The real part of the forward amplitude for Compton scattering on protons was measured through the interference between the Compton and Bethe-Heithler amplitudes by detecting the zero-degree electron pairs asymmetrically. The measurement was made at an average photon energy of 〈k〉=2.2 GeV, and an average momentum transfer to the recoil proton 〈t〉=−0.027 (GeV/c)2. The result confirms the prediction of the Kramers-Kronig relation.
No description provided.
We have measured the polarization parameter in neuton-proton charge-exchange scattering for incident neutron momenta of 2-12 GeVc and 0.01<~|t|<~1.0 (GeVc)2. Results based on 300 000 events show a negative polarization whose magnitude increases monotonically with |t| approaching 60% for |t|∼0.6 and which has little energy dependence.
No description provided.
The reaction p ̄ p → n ̄ n has been studied at an incident antiproton laboratory momentum of 1.13 GeV/ c . The antineutron was identified through a subsequent annihilation on a proton. In all, 2601 identified events were obtained. Total and differential cross sections are presented. Comparison is made with the predictions of the Bryan and Phillips model which, in this energy range, is succesful in describing the related reaction p ̄ p → p ̄ p . Here, the agreement is less good.
No description provided.
Experimental results for the cross-sections, the effectivemass distributions, the angular distributions and correlations are presented for the reaction\(\bar p\)p → 3π−3π+. All the multipion mass distributions and the ππ angular correlations are described in terms of a final-state interaction model including theδ00 andδ11 ππ phase shifts, as well as an A2 effect.
No description provided.
INCOHERENT BRIET-WIGNER FIT TO 3PI- 3PI+ CHANNEL.
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.
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.
The final states øππ and øKK̄ arising from p̄p annihilations at 3.6 GeV/ c have been studied. The results are in agreement with Zweig's rule contrary to what is observed in high energy pp collisions.
No description provided.
Measurements of the polarised beam asymmetry parameter Σ for eta photoproduction from protons, have been carried out at incident energies of 2.5 GeV and 3.0 GeV, and for various t -values between −0.2 (GeV/c) 2 and −1.2 (GeV/c) 2 . The values of Σ are close to +1 for values of | t | less than 0.7 (GeV/c) 2 , showing that there can be little contribution from unnatural parity exchange in any Regge exchange model of the process, in disagreement with present theories. Differential cross sections for the process werre also measured, and are consistent with those from other experiments.
No description provided.
No description provided.
Antiproton-proton annihilations into final states containing one or two K10-mesons are studied on the basis of 450 000 pictures from the CERN 2 m HBC. The experiment covers the domain of antiproton incident momentum from 1.50 to 2.04 GeV/c. The resonance production rates are computed for the most abundant channels. The K10K10 threshold effect is explained through the inelastic channel π+π− → K10K10. The decay modes D, E → δ±(975)π∓, δ±(975) → K10K± are pointed out. The strange mesons C and C′ are observed in these annihilations and come mainly from the two-body channels \(p\bar p\) → (C, C′)K and\(p\bar p\) → (C, C′)K*.
RESONANCE FRACTIONS FOR AP P --> KS (K+ PI- + K- PI+).
RESONANCE FRACTIONS FOR AP P --> KS (K+ PI- + K- PI+) PI0.
RESONANCE FRACTIONS FOR AP P --> KS KS PI+ PI-.
We have measured the neutron-proton charge-exchange differential cross section in the momentum interval 60 to 300 GeV/c, with squared four-momentum transfers 0.002 to 0.8 (GeV/c)2. Independent of incident momentum, the data are characterized by a sharp forward peak of width 0.02 (GeV/c)2, followed by a shoulder and gentler falloff at higher momentum transfers.
No description provided.
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