APS » PROLA » Phys. Rev. Lett. » Volume 86 » Issue 14

Phys. Rev. Lett. 86, 2975 - 2979 (2001)

Polarization Measurements in High-Energy Deuteron Photodisintegration
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K. Wijesooriya et al. (Jefferson Lab Hall A Collaboration)
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Received 15 September 2000; revised 19 December 2000

We present measurements of the recoil proton polarization for the d(γ→,p→)n reaction at θc.m.  =  90° 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 py 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(γ,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.


©2001 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v86/p2975
DOI: 10.1103/PhysRevLett.86.2975
PACS: 25.20.-x, 24.70.+s, 24.85.+p, 25.10.+s

* Present address: Argonne National Laboratory, Argonne, IL 60439.
† Corresponding author. Email address: gilman@jlab.org
‡
§ Present address: St. Mary's University, Halifax, Nova Scotia, Canada B3H 3C3.

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