Searches for the decays of 64Zn and 112Sn, and the ββ decay transitions of 124Sn to the excited states of 124Te

Search for double-βdecay processes in106Cd with the help of a106CdWOBelli1, Bernabei2, Boiko3 et al. 2012Phys. Rev. C

“…The results of the searches for the capture of two electrons from atomic shells (2ε), electron capture with positron emission (εβ + ), and emission of two positrons (2β + ) are at the level of 10 16 -10 21 yr (see review [2] and original works [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]); although allowed, the two-neutrino mode of these processes has not yet been detected. 1 High-sensitivity experiments to search for neutrinoless 2ε and εβ + decays are also important because they could clarify a contribution of right-handed admixtures in weak interactions [31].…”

First search for double- $ \beta$ decay of platinum by ultra-low background HP Ge $ \gamma$ spectrometry

“…The sensitivity of experiments to search for 2β processes, which transform (A, Z) nucleus to (A, Z − 2): double electron capture (2ε), electron capture with emission of positron (εβ + ), and double positron (2β + ) decay, are on the level of 10 15 − 10 21 yr [3,4,5,6,7,8,9,10,11,12,13,14,15,16]; even allowed in the Standard Model the two neutrino mode is still not observed 2 . At the same time, the investigation of neutrinoless 2ε and εβ + processes could give an important information about possible contribution of the right-handed currents to the neutrinoless double β − decay rate [18].…”

Search for double- β decay processes in 108Cd and 114Cd with the help of the low-background CdWO 4 crystal scintillator

“…The results of the searches for the capture of two electrons from atomic shells (2ε), electron capture with positron emission (εβ + ), and emission of two positrons (2β + ) are at the level of 10 16 − 10 21 yr (see review [2] and original works [11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]); although allowed, the two neutrino mode of these processes has not yet been detected 3 . High sensitivity experiments to search for neutrinoless 2ε and εβ + decays are also important because they could clarify a contribution of right-handed admixtures in weak interactions [31].…”