Cross sections for ρ0 electroproduction measured in a streamer-chamber experiment are separated into elastic (ep→epρ0) and inelastic production channels. For the elastic channel, the total cross section and t dependence are presented. For the inelastic channel (1σ)dσdz, (1σ)dσdpT2, and a density matrix element are shown and compared to quark-parton-model predictions. The ratio of ρ0 to direct π0 production is found to be 2.0±0.5±0.3, where the first error is statistical, and the second error is systematic.
No description provided.
No description provided.
No description provided.
Results are presented on vector meson production in the hypercharge exchange reactions: π + p → K ∗+ (890) Y + and K − p→ ρ − Y + where Y + is either Σ + or Y ∗+ (1385). These reactions have been studied at 7 GeV/ c and 11.5 GeV/ c using the SLAC Hybrid Facility. Total and differential cross sections, hyperon polarization, and vector meson decay angular distributions are presented. We find that reactions with Σ + production are dominated by natural parity exchange. The Y ∗ (1385) reactions are consistent with substantial natural parity exchange contributions but also show significant unnatural parity exchange. The differential cross sections and polarization measurements for the vector meson production are compared to the pseudoscalar production reactions.
Axis error includes +- 20/20 contribution.
Axis error includes +- 20/20 contribution.
Axis error includes +- 20/20 contribution.
We present a systematic analysis of the production of K ∗+ (892) and Δ ++ (1236) resonances in the K + p → K 0 p π + reaction at 5, 8.25 and 16 GeV/ c . We have measured total cross sections, differential cross sections, density matrix elements and examined resonance production mechanisms in terms of the exchange of states with definite naturality. Some results on the reaction K + p → K ∗+ (1420) p are also given.
No description provided.
No description provided.
No description provided.
Cross sections, differential cross sections, and hyperon polarization results are presented for the reactions K¯0p→Λπ+ and K¯0p→Σ0π+ in the momentum interval 1 to 12 GeV/c. Emphasis is placed on the comparison of Λ and Σ channels, and on the momentum dependences of the data. In particular, the Λ polarization data are consistent with being independent of energy above 2 GeV/c; and the slopes of the forward cross sections are found to increase toward the slope values for the line-reversed reactions πp→K(Λ,Σ) as energy increases.
No description provided.
No description provided.
RESONANCE REGION CROSS SECTIONS.
A systematic analysis is presented on the reaction K + p → K ∗0 (890) Δ ++ for nine incident momenta between 4.6–16.0 GeV/ c . Cross sections, differential cross sections and vector meson single density matrix elements are given. As a function of energy, little if any change is observed in either the shapes of the differential cross sections or in the values of the density matrix elements. The data are interpreted in terms of current ideas on t -channel exchange mechanisms.
No description provided.
No description provided.
No description provided.
The differential cross sections for KL0p→KS0p scattering are presented in several momentum intervals between 1 and 10 GeVc. The data are strongly peaked in the forward direction, characteristic of a large s-channel helicity-nonflip scattering amplitude in this reaction, and a distinct break in the differential cross section occurs at |t|=0.3 GeV2. The phase of the forward scattering amplitude, φ, is consistent with being independent of momentum. The average value of the phase, φ=−133.9±4.0∘, corresponds to a Regge trajectory α(0)=0.49±0.05 in agreement with the canonical ρ, ω0 Regge intercept, α(0)∼0.5. However, this result disagrees with the Regge trajectory determined from the energy dependence of the forward cross section, α(0)=0.30±0.03, indicating a breaking of the Regge phase-energy relation. Comparisons of KL0p→KS0p and π−p→π0n scattering data reveal substantial differences in the energy dependence of the differential cross sections. Comparisons to KN charge-exchange data then suggest that direct-channel (absorption) effects may explain the differences in πN and KN channels.
No description provided.
No description provided.
No description provided.
We present results on vector-meson photoproduction via γp→Vp in the LBL-SLAC 82-in. hydrogen bubble chamber exposed to a linearly polarized photon beam at 2.8, 4.7, and 9.3 GeV. We find ρ0 production to have the characteristics of a diffractive process, i.e., a cross section decreasing slowly with energy and a differential cross section with slope of ∼ 6.5 GeV−2. Within errors the ρ0 production amplitudes are entirely due to natural-parity exchange. s-channel helicity is conserved to a high degree in the γ→ρ0 transition. We find evidence for small helicity-flip amplitudes for ππ pairs in the ρ0 region. Photoproduction of ω mesons is separated into its natural- (σN) and unnatural- (σU) parity-exchange contributions. The Eγ and t dependence and the spin density matrix of the unnatural-parity-exchange contribution are consistent with a one-pion-exchange process. The natural-parity-exchange part has characteristics similar to ρ0 production. At 9.3 GeV the ratio of σ(ρ0) to σN(ω) is ∼ 7. The slope of the φ differential cross section is ∼ 4.5 GeV−2, smaller than that of ρ0 and ω production. Natural-parity exchange is the main contributor to φ production. No evidence for higher-mass vector mesons is found in ππ, πππ, or KK¯ final states. The s and t dependences of Compton scattering as calculated from ρ, ω, and φ photoproduction using vector-meson dominance agree with experiment, but the predicted Compton cross section is too small by a factor of 2.
No description provided.
No description provided.
No description provided.
Total and differential cross sections are presented for the reaction KL 0p→KS 0p from 1.3 to 8.0 GeVc as measured in an exposure of the Stanford Linear Accelerator Center 40-in. hydrogen bubble chamber to a neutral beam. The forward points of dσ(KL 0p→KS 0p)dt together with K+n and K−n total cross sections are used to determine the intercept of the effective Regge trajectory, α(0)=0.47±0.09, and the regeneration phase ϕf=−43∘±8∘.
No description provided.
FULL T REGION.
FULL T REGION.
None
Only statistical errors are given.
Only statistical errors are given.
Forum