Modified perturbation theory approach for tt-bar production and decay

Abstract

The modified perturbation theory (MPT), based on direct expansion of probabilities instead of amplitudes, allows one to avoid divergences in the phase-space integrals resulting from production and decay of unstable particles. In the present paper the range of applicability of MPT is determined numerically in the case of the process $e^{+}{e}^{-}\to (\gamma ,Z)\to t\bar{t}\to W^{+}b:W^{-}\bar{b}$. It is shown that with the complete expansion in powers of the coupling constant (without Dyson resummation) MPT operates best at the energies located near the maximum of the cross-section and slightly above the maximum. In this region the MPT expansion within the next-to-leading order considerably exceeds in accuracy well-known DPA approach.

LaTeX, 11 pages, 3 eps figures

References in corpus (3)

• Electroweak two-loop corrections to the MW-MZ mass correlation in the Standard Model
• OMS-bar scheme of UV renormalization in the presence of unstable fundamental particles
• TESLA Technical Design Report Part I: Executive Summary

Cited by in corpus (7)

• Effective theory calculation of resonant high-energy scattering
• Four-fermion production near the W pair production threshold
• Production-decay interferences at NLO in QCD for t-channel single-top production
• Elektroweak one-loop corrections for e^+e^- annihilation into t\bar{t} including hard bremsstrahlung
• Modified perturbation theory for pair production and decay of fundamental unstable particles
• Pair production of fundamental unstable particles in modified perturbation theory in NNLO
• W-pair production in modified perturbation theory