Searching for a dark photon: Project of the experiment at VEPP-3

TL;DR

This paper proposes an experiment at VEPP-3 to search for a hypothetical dark photon A' using missing mass spectra in electron-positron annihilation, aiming to detect or constrain its properties.

Contribution

It introduces a novel experimental approach to detect dark photons via missing mass spectra, independent of their decay modes or lifetime.

Findings

Projected sensitivity to the coupling constant squared, $oldsymbol{ ext{ε}^2=3 imes 10^{-8}}$

Potential to observe signals at A' masses of 5-20 MeV

Achieves a signal-to-noise ratio of two to one

Abstract

We propose an experiment to search for a new gauge boson A' in $e^+e^-$ annihilation by means of a positron beam incident on a gas hydrogen target internal to the bypass at the VEPP-3 storage ring. The search method is based on a missing mass spectra in the reaction $e^+e^-\rightarrow \gamma$ A'. It allows observation of the A' signal independently of its decay modes and life time. The projected result of this experiment corresponds to an upper limit on the square of the coupling constant $\varepsilon^2=3\cdot 10^{-8}$ with a signal-to-noise ratio of two to one at an A' mass of 5-20 MeV.