We report on a study of the longitudinal to transverse cross section ratio, R={sigma}{sub L}/{sigma}{sub T}, at low values of x and Q{sup 2}, as determined from inclusive inelastic electron-hydrogen ...and electron-deuterium scattering data from Jefferson Laboratory Hall C spanning the four-momentum transfer range 0.06<Q{sup 2}<2.8 GeV{sup 2}. Even at the lowest values of Q{sup 2}, R remains nearly constant and does not disappear with decreasing Q{sup 2}, as might be expected. We find a nearly identical behavior for hydrogen and deuterium.
The {sup 1}H(e, e{sup '}{pi}{sup +})n cross section was measured for arange of four-momentum transfer up to Q{sup 2}=3.91 GeV{sup 2} at values of the invariant mass W above the resonance region. The ...Q{sup 2} dependence of the longitudinal component was found to be consistent with the Q{sup 2}-scaling prediction for hard exclusive processes. This suggests that the QCD factorization theorem is applicable at rather low values of Q{sup 2}. The transverse term falls off slower than the naive Q{sup -8} expectation and remains appreciable even at Q{sup 2}=3.91 GeV{sup 2}.
We report on precision measurements of the elastic cross section for electron-proton scattering performed in Hall C at Jefferson Lab. The measurements were made at 28 distinct kinematic settings ...covering a range in momentum transfer of 0.4<Q{sup 2}<5.5 (GeV/c){sup 2}. These measurements represent a significant contribution to the world's cross section data set in the Q{sup 2} range, where a large discrepancy currently exists between the ratio of electric to magnetic proton form factors extracted from previous cross section measurements and that recently measured via polarization transfer in Hall A at Jefferson Lab. This data set shows good agreement with previous cross section measurements, indicating that if a heretofore unknown systematic error does exist in the cross section measurements, then it is intrinsic to all such measurements.
We have measured the nuclear transparency of the A(e,e' pi^+) process in ^{2}H,^{12}C, ^{27}Al, ^{63}Cu and ^{197}Au targets. These measurements were performed at the Jefferson Laboratory over a four ...momentum transfer squared range Q^2 = 1.1 - 4.7 (GeV/c)^2. The nuclear transparency was extracted as the super-ratio of $(\sigma_A/\sigma_H)$ from data to a model of pion-electroproduction from nuclei without pi-N final state interactions. The Q^2 and atomic number dependence of the nuclear transparency both show deviations from traditional nuclear physics expectations, and are consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.
This investigation examines the way prime-time network television programming depicts physicians and the medical profession, and the influence of these images on public perceptions. The results ...indicate that network prime-time television programming portrays doctors, and people who watch more prime-time network programs featuring physicians perceive them, as more likely to be female and young, and as more imbued with interpersonal communication style, physical attractiveness, and power, but less imbued with the trait of character. The prospect that television depictions of physicians may undermine public confidence is explored.
The (3,4)(Lambda)H and (4)(Lambda)H hypernuclear bound states have been observed for the first time in kaon electroproduction on (3,4)He targets. The production cross sections have been determined at ...Q(2)=0.35 GeV2 and W=1.91 GeV. For either hypernucleus the nuclear form factor is determined by comparing the angular distribution of the (3,4)He(e,e(')K+)(3,4)(Lambda)H processes to the elementary cross section 1H(e,e K+)Lambda on the free proton, measured during the same experiment.
PDF
