Title: Quantifying New Contributions to Neutrinoless Double Beta Decay from Lattice QCD
Abstract: While the discovery of non-zero neutrino masses is among the most important accomplishments by physicists in the past century, it is still unknown how and in what form these masses arise. Lepton number-violating neutrinoless double beta decay is a natural consequence of Majorana neutrinos and many BSM theories, and, if observed, could potentially explain the matter/anti-matter asymmetry in the universe. Several experimental searches for these processes using nuclear sources are planned and/or underway worldwide, and understanding quantitatively how neutrinoless double beta decay would manifest in nuclear environments is key for interpreting any observed signals. Estimates for the necessary size and sensitivity of these experiments rely on model calculations involving only a single mechanism for the decay, light Majorana neutrino exchange. However, it is expected that new heavy, beyond the Standard Model particles will also contribute to this process, and these contributions have been previously unknown even at the two nucleon level. In this talk I will give an overview of microscopic observables relevant for experimental searches for neutrinoless double beta decay which may be calculated directly from QCD using lattice methods, and present new results for potential short-range mechanisms.