Eur. Phys. J. A (2017) 53: 14
https://doi.org/10.1140/epja/i2017-12203-0

Regular Article - Experimental Physics

Determination of the scalar polarizabilities of the proton using beam asymmetry in Compton scattering

¹ Institut für Kernphysik, Universität Mainz, D-55099, Mainz, Germany
² Department of Physics, The George Washington University, 20052, Washington, DC, USA
³ School of Physics and Astronomy, University of Manchester, M13 9PL, Manchester, UK
⁴ Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, D-53115, Bonn, Germany
⁵ Department of Physics, Kent State University, 44242, Kent, OH, USA
⁶ SUPA School of Physics and Astronomy, University of Glasgow, G12 8QQ, Glasgow, UK
⁷ INFN Sezione di Pavia, I-27100, Pavia, Italy
⁸ Department of Physics and Atmospheric Science, Dalhousie University, B3H 4R2, Halifax, Nova Scotia, Canada
⁹ Department of Astronomy and Physics, Saint Mary’s University, B3H 3C3, Halifax, Nova Scotia, Canada
¹⁰ Departement Physik, Universität Basel, CH-4056, Basel, Switzerland
¹¹ School of Physics, University of Edinburgh, EH9 3JZ, Edinburgh, UK
¹² Institute for Nuclear Research, 125047, Moscow, Russia
¹³ Department of Physics, Mount Allison University, E4L 1E6, Sackville, New Brunswick, Canada
¹⁴ Department of Physics, University of Regina, S4S 0A2, Regina, Saskatchewan, Canada
¹⁵ Rudjer Boskovic Institute, HR-10000, Zagreb, Croatia
¹⁶ Institute for Theoretical and Experimental Physics, 117218, Moscow, Russia
¹⁷ National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Moscow, Russia
¹⁸ Lebedev Physical Institute, 119991, Moscow, Russia
¹⁹ Laboratory for Nuclear Science, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA
²⁰ Department of Physics, University of Massachusetts Amherst, 01003, Amherst, MA, USA
²¹ Department of Physics and Astronomy, University of California Los Angeles, 90095-1547, Los Angeles, CA, USA

^* e-mail: sokhoyan@uni-mainz.de

Received: 14 November 2016
Accepted: 4 January 2017
Published online: 25 January 2017

Abstract

The scalar dipole polarizabilities, and , are fundamental properties related to the internal dynamics of the nucleon. The currently accepted values of the proton polarizabilities were determined by fitting to unpolarized proton Compton scattering cross section data. The measurement of the beam asymmetry in a certain kinematical range provides an alternative approach to the extraction of the scalar polarizabilities. At the Mainz Microtron (MAMI) the beam asymmetry was measured for Compton scattering below pion photoproduction threshold for the first time. The results are compared with model calculations and the influence of the experimental data on the extraction of the scalar polarizabilities is determined.