Jefferson Lab Hall A
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Cross sections and Rosenbluth separations in 1H(e, e'K+)Lambda up to Q2=2.35 GeV2

The Jefferson Lab Hall A collaboration Coman, M. ; Markowitz, P. ; Aniol, K.A. ; et al.
Phys.Rev.C 81 (2010) 052201, 2010.
Inspire Record 837422 DOI 10.17182/hepdata.54197

The kaon electroproduction reaction 1H(e,e'K+)Lambda was studied as a function of the virtual-photon four-momentum, Q2, total energy, W, and momentum transfer, t, for different values of the virtual- photon polarization parameter. Data were taken at electron beam energies ranging from 3.40 to 5.75 GeV. The center of mass cross section was determined for 21 kinematics corresponding to Q2 of 1.90 and 2.35 GeV2 and the longitudinal, sigmaL, and transverse, sigmaT, cross sections were separated using the Rosenbluth technique at fixed W and t. The separated cross sections reveal a flat energy dependence at forward kaon angles not satisfactorily described by existing electroproduction models. Influence of the kaon pole on the cross sections was investigated by adopting an off-shell form factor in the Regge model which better describes the observed energy dependence of sigmaT and sigmaL.

11 data tables
Table 1

Measured values of the separated cross section at Q**2 = 2.35 GeV**2 and W = 1.85 GeV.. Errors contain both statistics and systematics.

Table 2

Measured values of the separated cross section at Q**2 = 1.90 GeV**2.. Errors contain both statistics and systematics.

Table 3

Measured values of the separated cross section at Q**2 = 2.35 GeV**2.. Errors contain both statistics and systematics.

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Cross section measurement of charged pion photoproduction from hydrogen and deuterium.

The Jefferson Lab Hall A collaboration Zhu, L.Y. ; Arrington, J. ; Averett, T. ; et al.
Phys.Rev.Lett. 91 (2003) 022003, 2003.
Inspire Record 601768 DOI 10.17182/hepdata.31722

We have measured the differential cross section for the gamma n --> pi- p and gamma p --> pi+ n reactions at center of mass angle of 90 degree in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at photon energies greater than 3.3 GeV exhibit a global scaling behavior for both pi- and pi+ photoproduction, consistent with the constituent counting rule and the existing pi+ photoproduction data. Possible oscillations around the scaling value are suggested by these new data The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi- to pi+ photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.

1 data table
Table 1

Differential cross section at THETA(CM) = 90 degrees.