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Item Cross-Section Measurement of Charged-Pion Photoproduction from Hydrogen and Deuterium(American Physical Society, 2003-06-11) Zhu, L.Y.; Arrington, J.; Averett, T.; Beise, E.; Calarco, J.; Chang, T.; Chen, J.P.; Chudakov, E.; Coman, M.; Clasie, B.; Crawford, C.; Dieterich, S.; Dohrmann, F.; Dutta, D.; Fissum, K.; Frullani, S.; Gao, H.; Gilman, R.; Glashausser, C.; Gomez, J.; Hafidi, K.; Hansen, J.-O.; Higinbotham, D.W.; Holt, R.J.; de Jager, C.W.; Jiang, X.; Kinney, E.; Kramer, K.; Kumbartzki, G.; LeRose, J.; Liyanage, N.; Mack, D.; Markowitz, P.; McCormick, K.; Meekins, D.; Meziani, Z.-E.; Michaels, R.; Mitchell, J.; Nanda, S.; Potterveld, D.; Ransome, R.; Reimer, P.E.; Reitz, B.; Saha, A.; Schulte, E.C.; Seely, J.; Sirca, S.; Strauch, S.; Sulkosky, V.; Vlahovic, B.; Weinstein, L.B.; Wijesooriya, K.; Williamson, C.F.; Wojtsekhowski, B.; Xiang, H.; Xiong, F.; Xu, W.; Zeng, J.; Zheng, X.; Jefferson Lab Hall A ColloborationWe have measured the differential cross section for the γn→π-p and γp→π+n reactions at θc.m.=90° in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at Eγ≳3.3 GeV exhibit a global scaling behavior for both π- and π+ photoproduction, consistent with the constituent counting rule and the existing π+ 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 π- to π+ photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.Item Exclusive Electron Scattering from Deuterium at High Momentum Transfer(American Physical Society, 1995-06-12) Bulten, H.J.; Anthony, P.L.; Arnold, R.G.; Arrington, J.; Beise, E.J.; Belz, E.; van Bibber, K.; Bosted, P.E.; van den Brand, J.F.J.; Chapman, M.S.; Coulter, K.P.; Dietrich, F.S.; Ent, R.; Epstein, M.; Filippone, B.W.; Gao, H.; Gearhart, R.A.; Geesaman, D.F.; Holt, R.J.; Jackson, H.E.; Jones, C.E.; Keppel, C.E.; Kinney, E.; Kuhn, S.E.; Lee, K.; Lorenzon, W.; Lung, A.; Makins, N.C.R.; Margaziotis, D.J.; McKeown, R.D.; Milner, R.G.; Mueller, B.; Napolitano, J.; Nelson, J.; O'Neill, T.G.; Papavassiliou, V.; Petratos, G.G.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; Tao, L.H.; White, J.L.; Zeidman, B.Cross sections are presented for the reaction 2H(e,e′p)n for momentum transfers in the range 1.2≤Q2≤6.8(GeV/c)2 and for missing momenta from 0 to 250 MeV/c. The longitudinal-transverse interference structure function has been separated at Q2 = 1.2(GeV/c)2. The observables are compared to calculations performed in nonrelativistic and relativistic frameworks. The data are best described by a fully relativistic calculation.