at 4 GeV/ c where no previous data exist. Careful attention has been given to the resolution of ambiguities and to corrections for losses in a total sample of about 22 000 events which have been used to determine channel cross sections. Where they can be checked, the cross sections fit well into the observed variation of existing cross sections at higher and at lower energies.
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