Light dark forces at flavor factories

TL;DR

This paper presents an exact tree-level calculation of light dark force boson production at flavor factories, including higher-order corrections, and implements it in a generator for experimental analysis.

Contribution

It provides a precise calculation and a new generator tool for analyzing light dark force signals at flavor factories, improving upon previous approximations.

Findings

Exact tree-level calculation of U boson production and decay.

Implementation of the calculation in the BabaYaga@NLO generator.

Analysis of the statistical significance of U boson signals.

Abstract

SuperB experiment could represent an ideal environment to test a new U (1) symmetry related to light dark forces candidates. A promising discovery channel is represented by the resonant production of a boson U, followed by its decay into lepton pairs. Beyond approximations adopted in the literature, an exact tree level calculation of the radiative processes $e+ e- \rightarrow \gamma, U \rightarrow \mu^+ \mu^- \gamma, e^+ e^- \gamma$ and corresponding QED backgrounds is performed, including also the most important higher-order corrections. The calculation is implemented in a release of the generator BabaYaga@NLO useful for data analysis and interpretation. The distinct features of U boson production are shown and the statistical significance is analysed.