Novel shell-model analysis of the $^{136}$Xe double beta decay nuclear matrix elements

Understand

Neutrinoless double beta decay, if observed, could distinguish whether neutrino is a Dirac or a Majorana particle, and it could be used to determine the absolute scale of the neutrino masses.

• $^{136}$Xe is one of the most promising candidates for observing this rare event.
• However, until recently there were no positive result for the allowed and less rare two-neutrino double beta decay mode.
• The small nuclear matrix element associated with the small half-life represents a challenge for nuclear structure models used for its calculation.