Polarized Compton Scattering from the Proton

LEGS Collaboration; G. Blanpied; M. Blecher; A. Caracappa; C. Djalali; G. Giordano; K. Hicks; S. Hoblit; M. Khandaker; O. C. Kistner; G. Matone; L. Miceli; C. Molinari; B. Preedom; D. Rebreyend; A. M. Sandorfi; C. Schaerf; R. M. Sealock; H. Ströher; C. E. Thorn; S. T. Thornton; C. S. Whisnant; H. Zhang; X. Zhao

doi:10.1103/PhysRevLett.76.1023

Polarized Compton Scattering from the Proton

G. Blanpied, M. Blecher, A. Caracappa, C. Djalali, G. Giordano, K. Hicks, S. Hoblit, M. Khandaker, O. C. Kistner, G. Matone, L. Miceli, C. Molinari, B. Preedom, D. Rebreyend, A. M. Sandorfi, C. Schaerf, R. M. Sealock, H. Ströher, C. E. Thorn, S. T. Thornton, C. S. Whisnant, H. Zhang, and X. Zhao (LEGS Collaboration)

Phys. Rev. Lett. 76, 1023 – Published 12 February 1996

Abstract

New precision measurements of cross sections and polarization asymmetries in the $p (\vec{γ}, γ p)$ reaction at 90° c.m. are presented for incident energies between 213 and 333 MeV. A long-standing problem with earlier experiments that appeared to violate unitarity at the peak of the Δ is resolved. Data are compared to theories based on baryon resonance structure and to dispersion relations. Recent calculations using the proton polarizabilities are closest to the data, although inconsistencies are observed near the Δ resonance.

Received 25 August 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.1023

Authors & Affiliations

G. Blanpied⁴, M. Blecher⁶, A. Caracappa¹, C. Djalali⁴, G. Giordano², K. Hicks⁷, S. Hoblit^1,5, M. Khandaker^1,6, O. C. Kistner¹, G. Matone², L. Miceli^1,4, C. Molinari^1,9, B. Preedom⁴, D. Rebreyend⁴, A. M. Sandorfi¹, C. Schaerf³, R. M. Sealock⁵, H. Ströher⁸, C. E. Thorn¹, S. T. Thornton⁵, C. S. Whisnant⁴, H. Zhang⁷, and X. Zhao⁶ (LEGS Collaboration)

¹Physics Department, Brookhaven National Laboratory, Upton, New York 11973
²Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati, Frascati, Italy
³Università di Roma “Tor Vergata” and Istituto Nazionale di Fisica Nucleare-Sezione di Roma 2, Rome, Italy
⁴Department of Physics, University of South Carolina, Columbia, South Carolina 29208
⁵Department of Physics, University of Virginia, Charlottesville, Virginia 22901
⁶Physics Department, Virginia Polytechnic Institute & State University, Blacksburg, Virginia 24061
⁷Department of Physics, Ohio University, Athens, Ohio 45701
⁸II Physikalisches Institut, Universität Giessen, Giessen, Germany
⁹Università di Genova and Istituto Nazionale di Fisica Nucleare-Sezione di Genova, 16146 Genova, Italy