Limit on the Radiative Neutrinoless Double Electron Capture of $^{36}$Ar   from GERDA Phase I
  Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of $^{36}$Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of $^{36}$Ar was established: $T_{1/2} > $ 3.6 $\times$ 10$^{21}$ yr at 90 % C.I. 
M. Agostini, M. Allardt, A.M. Bakalyarov, M. Balata, I. Barabanov, N.   Barros, L. Baudis, C. Bauer, E. Bellotti, S. Belogur...
nucl-ex hep-ex