EPJ Web of Conferences (Jan 2017)
New experimental results for the 17 MeV particle created in 8Be
Abstract
Electron-positron angular correlations were remeasured for the 17.6 MeV (Jπ = 1+ → 0+) ground state transition in 8Be using an improved setup compared to the one we used previously. Significant deviations from the internal pair creation was observed at large angles in the angular correlations, which supports that, in an intermediate step, a neutral isoscalar particle with a mass of 17.0 ±0.2(stat) ±0.5(sys) MeV/c2 and Jπ = 1+was created.