Searching for a new force at VEPP-3

We propose an experiment to search for a new gauge boson, A${}^{\mathrm{\prime }}$, in $e^{+}{e}^{-}$ annihilation by means of a positron beam incident on a gas hydrogen target internal to the VEPP-3 storage ring. The search method is based on a missing mass spectra in the reaction $e^{+}{e}^{-}\to \gamma$ A${}^{\mathrm{\prime }}$. It allows observation of the A${}^{\mathrm{\prime }}$ signal independently of its decay modes and life time. The projected result of this experiment corresponds to an upper limit on the square of coupling constant $|f_{e$\text{A}${^\prime}}|^2=1\cdot 10^{-8}$withasignal-to-noiseratiooffivetooneatanA$^\prime$ mass of 15 MeV.