Nonlinear Phenomena in Complex Systems, 2001, Vol.4, No.3, pp.310-317

NONLINEAR PHENOMENA IN COMPLEX SYSTEMS
An Interdisciplinary Journal

2001, Volume 4, Number 3, pp.310-317

New Physics Effects in Fermion-pair Production at e⁺e^- Colliders
D. Balaschenko, E. Korshunov, and A. Pankov

Fermion compositeness, and other types of new physics that can be described by the exchange of very massive particles, can manifest themselves as the result of an effective four-fermion contact interaction. In the case of the processes e⁺e^- -> mu⁺mu^-, tau⁺tau^-, b¯b and c¯c at future e⁺e^- colliders with sqrt(s) = 0.5 - 1 TeV, we examine the sensitivity to four-fermion contact interactions of two new integrated observables, sigma₊ and sigma_-, conveniently defined for such kind of analysis. We find that, if longitudinal polarization of the electron beam were available, these observables would offer the opportunity to separate the helicity cross sections and, in this way, to derive model-independent bounds on the relevant parameters.
Key words: four-fermion contact interaction, collider, polarization

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