grcννγ: Event generator for the single- and double-photon emission associated with neutrino pair-production Original Research Article

A new event generator is proposed for two processes e+e−→νν̄γ and e+e−→νν̄γγ where νν̄ includes all the neutrino species. The exact matrix elements of single- and double-photon emission, generated by the GRACE system, are convoluted with the QED parton shower (QEDPS) to deal with the initial state radiations (ISR). It is pointed out that a careful treatment is required to avoid the double counting of the radiative photons between the matrix elements and the ISR part. A detailed comparison of grcννγ with the O(α) calculations and other similar Monte Carlo generators is discussed on the total cross section and on various distributions. It is also examined how the possible effects of the anomalous triple-gauge-boson couplings can be observed.