Eur. Phys. J. C (2011) 71: 1680
https://doi.org/10.1140/epjc/s10052-011-1680-8

Regular Article - Theoretical Physics

Radiative events as a probe of dark forces at GeV-scale e ⁺ e ⁻ colliders

¹ Dipartimento di Fisica Nucleare e Teorica, Università di Pavia, Via A. Bassi 6, 27100, Pavia, Italy
² INFN, Sezione di Pavia, Via A. Bassi 6, 27100, Pavia, Italy
³ School of Physics & Astronomy, University of Southampton, Southampton, SO17 1BJ, UK

^* e-mail: fulvio.piccinini@pv.infn.it

Received: 13 January 2011
Revised: 1 April 2011
Published online: 23 June 2011

Abstract

High-luminosity e ⁺ e ⁻ colliders at the GeV scale (flavor factories) have been recently recognized to be an ideal environment to search for a light weakly coupled vector boson U (dark photon) emerging in several new physics models. At flavor factories a particularly clean channel is the production of the U boson in association with a photon, followed by the decay of the U boson into lepton pairs. Beyond the approximations addressed in previous works, we perform an exact lowest order calculation of the signal and background processes of this channel. We also include the effect of initial- and final-state QED corrections neglected so far, to show how they affect the distributions of experimental interest. We present new results for the expected statistical significance to a dark photon signal at KLOE/KLOE-2 and future super-B factories. The calculation is implemented in a new release of the event generator BabaYaga@NLO, which is available for full event simulations and data analysis.