S. Stein

Parity Non-Conservation in Inelastic Electron Scattering

Abstract We have measured parity violating asymmetries in the inelastic scattering of longitudinally polarized electrons from deuterium and hydrogen. For deuterium near Q2 = 1.6 (GeV/c)2 the asymmetry is (−9.5 × 10−5)Q2 with statistical and systematic uncertainties each about 10%.

Further measurements of parity non-conservation in inelastic electron scattering☆

Measurements of the y-dependence of the parity nonconserving asymmetries for inelastic electron scattering from deuterium. The measurements cover a range of y values from 0.15 to 0.36 and show only a small y-dependence. The results are in good agreement with the Weinberg-Salam model for sin/sup 2/theta/sub W/ = 0.224 +- 0.020. 20 references.

Observation of jet structure in high pT events at the ISR and the importance of parton transverse momentum

Abstract Events with a charged particle of high transverse momentum were studied in pp collisions at √s = 52.5 GeV with the Split Field magnet (SFM) at the CERN-ISR, triggering on a charged particle of pT > 2 GeV/c, in the c.m. angular region θ ≅ 20° and θ ≅ 45°. The results provide further evidence for jet-like structure in high pT reactions. One of two produced jets is associated with the triggering hadron whereas the other is produced at an azimuthal angle that differs from that of the trigger by roughly 180°. The main features of the data are found to agree with the predictions of a simple parton-parton hard scattering model with vector gluon exchange, provided that one allows for partons in the proton to have transverse momentum. The ingredients of the model are all derived from data on deep inelastic lepton-proton scattering and from hadron production in e+e− annihilation. The model retains a simple pT−4 dependence for the parton-parton scattering. However, for pT ≲ 4GeV/c, the transverse movement of partons yields an approximate pT−8 scaling for the inclusive hadron distribution in agreement with observations. For the understanding of our data, it is found to be essential to take into account the soft component arising from the fragmentation of the spectator partons into hadrons.

Inelastic electron scattering from hydrogen at 50° and 60°☆

Abstract Inelastic electron scattering cross sections have been measured for four-momentum transfers between 4.1 GeV 2 and 30.5 GeV 2 . At the large scattering angles of this experiment, the dominant contribution to the cross section comes from the W 1 structure function. In the conventional scaling variables, x and x ′, this structure function does not exhibit scaling behavior, and at fixed x or x ′ it is found to decrease with increasing four-momentum transfer.

Observation of leading particles in pp interactions with large transverse momentum secondaries at the CERN-ISR

Abstract Events with a positive particle of large transverse momentum emitted at medium angles have been studied using the split field magnet spectrometer at the CERN-ISR at a c.m. energy of √s = 52.5 GeV. Positive particles with large longitudinal momentum, |x| > 0.5, i.e., leading particles, associated to large pT events, are analysed.

Study of events with a positive particle of large transverse momentum emitted near the forward direction in pp collisions at √s = 52.5 GeV

Abstract The split field magnet facility of the CERN ISR has been used to measure events with a secondary particle of large transverse momentum. The selection was done by triggering on positive particles of p T > 1.5 GeV/ c emitted near the forward direction. Inclusive distributions of the other charged secondaries have been studied over almost the full kinematical range as a function of their y , p T , o and charge. The particle density shows a broad increase in the o hemisphere opposite to the selected large p T particle. This increase occurs in a wide rapidity interval centered at y = 0, although the trigger is at y = 2.

COINCIDENCE ELECTROPRODUCTION IN THE REGION OF THE rho MESON.

Cross sections for the reaction ep-+epX, measured by detecting both the scattered electron and proton, are given for missing masses mx between 0 and 1 GeV/c’. A large cross section is observed at mx=O due to radiative processes, but the resolution of the apparatus is such that the contribution of the mx=O peak is small for rnxL 0.6 GeV/c2. Enhancements rare observed in the region of the rho meson at q2=0. 1 and 0.5 (GeV/c)2. The electroproduction of all states with mx between 0.7 and 0.83 GeV/c2 varies like e -7.5t for q2=0.1 (GeV/c)2, similar to missing mass photoproduction in this region, but for q2=0. 5 (GeV/c)2 it varies like e -3.5t . (Submitted to Phys. Rev. Letters. A preliminary version of this paper was submitted to the 1971 International Symposium on Electron and Photon Interactions at High Energies, Cornell University, Ithaca, New York, August 23-27, 1971.) * Work supported by the U. S. Atomic Energy Commission t Present address: University of Washington, Seattle, Washington ItPresent address: Bonn University, Bonn, Germany This letter reports the results of an inelastic electron scattering experiment at SLAC where a final state proton was detected in coincidence with the scattered electron, ep + epX. The measured variables are Eo, the incident electron energy, E’, 0 , and @, the momentum, polar scattering angle, and azimuthal angle of the scattered electron; and P P’ BP and

Composition of particles emitted at large PT and medium angles in pp collisions at s = 52.5 GeV

P’ the corresponding proton variables. These measurements uniquely determine mx, the mass of the unobserved state X. rnE=2G Pp cos0 I It-l y p-s2-t(l+ v/‘Mp) where q2=4EoE1sin2(0/2)= -(four momentum transfer from the electron)2, 1, =EO-E’ , &I = v, d = an t 2MpTp= -(four momentum transfer to the proton)2. Tp is the kinetic energy of the proton,Mp is its mass, and 8 is the w angle between

Composition of Particle Emitted at Large p(T) and Medium Angles in p p Collisions at s**(1/2) = 52.5-GeV

andq. The cross section may be written’ d6, = r, d3”ab s dQdE’dtdmxdqq dtbxd9, where rT is the flux of virtual photons and Qq-is the azimuthal angle of 5 P around qwith respect to the electron scattering plane. d%abs/dtdmxd9, then represents the absorption of photons of mass q2 and energy v with a polarization parameter which is near unity for this experiment. During the experiment, E. and E1 were fixed at 20 and 13 GeV respectively. Two values of 8 were used, 1.124’ and 2. 51°, corresponding to q2=0. 1 and 0.5 (GeV/c)2. At each angle data were taken for values of t between 0.15 and

Charged hadron multiplicities and topologies in inelastic μ−p scattering☆

Abstract The relative yields of pions of both charges have been measured in the c.m angular 5.5° ⩽θ ∗ ⩽21° in collisions at s=52.5 GeV . The transverse momentum and x -dependence of these relative yields are presented and discussed.