Polarization measurements in high-energy deuteron photodisintegration
Abstract
We present measurements of the recoil proton polarization for the d(γ⃗,p⃗)n reaction at θ_(c.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 p_y vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer C_x 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.
Additional Information
© 2001 The American Physical Society. Received 15 September 2000; revised manuscript received 19 December 2000. We thank G. Farrar, N. Isgur, G.A. Miller, A. Radyushkin, J. Ralston, and M. Sargsian for many interesting discussions. We thank M. Sargsian for allowing us to mention his results prior to publication. We thank the JLab physics and accelerator divisions for their support, especially Ed Folts and the Hall A technical staff, and Charlie Sinclair and the polarized source group. This work was supported by the U.S. Department of Energy, the U.S. National Science Foundation, the Natural Sciences and Engineering Research Council of Canada, the French Commissariat à l'Energie Atomique and Centre National de la Recherche Scientifique, the Italian National Institute for Nuclear Physics, and the Swedish Natural Science Research Council. The Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility under DOE Contract No. DE-AC05-84ER40150. The polarimeter was funded by the U.S. National Science Foundation, Grants No. PHY 9213864 and No. PHY 9213869.Attached Files
Published - PhysRevLett.86.2975.pdf
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Additional details
- Eprint ID
- 41908
- Resolver ID
- CaltechAUTHORS:20131011-151242987
- Department of Energy (DOE)
- NSF
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Commissariat à l'Energie Atomique (CEA) (France)
- Centre National de la Recherche Scientifique (CNRS) (France)
- Italian National Institute for Nuclear Physics (INFN)
- Swedish Natural Science Research Council
- Department of Energy (DOE)
- DE-AC05-84ER40150
- NSF
- PHY-9213864
- NSF
- PHY-9213869
- Created
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2013-10-14Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field