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We propose a precision measurement of the parity nonconserving left-right asymmetry in the scattering of longitudinally polarized electrons from the atomic electrons in a hydrogen target (MMller scattering) in End Station A. The asymmetry measures the eeective pseudo-scalar weak neutral current coupling governing MMller scattering (g ee g Ve g Ae) at an(More)
We present a Next-to-Leading order perturbative QCD analysis of world data on the spin dependent structure functions g p 1 , g n 1 , and g d 1 , including the new experimental information on the Q 2 dependence of g n 1. Careful attention is paid to the experimental and theoretical uncertainties. The data constrain the first moments of the polarized valence(More)
Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz in the three isospin channels gamma[over -->]p-->pi(+)pi(0)n, gamma[over -->]p-->pi(0)pi(0)p, and gamma[over -->]p-->pi(+)pi(-)p. The circularly polarized photons, produced from bremsstrahlung of longitudinally polarized electrons, were tagged with the Glasgow magnetic(More)
(2008). Measurement of the invariant-mass spectrum for the two photons from the η→π0γγ decay. Measurement of the invariant-mass spectrum for the two photons from the η → π 0 γ γ decay New results on the rare, doubly radiative decay η → π 0 γ γ have been obtained from a revised analysis of the Crystal Ball experiment performed at the AGS. The analysis yields(More)
We report on the first determination of upper limits on the branching ratio (BR) of eta decay to pi0pi0gamma and to pi0pi0pi0gamma. Both decay modes are strictly forbidden by charge conjugation (C) invariance. Using the Crystal Ball multiphoton detector, we obtained BR(eta-->pi0pi0gamma)<5 x 10(-4) at the 90% confidence level, in support of C invariance of(More)
We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25<E(m)<50 MeV and P(m) approximately 60 MeV/c, the reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly(More)
Information on the size and shape of the neutron skin on (208)Pb is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and(More)
We report on an investigation of the (pi(-),pi(0)pi(0)) reaction by means of measurements of the pi(0)pi(0) invariant mass distributions from pi(-) interactions on H, D, C, Al, and Cu targets at p(pi(-)) = 0.408 GeV/c. The sharp, strong peak in the pi(+)pi(-) invariant mass near 2m(pi) reported by the CHAOS Collaboration is not seen in our pi(0)pi(0) data.(More)
The double polarization observable E and the helicity dependent cross sections σ_{1/2} and σ_{3/2} were measured for η photoproduction from quasifree protons and neutrons. The circularly polarized tagged photon beam of the A2 experiment at the Mainz MAMI accelerator was used in combination with a longitudinally polarized deuterated butanol target. The(More)