ee$\in$MC: Simulation of $e^{+}{e}^{-}\to Hadrons(n\gamma )$ Events

Abstract

The ee$\in$MC generator package is extended to include $e^{+}{e}^{-}\to Hadrons(n\gamma )$ events where the photons can be generated in either the initial-state or final-state production. In particular, the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}(n\gamma )$, $e^{+}{e}^{-}\to {\rm Y}(4s)(m\gamma )\to B^{+}{B}^{-}(n\gamma )$ and $e^{+}{e}^{-}\to {\rm Y}(4s)(m\gamma )\to B^0{\bar{B}}^{-}(n\gamma )$ decay channels have been implemented in the generator. The B-mesons are not decayed in ee$\in$MC, but are left for other generators that specialized in B-mesons. Both the initial-state-radiation and final-state-radiation are simulated using the Yennie-Frautschi-Suura Exponentiation procedure \cite{Yennie:1961}, where several effective models are implemented to investigate the assumption of the radiative structure of the final-state vertex. The impact of these radiative models on the $e^{+}{e}^{-}\to {\rm Y}(4s)(m\gamma )\to B^{+}{B}^{-}(n\gamma )$ and $e^{+}{e}^{-}\to {\rm Y}(4s)(m\gamma )\to B^0{\bar{B}}^{-}(n\gamma )$ processes, excludes some models, particularly, in regards to the Coulomb potential. This has an important impact for meson and baryon systems near threshold.

Comments: 8 pages, 4 Figures