PHEGAS: a phase-space generator for automatic cross-section computation

TL;DR

A phase-space generation algorithm, capable to efficiently integrate the squared amplitude of any scattering process, is presented, implemented in a Monte Carlo program, PHEGAS, which, using HELAC, a helicity amplitude computational package, can be used for automatic cross-section computation and event generation.

Abstract

A phase-space generation algorithm, capable to efficiently integrate the squared amplitude of any scattering process, is presented. The algorithm has been implemented in a Monte Carlo program, PHEGAS, which, using HELAC, a helicity amplitude computational package,can be used for automatic cross-section computation and event generation. Results for several scattering processes with four, five and six particles in the final state are briefly presented.

Figures (2)

• Figure 1: Feynman graph contributing to $e^-\; e^+\to \mu^-\; \bar{\nu}_\mu\; u\; \bar{d}$.
• Figure 2: Differential distribution of the invariant masses $m_{b-W^+}$ and $m_{\bar{b}-W^-}$ for the process $gg\to b\bar{b}b\bar{b}W^+W^-$.