Speaker
Description
The ordinary muon capture (OMC) is a process where a nucleus captures a negative muon from the lowest atomic orbital, the 1s orbital, and modern muon facilities in Japan and Switzerland can produce these muons and shoot them at target atoms. The mass of the captured muon is some 100 MeV, thus introducing momentum exchanges in the range of 100 MeV, in the ballpark of the momentum exchanges involved in the neutrinoless double beta decay (NDBD). In NDBD-minus decaying nuclei the OMC on the NDBD daughter populates the states of the intermediate nucleus of the NDBD, like in the case of 136-Xe NDBD the capture on 136-Ba populates the states of 136-Cs. Both processes, NDBD and OMC, populate intermediate/final states of high excitation energies and high angular momentum. This is how the OMC probes effectively the wave functions of all the intermediate states relevant for the NDBD. Furthermore, the rates of both processes depend strongly on the value of the weak axial coupling, $g_{\rm A}$, the effective values of which are not well known in the NDBD nuclei. This dependence of the OMC on weak couplings adds to its importance as a probe of the NDBD.
