2002/07/18 by M. L. Nekrasov · 1 citation
Physics and Astronomy · #Economics #Microeconomics #Particle physics #Particle physics theoretical and experimental studies #Perturbation theory (quantum mechanics) #Physics #Production (economics) #hep-ph
paper · pdf · doi:10.1016/s0370-2693(02)02549-2
published as Phys.Lett. B545 (2002) 119-126 · LaTeX, 11 pages, 3 eps figures
arxiv created 2002/07/18 · openalex publication_date 2002/10/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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- → (γ,Z) → t t → W+b:W- 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.