SLAC -PUB-412 May 1968 VECTOR DOMINANCE MODEL COMPARISON OF 7;t PHOTOPRODUCTION WITH p” PRODUCTION BY PIONS

Discrepancy between the Vector Dominance Model and Pion Production by Polarized Photons*

The helicity density matrix for the process 7r-p-T’P-n he1 has been studied as a function of MKT. The ratio p1 1 -I he1 pII shows no variation with Mnr and it thus seems unlikely that the large discrepancy between the vector dominance prediction and the observed asymmetry of single pions produced by linearly polarized photons could be the result of density-matrix distortion caused by background...

SLAC-PUB-431 June 1968 MEASUREMENTS OF 7r” and 77’ PHOTOPRODUCTION AT INCIDENT GAIXMA-RAY ENERGIES OF 5.0-17.8 GeV* bY

FORWARD PHOTOPRODUCTION OF VECTOR MESONS FROM HYDROGEN AT ENERGIES FROM 6.5 GeV TO 17.8 GeV*

We report measurements of the differential cross sections of P” and $ meson photoproduction on hydrogen for a range of fourmomentum transfer squared, t , from -0. 2(GeV/c)2 to -0. 9(GeV/c)2 and a range of incident photon energies from 6.5 GeV to 17.8 GeV. We find that differential cross sections obtained for p” production are in good agreement with the vector dominance model. * Work supported b...

Slfw-pub-527 November 1968. Cw Espe,rimental Inporn1ation on Teie 7i* Phoi'oproduc'1'ion Amplitudes "

Recent data on 7;* photoproduction at 3.4 GeV are used to investigate the nature of the amplitudes contributing to these processes. It is found that a large amplitude corresponding to natural-parity G = +I eschangs is necessary to exp1ai.n the data, even in the region t z-0.6 Ge-V2 where Reggeized p exchange must vanish. This implies a large contribution from some p' trajectory or from cnts, ab...

A COMPARISON OF n - p * P ” n WITH SINGLE PION PHOTOPRODUCTION AT 15 GeV

We present a comparison of new data on n-p -+ ,o”n at 15 GeV/c with polarized and unpolarized single pion photoproduction data. Particular emphasis is placed upon the behavior of the differential cross sections and asymmetries in the forward direction, (-t < m $ 0 (Submitted to Phys. Rev. Letters.) * Work supported by the U. S. Atomic Energy Commission. Studies of single pion photoproduction at...