Neutron-Antineutron Oscillations from Lattice QCD


Fundamental symmetry tests of baryon number violation in low-energy experiments can probe beyond the Standard Model explanations of the matter-antimatter asymmetry of the universe. Neutron-antineutron oscillations are predicted to be a signature of many baryogenesis mechanisms involving low-scale baryon number violation. This work presents the first complete lattice quantum chromodynamics calculation of the six-quark matrix elements needed to connect experimental measurements of the neutron-antineutron oscillation rate to constraints on beyond the Standard Model theories. State-of-the-art lattice gauge field configurations at the physical pion mass are used and the lattice matrix elements are renormalized nonperturbatively and converted to the $\overlineMS$ scheme at 2 GeV, where perturbative scale running can be used to connect them to BSM theories. Phenomenological implications are highlighted by comparing the constraints of proposed neutron-antineutron experiments to predictions of a specific model of post-sphaleron baryogenesis. These results from lattice quantum chromodynamics are also compared to previous estimates from the MIT bag model.

Physical Review Letters
Enrico Rinaldi
Enrico Rinaldi
Research Scientist

My research interests include artificial intelligence and quantum computing applied to particle physics and quantum many-body systems.