None
No description provided.
No description provided.
No description provided.
We have measured elastic electron-proton scattering cross sections in the range of four-momentum transfers from 7 F−2[0.27 (GeV/c)2] to 150 F−2 [5.84 (GeV/c)2] and at scattered electron angles of between 20° and 34° in the laboratory. The estimated errors in the cross sections range from ±2.1% at the lowest momentum transfer to ±9.6% at the highest. Both the scattered electron and the recoil proton were detected, resulting in an overdetermination of the kinematics. When the constraint of a coincident proton is removed, there is no significant change in the estimated cross sections.
No description provided.
No description provided.
No description provided.
Differential cross sections for the reactions e−+p→e−+p+π0 and e−+p→e−+n+π+ have been measured near the Δ(1236) resonance at four-momentum transfers of 0.05, 0.13, 0.25, and 0.4 (GeV/c)2. A few measurements of the π+ angular distribution have been obtained at a four-momentum transfer of 0.6 (GeV/c)2. Cross sections for the π0 reaction are compared with dispersion-theory predictions at several pion-nucleon c.m. energies for each four-momentum transfer. A phenomenological analysis of the π0 results leads to the determination of the magnetic dipole and electric quadrupole partial-wave amplitudes and the γNΔ transition form factor. Evidence is found for the existence of a significant scaler-transverse interference term in the cross section, which is tentatively associated with the resonant scaler quadrupole interaction. Cross sections for π+ electroproduction are compared with dispersion theories using the pion form factor as a free parameter. The results suggest a form factor similar to that of the proton. A fit to the form-factor results, using the ρ-dominance model, requires mρ=560±80 MeV. The rms pion charge radius is estimated to be 〈r2〉12=0.86±0.14 F.
No description provided.
No description provided.
No description provided.
Elastic electron-proton scattering cross sections were measured at backward angles (80°-90°) in the laboratory for four-momentum transfers between 7 F−2 and 45 F−2. Experimental errors range from 3.1% to 5.3%, including a systematic error estimated to be 1.9% added in quadrature. Electric and magnetic form factors are computed from all the recent data in this q2 range, with allowance made for possible normalization differences. The results show a deviation from the scaling law.
No description provided.
No description provided.
No description provided.
The reaction e − + p → e − + p + π 0 has been studied in the region of the Δ (1236) resonance at a four-momentum transfer of the virtual photon of 0.3 (GeV/ c ) 2 . Angles and momenta of the secondary electron and of the outgoing proton were measured in coincidence to obtain the angular dependence of the differential cross section. The angular distribution for s- and p-waves of the pion in the πN cm-system was fitted to the cross section for three W -bins around the maximum of the resonance. The contribution of the resonant multipoles M 1+ , E 1+ and S 1+ to the cross section as well as the contribution of the background amplitudes M 1− , E 0+ and S 0+ are given.
No description provided.
No description provided.
No description provided.
Differential cross sections for the process γ p → p η have been measuredd at c.m. angles of 28°, 35° and 42° at incident energies between 2 GeV and 2.8 GeV. Data from an earlier experiment below 2 GeV have been re-analysed and corrected. The whole set of data is compared with the form ( s − M 2 ) 2 d σ /d t , which fits data at higher energies. There is good agreement above 2 GeV, particularly at the largest angle, but strong departures below.
No description provided.
THESE DATA ARE A REANALYSIS OF THOSE REPORTED IN P. S. L. BOOTH ET AL., NP B25, 510 (1971). THE CORRECTED RESULTS ARE IN GENERAL ABOUT TWICE THE OLD VALUES.
The reaction e − + p → e − + p + η has been studied in the region of the S 11 (1535)-resonance by detecting the recoil proton in coincidence with the scattered electron. The reaction has been observed at three four-momentum transfers of the virtual photon: q 2 = 0.2, 0.28 and 0.4 (GeV/ c ). First results of the differential cross section measurements are given and compared with quark model calculations.
No description provided.
No description provided.
We have measured the cross section, the distribution of scattering angles, and the distribution of noncoplanarity angles for electron-positron elastic scattering at 5 GeV c. m. energy. An analysis based on 230 events with scattering angles between 50 and 130° yields a ratio of the experimental to theoretical quantum-electrodynamic cross section of 1.03 ± 0.09. The scattering-angle and noncoplanarity-angle distributions are also found to be in excellent agreement with the quantum-electrodynamic predictions.
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.
We present data on K − p reactions leading to the final states K 0 n , π 0 Λ, ηΛ, η'Λ, π − Σ + , K 0 Δ 0 (1230), and π − Σ + (1385) from a bubble chamber experiment at 14.3 GeV/ c K − lab momentum. Total and differential cross sections, Λ and Σ ∓ polarisations in π 0 Λ and π − Σ + final states as well as the Σ + (1385) density matrix elements are given.
NORMALIZED TO A TOTAL CROSS SECTION OF 21.5 +- 0.2 MB (GALBRAITH ET AL, PR 138B, 913 (1965)).
No description provided.
No description provided.
Forum