Speaker
Dr
Tomonari Miyashita
(California Institute of Technology)
Description
We report on a search for single-photon events in 53 $fb^{-1} of $e^+e^- $ collision data collected with the BaBar
detector at the PEP-II $B$-factory. We look for events with a single high-energy photon and a large
missing momentum and energy, consistent with production of a spin-1 particle $A’$ through the
process $e^+e^- \to \gamma A’$, $A’ \to invisible$. Such particles, referred to as “dark photons”,
are motivated by theories applying a $U(1)$ gauge symmetry to dark matter.
We find no evidence for such processes and set 90\% confidence level upper limits on the
coupling strength of $A’ \to e^+e^-$ for a dark photon with a mass lower than 8 GeV.
In particular, our limits exclude the values of the $A’$ coupling suggested by the
dark-photon interpretation of the muon (g-2) anomaly, as well as a broad range of parameters.
Primary author
Prof.
Frank Porter
(Caltech)