Total and differential cross sections are presented for the reactions K − p → K − p and K − p → K o n at 13 points in the c.m. energy range 1915–2168 MeV. An energy-dependent partial-wave analysis is carried out on these data together with the polarisation measurements of Daum et al. [1] and the total cross section measurements [2] within this energy range. The well known Σ(1915), Σ(2030) and Λ(2100) are observed and their resonance parameters measured. Structure is also found in the D 05 and F 07 waves. An SU(3) analysis of the 5 2 + octet, 7 2 + decuplet and 7 2 − singlet gives generally good agreement between theory and experiment except that the elasticity of the Σ(1915) is experimentally rather larger than predicted.
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DETERMINED BY NORMALIZING AT ZERO DEG TO TOTAL CROSS SECTIONS VIA THE OPTICAL THEOREM.
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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.
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We studied 21 187 two-prong, two-prong-with-kink, and zero-prong-V events at incident kaon momentum of 1.33 GeVc using the 72-in. hydrogen bubble chamber at the Lawrence Radiation Laboratory and two scanning and measuring projectors in Urbana. We determined the total and partial cross sections for all contributing reactions. For the two-body final states, some production and polarization angular distributions were measured. The angular distributions are discussed in terms of exchanges in the kinematical channels s, t, and u assuming the simplest Feynman graphs. Elastic scattering is analyzed as a diffraction process.
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Elastic electron-proton scattering cross sections have been measured using the internal beam of the 6-BeV Cambridge Electron Accelerator at laboratory scattering angles between 31° and 90° for values of the four-momentum transfer squared ranging from q2=0.389 to 6.81 (BeV/c)2 (q2=10 to 175F−2). Incident electron energies ranged from 1.0 to 6.0 BeV. Scattered electrons from an internal liquid-hydrogen target were momentum-analyzed using a single quadrupole spectrometer capable of momentum analysis up to 3.0 BeV/c. Čerenkov and shower counters were used to help reject pion and low-energy background. The cross sections presented are absolute cross sections with experimental errors ranging from 6.8% to 20%. Separation of proton electromagnetic form factors have been made for all but the two highest momentum transfer points, using the Rosenbluth formula. Both form factors, GEp and GMp, were observed to continue to decrease as the momentum transfer increases. An upper limit to the possible asymptotic values of the proton electromagnetic form factors has been established.
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Measurements have been made of the ratio of the π+ photoproduction cross sections at right angles to and along the electric field vector. Data have been taken at 45°, 90°, and 135° at energies of 227, 240, 342, and 373 MeV. A comparison of the data with the predictions of a phenomenological analysis using only S and P waves shows less than 0.1% chance of obtaining such results without the inclusion of higher angular momenta, and hence, demonstrates even more convincingly the need for a meson current term which has been indicated by other measurements. A comparison is made with the relativistic dispersion relations of McKinley which include an approximation for the γ, ρ, π coupling. At the resonance energy our polarization asymmetry is insensitive to this coupling and is in good agreement with the McKinley prediction. At lower energy the agreement is not as good but our data seem to substantiate the need for a negative γ, ρ, π coupling constant.
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The polarization of the proton from the γ+n→p+π− reaction in deuterium has been experimentally measured at 90° in the center-of-mass system for photon energies near 715 MeV by using a counter technique to observe the left to right asymmetry in the scattering of the protons from carbon. A value of -0.26±0.06 was observed, with the direction of the polarization defined by n^=(k^×q^)|k^×q^|, where k^ and q^ are, respectively, unit vectors in the directions of the photon momentum and the pion momentum. The result is interpreted as an indication that the interference between the P32 (325 MeV) and D32 (750 MeV) resonances may not be the dominant contribution to the polarization at this energy. Significant contributions from either an interference between the P32 (325 MeV) resonance and the possible new resonance suggested by the π, p scattering measurements, or an interference between the D32 (750 MeV) and F52 (1050 MeV) resonances, or a combination of these two possibilities seem to be required.
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