The reaction π + p→ ωΔ ++ (1236) is studied at 16 GeV/ c . Cross section, differential cross section, single and joint spin-density matrix elements are given and the correlations between the ε and Δ ++ (1236) decay angular distributions are investigated. Natural and unnatural spin-parity exchanges contribute to this reaction in roughly equal amounts. Natural exchanges lead predominantly to Δ ++ (1236) with helicity ± 3 2 , while unnatural exchanges lead predominantly to Δ ++ (1236) with helicity ± 1 2 and to ε with helicity zero. Furthermore, unnatural exchanges are small at t ′≅0.2 GeV 2 compared to other t ′ values, which may be due to the nonsense wrong-signature-zero of the B-meson exchange. Quark model relations are found to be satisfied by the data.
CORRECTED FOR UNSEEN OMEGA DECAY MODES. 'SLICE METHOD' USED TO HANDLE RESONANCE TAILS AND BACKGROUND.
FROM EVENTS WITHIN MASS-CUTS FOR RESONANCES AND NORMALIZED TO TOTAL CROSS SECTION.
'ALL'.
A set of 43 momentum spectra from the inclusive reaction np→pX 0 was measured with good statistical accuracy at 1.39, 1.56, 1.73 and 1.90 GeV/ c (about 10 spectra per incident momentum), with a neutron beam obtained by stripping deuterons. The final proton was analysed in an angular region of between 0° and 20° in the laboratory by a magnetic spectrometer.
THE INDICATED POSSIBLE SYSTEMATIC ERROR ARISES FROM EXTRAPOLATION OF D(SIG)/DT TO THETA = 90 DEG.
No description provided.
The reaction π + p → ϱ 0 Δ ++ (1236) at 16 GeV/ c has been studied. Cross section, differential cross section, single and joint spin-density matrix elements are given. Correlations between the ϱ 0 and Δ ++ (1236) decay distributions are observed. Unnatural spin-parity exchanges, mainly observed at small t ' values, dominate the ϱ 0 Δ ++ (1236) production. The natural exchange contributions are only (7 ± 2)% and become as important as the unnatural exchanges beyond t ' = 0.3 GeV 2 . Contributions to Δ ++ (1236) helicity 3 2 states do not exceed 20% of the total ϱ 0 Δ ++ (1236) cross section and are mainly due to unnatural exchanges.
'SLICE METHOD' USED TO HANDLE RESONANCE TAILS AND BACKGROUND.
FROM EVENTS WITHIN MASS-CUTS FOR RESONANCES AND NORMALIZED TO TOTAL CROSS SECTION.
'B'.
In an experiment with the 1.5 m bubble chamber at the Rutherford Laboratory, the reaction K + d→K 0 pp has been studied at beam momenta of 2.2, 2.45 and 2.7 GeV/ c . The cross section for the reaction K + n→K 0 p has been estimated and found to be approximately twice that of the line-reversed reaction K − p → K 0 n at comparable energies. An SU(3) sum rule, due to Barger and Cline, has been tested and found not to be valid in this momentum range. The differential cross section for K + n→K 0 p has also been measured and a determination made of the imaginary to real ratio of the forward amplitude, using the optical theorem. Implications of these, and other results, for various Regge models are briefly discussed.
No description provided.
No description provided.
The α-proton elastic scattering has been measured with α particles at equivalent incident proton energies of 438, 648, and 1036 MeV. A structure is observed at the position where a second minimum is expected in the differential cross section. Comparison with improved versions of the Glauber model are presented.
X ERROR D(THETA) = 0.4400 DEG.
X ERROR D(THETA) = 0.2200 DEG.
X ERROR D(THETA) = 0.4400 DEG.
The reaction π − p → ω n has been studied at 8 and 12 GeV / c incident momenta with the CERN Omega spectrometer using a neutron time of flight trigger. The differential cross sections and the ω-decay density matrix elements are presented as functions of the momentum transfer squared − t in the range of 0.02 to 0.80 GeV 2 . The data are used to evaluate the intercept and slope of both the natural and unnatural parity exchange trajectories. Regge exchange amplitude factorisation tests involving the reaction π N → ω N are investigated.
No description provided.
'FIT'.
'FIT'.
Incident alphas on protons were used to measure the elastic cross section in the backward hemisphere at 3.20, 4.00, 5.08 and 6.00 GeV/ c . The level and shape of the angular distributions are strongly dependent on energy. A backward peak shows up at 4.00 GeV/ c and become much steeper when the energy increases.
X ERROR H = 0.50 G/CM**2. X ERROR D(THETA) = 0.8800 DEG.
X ERROR H = 0.50 G/CM**2. X ERROR D(THETA) = 0.4400 DEG.
X ERROR H = 0.50 G/CM**2. X ERROR D(THETA) = 0.8800 DEG.
We report results from a study of π−p→ω0n at 6.0 GeV/c based on 28 000 events from a charged and neutral spectrometer. Background under the ω0 is only 7%, a large improvement over deuterium-bubble-chamber work. Density matrix elements, projected cross sections, and effective trajectories for natural and unnatural exchanges are presented.
No description provided.
No description provided.
No description provided.
A 7.5 GeV linearly polarized photon beam was used to study ϱ 0 production on d, n and p in the SLAC 82 inch bubble chamber. The production of ϱ 0 is found to proceed mainly via t -channel natural parity exchange and to conserve s -channel c.m.s. helicity for small t . The I = 1 contribution to the γ N → ϱ 0 t -channel amplitude is found to be small at 7.5 GeV.
ERRORS QUOTED INCLUDE BOTH STATISTICAL AND SYSTEMATIC UNCERTAINTIES.
THE FOURTH REACTION IS THE SUM OF THE FIRST THREE, NAMELY THE CLOSURE DIFFERENTIAL CROSS SECTION.
DIPION EVENTS IN THE RHO0 MASS REGION (600 TO 880 MEV).
We have measured the differential cross section for π−p→η0n at 6.0 GeV/c from 6730 very clean events in which the decay η→π+π−π0 was detected. The high statistics reveals a sizable forward turnover, implying a dominance of the helicity-flip amplitude. A precisely determined A2 trajectory, linear for |t|<1.0 (GeV/c)2, is found from combining our data with those at energies up to 101 GeV.
THE RESOLUTION IN TP IS EVERYWHERE SMALLER THAN THE BIN WIDTH.
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