Observation of Anomalous Internal Pair Creation in ${}^8$Be: A Possible Signature of a Light, Neutral Boson

A. J. Krasznahorkay, M. Csatlós, L. Csige +11

Electron-positron angular correlations were measured for the isovector magnetic dipole 17.6 MeV state ($J^{\pi }=1^{+}$, $T=1$) $\to$ ground state ($J^{\pi }=0^{+}$, $T=0$) and the isosc…