Eur. Phys. J. C 25, 199-213 (2002)
DOI: 10.1007/s10052-002-0963-5

Scanning of the cross-section below 1 GeV by radiative events with untagged photon

V.A. Khoze^{1, 2}, M.I. Konchatnij³, N.P. Merenkov³, G. Pancheri⁴, L. Trentadue⁵ and O.N. Shekhovtzova<sup>5

1</sup>  Department of Physics and Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE, UK
²  Petersburg Nuclear Physics Institute, 188350 Gatchina, Russia
³  National Science Centre Kharkov Institute of Physics and Technology, 61108 Akademicheskaya 1, Kharkov, Ukraine
⁴  INFN Laboratori Nazionali di Frascati, P.O. Box 13, 00044 Frascati, Italy
⁵  Dipartimento di Fisica, Universita' di Parma and INFN, Gruppo Collegato di Parma, 43100 Parma, Italy

(Received: 4 February 2002 / Published online: 5 July 2002)

Abstract
We discuss an inclusive approach to the measurement of the cross-section by the radiative return method without photon tagging. The essential part of this approach is the choice of rules for event selection which provide rejection of events with 3 (or more) pions and decrease the final-state radiation background. The radiative corrections to the initial-state radiation process are computed for DA NE conditions, using the quasi-real electron approximation for both, the cross-section and the underlying kinematics. The two cases of restricted and unrestricted pion phase space are considered. Some numerical calculations illustrate our analytical results.

© Società Italiana di Fisica, Springer-Verlag 2002