Publication Title

Physical Review Letters

Publication Date

2001

Document Type

Article

DOI

10.1103/PhysRevLett.86.2975

Disciplines

Biochemistry, Biophysics, and Structural Biology

Abstract

We present measurements of the recoil proton polarization for thed(γ→,p→)nreaction atθc.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 polarizationpyvanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transferCxdoes not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in thed(γ,p)ncross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.

Comments

Copyright 2001, American Physical Society: http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.86.2975


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