Further Search For A Neutral Boson With A Mass Around 9 Mev/C(2)

Two dedicated experiments on internal pair conversion (LPC) of isoscalar M1 transitions were carried out in order to test a 9 MeV/c(2) X-boson scenario. In the Li-7(p, e(+)e(-))Be-8 reaction at 1.1 MeV proton energy to the predominantly T = 0 level at 18.15 MeV, a significant deviation from IPC was observed at large pair correlation angles. In the B-11(d, ne(+)e(-))C-12 reaction at 1.6 MeV, leading to the 12.71 MeV 1(+) level with pure T = 0 character, an anomaly was observed at similar to9 MeV/c(2). The compatibility of the results with the scenario is discussed.