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).
Significant production of (2030) is observed in the channel K − p → (Σ K − K + from a high statistics bubble chamber exposure at 4.2 GeV/ c . The mass and width are determined to be 2024 ± 2 MeV and 16 ± 5 MeV respectively. Apart from Σ K , the only other decay channel is found to be Λ K .
ASSUMING XI(2030) HAS ISOSPIN HALF, CROSS SECTIONS CORRECTED FOR UNOBSERVED NEUTRAL DECAYS.
In π − p interactions at 9 GeV/ c and 12 GeV/ c , the forward production of N ∗ 1680 and N ∗ 1520 has been observed with features of nucleon exchange. The production of Δ1232 is strongly suppressed.
No description provided.
SLOPE ABOUT 6 GEV**-2 FOR SMALL U AND EVIDENCE FOR CHANGE OF SLOPE NEAR -U = 0.15 GEV**2.
From the study of the reaction π − p→p F p p π − using a fast proton (p F ) trigger device in the CERN Omega spectrometer, we find evidence for two narrow p p states produced mainly in association with a Δ° (1232) and a N° (1520). The statistical significance of each peak is greater than 6 standard deviations. Masses and natural widths of these resonances are respectively M = 2020 ± 3 MeV , Λ 1 = 24 ± 12 MeV and M 2 = 2204 ± 5 MeV, Λ 2 = 16 −16 +20 MeV. Our data are consistent with a small production of the narrow ∼ 1935 MeV resonance already reported. Production cross sections for these new p p resonances are given.
ERRORS TAKE INTO ACCOUNT STATISTICAL ERRORS AND BACKGROUND SUBTRACTION UNCERTAINTY BUT NOT ACCEPTANCE CORRECTIONS UNCERTAINTY OF 15 PCT.
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 measured the cross section for proton-proton elastic scattering at 11.75 GeV/c using the Zero Gradient Synchrotron 52% polarized proton beam and a 60% polarized proton target. We measured dσdt(ij) in the ↑↑, ↓↓, and ↑↓ initial spin states perpendicular to the scattering plane in the range P⊥2=2.0−3.6 (GeV/c)2. We found that the asymmetry parameter A decreases smoothly with increasing P⊥2 in this range, and that the spin-spin correlation parameter Cnn may have a minimum near P⊥2=3 (GeV/c)2.
No description provided.
We report on inclusive production of J ψ (3.1)-mesons observed in e + e − -annihilation in the energy range s = 4.0–5.0 GeV . After substraction of the radiative tail of the ψ(3.7) direct production of the J ψ (3.1) is found to be in the order of 0.1% of the total hadronic cross section. No enhancements are seen at s = 4.03 GeV and 4.4 GeV. The level is in agreement with expectations from violation of the Zweig-rule.
THIS IS 0.13 PCT OF THE TOTAL HADRONIC CROSS SECTION.
The Split Field Magnet facility at the CERN ISR has been used to measure inclusive resonance production in inelastic p-p collisions at a c.m. energy of 53 GeV. The mass spectrum of pairs of oppositely charged hadrons shows a strong correlation, which can be explained as a consequence of dominant vector meson production, accounting for more than 60% of all pions and kaons produced.
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A measurement of the coherent regeneration amplitude in carbon in the energy range 30-130 GeV is presented. The results are consistent with the dominance of this process by ω exchange, and a precise value of the intercept of the ω trajectory is obtained: αω(0)=0.390±0.014.
No description provided.
A partial-wave analysis of the (3 π ) 0 system produced peripherally in the reaction K − p → π + π − π 0 Λ at 4.2 GeV/ c is presented. The observation of the weak Λ decay allows a determination of all the transversity production amplitudes except for two phases. The production of known resonances having decay modes other than 3 π is used to test the isobar model ansatz. Significant ω(783), φ(1020) and A 2 (1310) production is observed. The spin parity of the ω ∗ (1675) is established as 3 − . No evidence for production of other resonances, such as axial vector-mesons, is found.
No description provided.
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