HAL : in2p3-00193433, version 1
 arXiv : hep-ph/0112256
 DOI : 10.1007/s100520200905
 European Physical Journal C 23 (2002) 633-649
 New method for calculating helicity amplitudes of jet--like QED processes for high--energy colliders I. Bremsstrahlung processes
 (2002)
 Inelastic QED processes, the cross sections of which do not drop with increasing energy, play an important role at high-energy colliders. Such reactions have the form of two-jet processes with the exchange of a virtual photon in the t-channel. We consider them in the region of small scattering angles $m/E \lesssim \theta \ll 1$, which yields the dominant contribution to their total cross sections. A new effective method is presented and applied to QED processes with emission of real photons to calculate the helicity amplitudes of these processes. Its basic idea is similar to the well-known equivalent-lepton method. Compact analytical expressions for those amplitudes up to $e^8$ are derived omitting only terms of the order of $m^2/E^2, \theta^2$, $\theta m/E$ and higher order. The helicity amplitudes are presented in a compact form in which large compensating terms are already cancelled. Some common properties for all jet-like processes are found and we discuss their origin.
 Thème(s) : Physique/Physique des Hautes Energies - Phénoménologie
 Lien vers le texte intégral : http://fr.arXiv.org/abs/hep-ph/0112256
 in2p3-00193433, version 1 http://hal.in2p3.fr/in2p3-00193433 oai:hal.in2p3.fr:in2p3-00193433 Contributeur : Dominique Girod <> Soumis le : Lundi 3 Décembre 2007, 15:47:55 Dernière modification le : Lundi 3 Décembre 2007, 15:59:00