Photon radiation in $$e^+e^-\;\rightarrow \;$$ e + e - → hadrons at low energies with carlomat_3.1

Abstract

Abstract We present a sample of results for the cross sections of several processes of low energetic $$e^+e^-$$ e + e - annihilation into final states containing pions accompanied by one or two photons, or a light lepton pair. The results, which have been obtained with a new version of a multipurpose Monte Carlo program carlomat, labelled 3.1, demonstrate new capabilities of the program which, among others, include a possibility of taking into account either the initial or final state radiation separately, or both at a time, and a possibility of inclusion of the electromagnetic charged pion form factor for processes with charged pion pairs. We also discuss some problems related to the U(1) electromagnetic gauge invariance.

Keywords

• Form Factor
• Monte Carlo
• Differential Cross Section
• Feynman Diagram
• Feynman Rule