Polarization measurements in high-energy deuteron photodisintegration.
We present measurements of the recoil proton polarization for the d(gamma-->,p-->)n reaction at straight theta(c.m.) = 90 degrees for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization p(y) vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(gamma,p)n cross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.
Wijesooriya, K; Afanasev, A; Amarian, M; Aniol, K; Becher, S; Benslama, K; Bimbot, L; Bosted, P; Brash, E; Calarco, J; Chai, Z; Chang, CC; Chang, T; Chen, JP; Choi, S; Chudakov, E; Churchwell, S; Crovelli, D; Dieterich, S; Dumalski, S; Dutta, D; Epstein, M; Fissum, K; Fox, B; Frullani, S; Gao, H; Gao, J; Garibaldi, F; Gayou, O; Gilman, R; Glamazdin, S; Glashausser, C; Gomez, J; Gorbenko, V; Hansen, O; Holt, RJ; Hovdebo, J; Huber, GM; de Jager, CW; Jiang, X; Jones, C; Jones, MK; Kelly, J; Kinney, E; Kooijman, E; Kumbartzki, G; Kuss, M; LeRose, J; Liang, M; Lindgren, R; Liyanage, N; Malov, S; Margaziotis, DJ; Markowitz, P; McCormick, K; Meekins, D; Meziani, ZE; Michaels, R; Mitchell, J; Morand, L; Perdrisat, CF; Pomatsalyuk, R; Punjabi, V; Ransome, RD; Roche, R; Rvachev, M; Saha, A; Sarty, A; Schulte, EC; Simon, D; Strauch, S; Suleiman, R; Todor, L; Ulmer, PE; Urciuoli, GM; Wojtsekhowski, B; Xiong, F; Xu, W; Jefferson Lab Hall A Collaboration,
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