A study of the reaction e(+)e(-)->mu(+)mu(-)gamma(ISR) at LEP and search for new physics at annihilation energies near 80 GeV

A study of the channel e+e- → μ+μ-γISR, where γISR is an initial state radiation photon, is presented using data collected by the DELPHI experiment from 1991 to 1994. The total cross-section at effective annihilation energies (√s′) below the Z0 peak is obtained by using the events with relatively ha...

Full description

Bibliographic Details
Main Authors: Abreu, P, Adam, W, Adye, T, Ajinenko, I, Alekseev, G, Alemany, R, Allport, P, Almehed, S, Amaldi, U, Amato, S, Andersson, P, Andreazza, A, Antilogus, P, Apel, W, Asman, B, Augustin, J, Augustinus, A, Baillon, P, Bambade, P, Barao, F, Barbi, M, Barbiellini, G, Bardin, D, Barker, G, Baroncelli, A
Format: Journal article
Language:English
Published: 1997
Description
Summary:A study of the channel e+e- → μ+μ-γISR, where γISR is an initial state radiation photon, is presented using data collected by the DELPHI experiment from 1991 to 1994. The total cross-section at effective annihilation energies (√s′) below the Z0 peak is obtained by using the events with relatively hard initial state radiative photon(s) (Eγ > 1 GeV). The differential cross-section as a function of the muon polar production angle is also determined in order to extract the forward-backward asymmetries for the reaction e+e- → μ+μ- at energies √s′ between 20 and 87 GeV. The ratio of the helicity cross-sections σLL+σRR/σRL+σ LR, where the two subscripts stand for the helicities of the incoming e- and outgoing μ- respectively, is extracted from the differential cross-sections in order to test the Standard Model and to look for new physics near 80 GeV. No deviations from the Standard Model were found. © Springer-Verlag 1997.