Eur. Phys. J. A 12, 125-127 (2001)

Measurement of G_Ep/G_Mp via polarization transfer at Q² = 0.4 GeV/c²

Th. Pospischil¹, P. Bartsch¹, D. Baumann¹, R. Böhm¹, K. Bohinc^{1, 2}, M. Ding¹, S. Derber¹, M.O. Distler¹, D. Elsner¹, I. Ewald¹, J. Friedrich¹, J.M. Friedrich¹, S. Grözinger¹, S. Hedicke¹, P. Jennewein¹, J. Jourdan³, M. Kahrau¹, F. Klein¹, K.W. Krygier¹, J. Lac⁴, A. Liesenfeld¹, S. Malov⁴, J. McIntyre⁴, H. Merkel¹, P. Merle¹, U. Müller¹, R. Neuhausen¹, M. Potokar², R.D. Ransome⁴, D. Rohe⁵, G. Rosner¹, J. Sanner¹, H. Schmieden¹, M. Seimetz¹, S. Sirca², I. Sick³, O. Strähle¹, A. Süle¹, A. Wagner¹, Th. Walcher¹ and M. Weis<sup>1

1</sup>  A1 Collaboration, Institut für Kernphysik, Universität Mainz, D-55099 Mainz, Germany
²  Institut Jozef Stefan, University of Ljubljana, SI-1001 Ljubljana, Slovenia
³  Departement für Physik und Astronomie, Universität Basel, CH-4056 Basel, Switzerland
⁴  Rutgers, The State University of New Jersey, Piscataway, New Jersey, USA
⁵  Institut für Physik, Universität Mainz, D-55099 Mainz, Germany

friedrch@kph.uni-mainz.de

(Received: 26 July 2001 / Revised version: 18 September 2001 Communicated by M. Garçon)

Abstract
The polarization transfer from longitudinally polarized electrons to protons in the elastic scattering has been measured around Q² = 0.4 (GeV/c)² with the three-spectrometer facility at the Mainz microtron MAMI. From this polarization transfer the ratio has been determined. The ratio is found to be slightly less than unity in agreement with recent results from other laboratories and from the Rosenbluth separation of cross-sections measured with unpolarized electrons.

PACS
25.30.Bf - Elastic electron scattering.
13.40.Gp - Electromagnetic form factors.
14.20.Dh - Protons and neutrons.
24.70.+s - Polarization phenomena in reactions.

© Società Italiana di Fisica, Springer-Verlag 2001