Recently it has been realized that the production and decay processes of charginos, neutralinos, and sleptons receive corrections which grow like (Formula presented) for large (Formula presented) In this paper we calculate the chargino pair production cross section at (Formula presented) colliders with quark-squark loop corrections. We introduce a novel formulation, where the one-loop amplitude is reorganized into two parts. One part is expressed in terms of the “effective” chargino coupling (Formula presented) and mixing matrices (Formula presented) and includes all (Formula presented) corrections, while the other decouples for large (Formula presented) The form of the one-loop cross section then becomes physically transparent. Our formulation can be easily extended to other loops and processes. Numerically, we find significant corrections due to the effective (Formula presented)-channel coupling (Formula presented) for gaugino-like charginos. In the mixed region, where the chargino has large gaugino and Higgsino components, the corrections due to (Formula presented) are also significant. Our numerical results disagree with a previous calculation. We reexamine previous studies of the determination of (Formula presented) through the measurement of the chargino production cross section. We point out that a previous study, which claimed that the measurement suffers large systematic errors, was performed at a “pessimistic” point in MSSM parameter space. We provide reasons why the systematic errors are not a limiting factor for generic parameter choices.
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 1998|
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)