Simulation of electron-positron annihilation into hadrons with the event generator PHOKHARA

TL;DR

This paper presents an extended Monte Carlo event generator, PHOKHARA, capable of simulating electron-positron annihilation into hadrons with higher order radiative corrections, improving precision for low energy collider experiments.

Contribution

The paper introduces an extended version of PHOKHARA that includes simulations with multiple real and virtual photons at next-to-next-to leading order, enhancing accuracy in modeling hadronic final states.

Findings

PHOKHARA's stability and consistency are validated.

Comparison with KKMC and MCGPJ shows good agreement.

Implications for hadronic cross section analysis are discussed.

Abstract

The precise determination of the cross section for electron-positron annihilation into hadrons is one of the central tasks of ongoing experiments at low energy colliders. These measurements have to be complemented by Monte Carlo generators which simulate a large number of final states and include higher order radiative corrections. With this motivation in mind the generator PHOKHARA is extended to allow for the simulation of final states with zero, one or two real photons. At the same time corrections from the emission of one or two virtual photons are included, such that a full next-to-next-to leading order generator is available. The stability and consistency of the program is tested. The results (for muon-pair final states) are compared to the programs KKMC and MCGPJ and implications for the analysis of various hadronic final states are investigated.