Search for a massless dark photon in $Λ^{+}_{c}\to p γ^{\prime}$ decay

Abstract

A search for a massless dark photon $γ^{\prime}$ is conducted using 4.5 ${\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at center-of-mass energies between 4.600 and 4.699 $\mathrm{GeV}$ with the BESIII detector at BEPCII. No significant signal is observed, and the upper limit on the branching fraction $\mathcal{B}(Λ^{+}_{c}\to p γ^{\prime})$ is determined to be $8.0\times 10^{-5}$ at 90% confidence level.

9 Pages, 5 figures