The 1H(e,e'K+)Lambda reaction was studied as a function of the squared four-momentum transfer, Q2, and the virtual photon polarizations. The Q2 dependence of the sigma-L/sigma-T ratio differs ...significantly from current theoretical predictions. This, combined with the precision of the measurement, implies a need for revision of existing calculations.
The 3Lambda H and 4Lambda H hypernuclear bound states have been observed for the first time in kaon electroproduction on 3,4He targets. The production cross sections have been determined at Q**2= ...0.35 GeV**2 and W= 1.91 GeV. For either hypernucleus the nuclear form factor is determined by comparing the angular distribution of the 3,4He(e,e'K+)3,4Lambda H processes to the elementary cross section 1H(e,e'K+) Lambda on the free proton, measured during the same experiment.
Utilizing a next generation electron-positron collider of energy ge250 GeV, we describe how to produce copious hot photons of energy ge500 GeV. These hot photons can in turn scatter off nuclei and ...photoproduce bb and tausup +tausup minus pairs in a scheme called BACKGAMMON. Using a vertex detector, such a scheme would allow one to measure similar to10sup 9 bb and approx gt10sup 8 tausup +tausup minus pairs per year. Moreover, by employing polarized electron and laser beams, one could obtain polarized tau's, thus allowing one to directly study in a unique way the vector and axial-vector structure of tau decay.
Tensor polarization observables (t20, t21 and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c){sup 2}. The experiment ...was performed at the Jefferson Laboratory in Hall C using the electron HMS Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q{sup 2} the deuteron charge form factors G{sub C} and G{sub Q}. They are in good agreement with relativistic calculations and disagree with pQCD predictions.
Kaon electroproduction on deuterium Reinhold, J.; Abbott, D.; Ahmidouch, A. ...
Nuclear physics. A,
08/1998, Letnik:
639, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Kaon electroproduction on deuterium and hydrogen targets has been measured at beam energies of 3.245 and 2.445 GeV and momentum transfer Q
2 = 0.38 and 0.5 (GeV/c)
2. Associated Λ production off a ...proton in the deuteron exhibits a quasifree production mechanism. The electroproduction of a Σ
− off the neutron could be extracted for the first time with reasonable errors.
We report measurements of cross sections for the reaction p(e,e{prime}K{sup +})Y, for both the Lambda and Sigma{sub 0} hyperon states, at an invariant mass of W = 1.84 GeV and four-momentum transfers ...0.5 < Q{sup 2} < 2 (GeV/c){sup 2}. Data were taken for three values of virtual photon polarization, allowing the decomposition of the cross sections into longitudinal and transverse components. The Lambda data is a revised analysis of prior work, whereas the Sigma{sub 0} results have not been previously reported.
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