Nuclear Matrix Elements for Neutrinoless Double Beta Decay from Lattice QCD

David Murphy, William Detmold
2019 Proceedings of The 36th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2018)   unpublished
While neutrino oscillation experiments have demonstrated that neutrinos have small, nonzero masses, much remains unknown about their properties and decay modes. One potential decay mode -neutrinoless double beta decay (0νβ β ) -is a particularly interesting target of experimental searches, since its observation would imply that the neutrino is a Majorana particle, demonstrate that lepton number conservation is violated in nature, and give further constraints on the neutrino masses and mixing
more » ... asses and mixing angles. Relating experimental constraints on 0νβ β decay rates to the neutrino masses, however, requires theoretical input in the form of non-perturbative nuclear matrix elements which remain difficult to calculate reliably. In this talk we will discuss progress towards first-principles calculations of relevant nuclear matrix elements using lattice QCD and effective field theory techniques, assuming neutrinoless double beta decay mediated by a light Majorana neutrino. We will show preliminary results for the π − → π + e − e − transition amplitude computed on a 16 3 × 32 domain wall fermion lattice with a pion mass of 420 MeV, and discuss improved methods applicable to general lattice calculations of 0νβ β decay amplitudes.
doi:10.22323/1.334.0262 fatcat:sltbltqm5vanzjt37fy4o5fb7q