David J Mack

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The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 μA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment,(More)
A separation of the longitudinal and transverse 12 C(e,eЈp) cross sections in the quasifree region has been performed in parallel kinematics at Q 2 of 0.64 and 1.8 GeV 2 for initial proton momentum Ͻ80 MeV. The separated transverse and longitudinal spectral functions at Q 2 ϭ0.64 GeV 2 show significant differences for missing energy between 25 and 60 MeV(More)
Video games have become both a widespread leisure activity and a substantial field of research. In a variety of tasks, video game players (VGPs) perform better than non-video game players (NVGPs). This difference is most likely explained by an alteration of the basic mechanisms underlying visuospatial attention. More specifically, the present study(More)
  • J Arrington, D F Spokesperson, K Geesaman, R Hafidi, D H Holt, P E Potterveld +42 others
  • 2006
Inclusive scattering from nuclei at x > 1 is sensitive to the distribution of high momentum nucleons at low Q 2 values, and high momentum quarks at large Q 2 values. Large x data at 4 and 6 GeV are dominated by quasielastic and resonance production from high-momentum nucleons. With the 11 GeV beam, we propose to make measurements in the DIS region and(More)
Separated longitudinal and transverse cross sections for charged pion electroproduction from (1)H, (2)H, and (3)He were measured at Q(2) = 0.4 (GeV/c)(2) for two values of the invariant mass, W = 1.15 GeV and W = 1.60 GeV, in a search for a mass dependence which would signal the effect of nuclear pions. This is the first such study that includes recoil(More)
The study of exclusive π(±) electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio RL=σL(π-)/σL(π+) is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from(More)
The charged pion form factor, F π (Q 2), is an important quantity that can be used to advance our knowledge of hadronic structure. However, the extraction of F π from data requires a model of the 1 H(e, e π +)n reaction and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from(More)
The 1H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F(pi)) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F(pi) is a free(More)
We have carried out an (e,e'p) experiment at high momentum transfer and in parallel kinematics to measure the strength of the nuclear spectral function S(k,E) at high nucleon momenta k and large removal energies E. This strength is related to the presence of short-range and tensor correlations, and was known hitherto only indirectly and with considerable(More)