Meson production in π−p and π+n interactions at 1.7 GeV/c has been studied in two bubble-chamber exposures. Combined results are presented with emphasis on single-pion production (4300 events) which is dominated by the formation of the ρ0 meson in peripheral interactions, and on double-pion production (1100 events) which shows strong formation of the ω meson. These data are compared with the predictions of particle-exchange models, including absorption, and the effects of competing channels are discussed. Evidence for a two-pion decay mode of the ω is examined quantitatively. Processes with higher meson multiplicities are described.
No description provided.
We have measured the antiproton-proton elastic differential cross section in the center-of-mass angular range cosθ=−0.985 to +0.40 at six momenta between 1.6 and 2.2 GeV/c in a bubble-chamber experiment. We use the data to look for evidence of direct-channel boson resonances.
No description provided.
Elastic π±−p, K−−p, and p¯−p scattering cross sections have been measured using three different experimental arrangements covering the c.m. angular regions ∼20°-120°, ∼135°-169°, and ∼165°-180° at incident momenta from 6 to 17 GeV/c. In the region 130°-180°, only π±−p scattering was measured. In the angular region near 180°, the energy dependences and shapes of the π−p backward peaks were determined up to crossed-momentum transfers of u∼−2 (GeV/c)2. At all energies, the π+−p backward peak had a sharp dip at u=−0.13 (GeV/c)2, with no similar effect in the π−−p case. Nearly complete angular distributions of π−−p elastic scattering from 20° to 180° have been obtained at 6 and 10 GeV/c. These results at 6 and 10 GeV/c as well as at 8 GeV/c reveal a sharp dip in π−−p scattering at t=−3 (GeV/c)2. Several structures in the form of dips or shoulders were seen in the p¯−p angular distributions also, with less pronounced structure observed in K−−p scattering. At fixed momentum transfer, all cross sections when expressed as dσdt appear to be decreasing with increasing energy.
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No description provided.
No description provided.
Approximately 700 events of the reaction K − d → K − π − pp s produced by 5.5 GeV/ c kaons were used to measure the cross section for Kπ elastic scattering in the T = 3 2 state by a Chew-Low extrapolation. The cross section does not exceed 2.1 mb and has no structure for Kπ masses from threshold up to 2.0 GeV.
Chew-Low extrapolation is used for evaluation of the K- P elastic cross section.
The elastic scattering of 3.6 GeV/ c π + mesons by protons has been studied in a hydrogen bubble chamber experiment. The elastic cross section has a measured value of 7.07 ± 0.20 mb. The forward diffraction peak has been fitted in the region 0.05 ≦ − t ≦ 0.6 (GeV/ c ) 2 by a form (d σ /d t ) = Ae Bt , where A = 46.5 ± 1.8 mb/(GeV/ c ) 2 and B = 6.85 ± 0.20 (GeV/ c ) −2 . From this fit and the optical theorem, the magnitude of the ratio of real to imaginary forward amplitude is 0.39 ± 0.06, in reasonable agreement with dispersion relation calculations and simple Regge model predictions.
No description provided.
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We have made measurements of polarization in π−p elastic scattering, with emphasis over the backward region, at 1.60 to 2.28 GeVc. The results indicate the absence of u-channel dominance in the backward region, as was observed in the case of π+p scattering. Comparisons have been made with predictions of various phase-shift analyses which show that the agreement is generally very poor in the backward region.
No description provided.
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No description provided.
A study of the A2+ mass spectrum in π+p interactions at 3.7 GeVc is presented. For a cut of t′=0.1−2.0 GeV2 and on eliminating the Δ++ we find that the three-pion mass spectrum in the A2+ region is fitted by the dipole formula with a confidence level of 53% and a single Breit-Wigner formula with a confidence level of 11%. Our result thus favors A2+ splitting although a single Breit-Wigner fit cannot be ruled out. We also report the A2+ decay branching fractions measured over all t′ values. They are 0.78 ± 0.05, 0.15 ± 0.04, 0.06 ± 0.03, and < 0.02 for ρπ, ηπ, KK¯, and η′π, respectively, in good agreement with other experiments.
No description provided.
The differential cross sections for π−p elastic scattering over the angular range 155° to 177° in the center of mass have been measured at 33 incident-pion momenta in the range 600 to 1280 MeV/c. Angular distributions are presented. The extrapolated differential cross sections at 180° show considerable structure, in particular a dip near 1150 MeV/c. In general the near-180° cross sections do not agree with existing phase shift solutions above 1000 MeV/c
INTERPOLATED DATA.
INTERPOLATED DATA.
INTERPOLATED DATA.
The polarization parameter in π + p backward elastic scattering at 6 GeV/ c incident pion momentum has been measured using a butanol polarized proton target, a high intensity pion beam, and a scintillation hodoscope detection system. Details of the apparatus and data analysis are presented here, together with the final results.
No description provided.
The reaction K − d → K − π + π − n p s was studied in a bubble chamber experiment. The cross section was measured to be 1.3 ± 0.2 mb. The final state is dominated by K ∗0 (890) , K ∗0 (1420) and Δ − (1236) production. Partial cross sections, differential cross sections and decay angular distributions of the K ∗0 (890) δ − (1236) final state were found to give good agreement with the predictions of Białas and Zalewski obtained from the quark model. The final state K − π + Δ − (1236) is analyzed by use of the Van Hove plot.
DEUTERIUM CROSS SECTIONS WITH SPECTATOR PROTON. PROBABLY NOT CORRECTED FOR K* BRANCHING RATIO INTO <K- PI+>.
SLOPE IS 5.75 +- 0.46 GEV**2 FOR -TP < 0.4 GEV**2.
GOTTFRIED-JACKSON FRAME.
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