We present results on $\pi^+$-p interactions at 500 MeV from an experiment performed with the Saclay 35 cm hydrogen bubble chamber. A total of 1840 events have been observed. The branching ratio for elastic events is equal to 0.883$\pm$0.008. Eight events are unambiguously attributed to the reaction $\pi^+p\to\pi^+p\gamma$. Cross sections for the various reactions are given. The elastic angular distribution has been determined up to cos$\theta$ = +0.975 and shows evidence for S, P, D waves in good agreement with the results obtained in other experiments. For the one-pion production reactions, the ratio of $\pi^0$ production to $\pi^+$ production is found equal to 4.1$\pm$0.8. This result and the corresponding distributions for momentum and angle of the secondaries are compared with the predictions of the isobaric models.
No description provided.
The interactions of 720 MeV negative pions with protons were investigated using pictures from the 35 cm Saclay hydrogen bubble chamber. Partial cross-sections were determined with the following results: σ(elastic)=13.2±0.5) mb, σ(π−pπ0)=(5.25±0.30) mb, σ(π−π+n)=()7.17±0.35) mb σ (neutrals)=(9.9±0.7) mb, σ (2π production)=(1.03±0.13) mb. The elastic-scattering angular distribution was fitted with a fifth-order polynomial in cos θ* π which shows the effect of a significantF 5/2-D 5/2 interference contribution and predicts a value for (dσ/dΩ) (0°) in agreement with dispersion theory. For both single-π production channels, the two-body effective mass plots and c.m. angular distributions are presented, discussed and compared with the predictions from phase-space, the Olsson-Yodh isobar model and the pole model of isobar production. TheN *(3/2, 3/2) isobar is seen to play an important role in the ππN final states, but the agreement of the data with the existing isobar models and their assumptions is not satisfactory. A comparison of the different two-pion production cross-sections π−pπ−π+, π−pπ0π0 and π−π+nπ0 suggests a strong contribution of π−p→η0n to the π−π+nπ0 final state. An upper limit for σ(π−p→η0n) of (3.0±0.4) mb was obtained.
No description provided.
Results are presented onK+p elastic scattering and on the reactionK+p→K+pπ+π− at 70 GeV/c. For the
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INTEGRATION OVER RANGE OF ABS(T) FROM 0 TO 1 GEV.
ELASTIC DIFFERENTIAL CROSS SECTION AT T=0 DERIVED FROM THE OPTICAL THEOREM.
The ratio of the analysing powers for quasi-elastic pp scattering in carbon and for elastic scattering on free protons was measured fromT = 0.52 to 2.8 GeV by scattering of the SATURNE II polarized proton beam on carbon and CH2. It was found to have a maximum at about 0.8 GeV. The energy dependence for quasielastic scattering on carbon had not been measured before above 1 GeV. The observed effect was not expected from simple models.
No description provided.
The analyzing power A N of proton-proton, proton-hydrocarbon, and antiproton-hydrocarbon, scattering in the Coulomb-nuclear interference region has been measured using thhe 185 GeV/ c Fermilab polarized-proton and -antiproton beams. The results are found to be consistent with theoretical predictions within statistical uncertainties.
No description provided.
Angular distributions of the analyzing powers for π+p→ and π−p→ elastic scattering have been measured in a single-scattering experiment employing a polarized proton target. Measurements were obtained for pion energies of 98, 139, 166, 215, and 263 MeV. The addition of these data to the existing πp database significantly reduces the uncertainties in all S and P phase shifts for πp reactions over the delta resonance.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 98 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 139 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 166 MeV.
The analyzing power AN of proton-proton elastic scattering in the Coulomb-nuclear interference region has been measured using the 200-GeV/c Fermilab polarized proton beam. A theoretically predicted interference between the hadronic non-spin-flip amplitude and the electromagnetic spin-flip amplitude is shown for the first time to be present at high energies in the region of 1.5 × 10−3 to 5.0 × 10−2 (GeV/c)2 four-momentum transfer squared, and our results are analyzed in connection with theoretical calculations. In addition, the role of possible contributions of the hadronic spin-flip amplitude is discussed.
No description provided.
Analyzing powers for πp elastic scattering at bombarding energies below the Δ(1232) resonance were measured at TRIUMF using the CHAOS spectrometer and a polarized spin target. This work presents π− data at six incident energies of 57, 67, 87, 98, 117, and 139 MeV, and a single π+ data set at 139 MeV. The higher energy measurements cover an angular range of 72°<~θc.m.<~180° while the lower energies were limited to 101°<~θc.m.<~180°. There is a high degree of consistency between this work and the predictions of the VPI/GWU group’s SM95 partial wave analysis.
Analysing power measurements for a 139 GeV PI+ beam (standard track).
Analysing power measurements for a 139 GeV PI- beam (standard track).
Analysing power measurements for a 117 GeV PI- beam (standard track).
Analyzing powers for πp elastic scattering were measured using the CHAOS spectrometer at energies spanning the Δ(1232) resonance. This work presents π+ data at the pion kinetic energies 117, 130, 139, 155, 169, 180, 193, 218, 241, and 267 MeV and π− data at 87, 117, 193, and 241 MeV, covering an angular range of 50°<~θc.m.<~180° at the higher energies and 90°<~θc.m.<~180° at the lower energies. Unique features of the spectrometer acceptance were employed to reduce systematic errors. Single-energy phase shift analyses indicate the resulting S11 and S31 phases favor the results of the SM95 phase shift analysis over that of the older KH80 analysis.
Measurement of the PI+ analysing power at 117 MeV.. The data were collected in the conventional mode and may be independently floated within the systematic error.
Measurement of the PI+ analysing power at 139 MeV.. The data were collected in the conventional mode and may be independently floated within the systematic error.
Measurement of the PI- analysing power at 87 MeV.. The data were collected in the conventional mode and may be independently floated within the systematic error.
The reactions π − p → p π − and π − p → p ϱ − ( ϱ − → π − π 0 ) at 10 GeV/ c with the proton in the forward direction in the c.m.s. are discussed on the basis of 953 elastic scattering events and 2240 events of the reaction π − p → p π − π 0 . The total backward cross sections are 0.52±0.10 and 1.52±0.28 μ b, respectively. In both cases the production mechanism is compatible with the dominance of the baryonic Δ δ Regge trajectory exchange. The ϱ − decay angular distributions are studied in the u -channel helicity frame and the spin density matrix elements are presented as functions of u .
No description provided.
DATA FROM PRIV COMM WITH B. GHIDINI.
No description provided.
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