H. DeStaebler

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.

Measurement of the ratio of the proton form factors, GE/GM, at high momentum transfers and the question of scaling☆

Abstract Electron-proton elastic scattering cross sections have been measured at the Stanford Linear Accelerator Center at four-momentum transfers squared (q2) of 1.0, 1.5, 2.0, 2.5and 3.75 (GeV/c)2. The angular distributions at q2 = 2.5 and 3.75 (GeV/c)2are sufficient to provide values of the ratio GE/GMindependent of the results from other laboratories. Our results are compatible with scaling, GE(q2) = GM(q2)/μ, within the experimental errors.

Determination of ±s from a differential-jet-multiplicity distribution in e+e- collisions at ss =29 and 91 GeV

We measured the differential jet-multiplicity distribution in {ital e}{sup +}{ital e}{sup {minus}} annihilation with the Mark II detector. This distribution is compared with the second-order QCD prediction and {alpha}{sub {ital s}} is determined to be 0.123{plus minus}0.009{plus minus}0.005 at {radical}{ital s}{approx}{ital M}{sub {ital Z}} (at the SLAC Linear Collider) and 0.149{plus minus}0.002{plus minus}0.007 at {radical}{ital s}=29 GeV (at the SLAC storage ring PEP). The running of {alpha}{sub {ital s}} between these two center-of-mass energies is consistent with the QCD prediction.

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.

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

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

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

Background measurements during PEP-II commissioning

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

A sandwich structure beam pipe for storage rings

Abstract We report the final state charged-hadron multiplicities and topological cross sections for inelastic scattering of 16 GeV μ −, s from hydrogen in the SLAC 40-inch bubble chamber. We find that for 1.8 ⩽ W ⩽ 5.0 GeV the charged hadron multiplicity is generally lower at Q 2 = 1.5 GeV 2 than for photoproduction.

Determination of. alpha. sub s from a differential-jet-multiplicity distribution in e sup + e sup minus collisions at radical s =29 and 91 GeV

A variety of background detectors were installed at the interaction point of PEP-II for measurements of machine backgrounds during commissioning. Results from these detectors, machine experiments, and simulations have been used to reduce the backgrounds at PEP-II before the installation of the BaBar physics detector.