Searching for the massless dark photon in c\to uγ'

In the effective field theory, the massless dark photon \gamma' can only couple with the Standard Model particle through operators of dimension higher than four, thereby offering a high sensitivity to the new physics energy scale. Using 7.9~\rm{fb^{-1}} of e^+e^- collision data collected at \sqrt{s}=3.773 GeV with the BESIII detector... Show more