Gilbert Shapiro

SEARCH FOR T-VIOLATION IN THE INELASTIC SCATTERING OF ELECTRONS FROM A POLARIZED PROTON TARGET.

The authors have searched for an asymmetry in the inelastic scattering of electrons from a polarized proton target in the region of resonance excitation, at values of four-momentum transfer squared of 0.4, 0.6 and 1.0 (GeV/c){sup 2}. Data were also taken using an incident positron beam in order to distinguish any possible effect of time-reversal violation from that due to higher-order ({alpha}{sup 3}) contributions to the scattering. No sizeable violation of time-reversal invariance was found.

BACKWARD np SCATTERING WITH A POLARIZED TARGET.

The authors have measured the polarization parameter P in neutron-proton elastic scattering near the backward direction, using a polarized proton target. Measurements covered the range of incident neutron moment from 1.0 to 5.5 GeV/c and of four-momentum transfer squared u from -0.005 to -0.5 (GeV/c){sup 2}. Forward going protons were detected by means of a wire-spark-chamber spectrometer. Slow neutrons near 90 deg lab angle were detected in coincidence by means of an array of plastic scintillation counters. P was determined from the change in counting rate I of scattered particles upon reversal of the target polarization P{sub T} according to I = I{sub 0}[l + P(P{sub T} {center_dot} k incident neutron x k final neutron/sin {theta} final neutron)]. They find that P is consistently negative and shows no marked structure as a function of u and of incident momentum. The data roughly follow the simple form P = -0.5 {radical}-u/m{sub p}.

MEASUREMENT OF POLARIZATION IN pi- p ELASTIC SCATTERING FROM 229TO 3 90 MeV

The polarization parameter in elastic {pi}{sup -}p scattering has been measured, at the Berkeley 184 synchrocyclotron,l with the use of a polarized proton target. At 318, 337 and 390 Mev incident pion kinetic energy, the angular range from 70{sup o} to 180{sup o} in the center of mass system was covered. At 229 Mev polarization measurements were made in the angular range 150{sup o} to 180{sup o}. Phase shift analyses using these and other published data were made at the two lowest energies.