Search for muon catalyzed \(d^3He\) fusion

This report presents the results of an experiment aimed at observation of the muon catalyzed \(^3\!He\;d\) fusion reaction \(^3\!He + \mu\;d\to^3\!He\;\mu\;d\to^4\!He(3.66MeV)+p(14.64MeV)+\mu\) which might occur after a negative muon stop in the \(D_2+^3\!He\) gas mixture. The basic element of the experimental setup is a Time Projection Chamber (TPC) which can detect the incoming muons and the products of the fusion reaction. The TPC operated with the \(D_2 + ^3\~He (5%)\) gas mixture at \(31K\) temperature. About \(10^8\) \(^3\!He\;\mu\;d\) molecules were produced with only 2 registered candidates for the muon catalyzed \(^3\!He\;d\) fusion with the expected background \(N_{bg}=2.2\pm 0.3\) events. This gives an upper limit for the probability of the fusion decay of the \(^3\!He\;\mu\;d\) molecule \(P_{F}(^3\!He\;\mu\;d)\leq 1.1\cdot 10^{-7}\) at 90% C.L. Also presented are the measured formation rate of the \(^3\!He\;\mu\;d\) molecule \(\lambda_{d3He}=192(3)\cdot 10^6 s^{-1}\) and the probability of the fast muon transfer from the excited to the ground state of the \(\mu\;d\) atom \(q_{1S}=0.80(3)\).