Implications of an Improved Neutron-Antineutron Oscillation Search for Baryogenesis: A Minimal Effective Theory Analysis.

Future neutron-antineutron (n-n[over ¯]) oscillation experiments, such as at the European Spallation Source and the Deep Underground Neutrino Experiment, aim to find first evidence of baryon number violation. We investigate implications of an improved n-n[over ¯] oscillation search for baryogenesis via interactions of n-n[over ¯] mediators, parametrized by an effective field theory (EFT). We find that even in a minimal EFT setup there is overlap between the parameter space probed by n-n[over ¯] oscillation and the region that can realize the observed baryon asymmetry of the Universe. The mass scales of exotic new particles are in the tera-electron-volt-peta-electron-volt regime, inaccessible at the LHC or its envisioned upgrades. Given the innumerable high energy theories that can match, or resemble, the minimal EFT that we discuss, future n-n[over ¯] oscillation experiments could probe many viable theories of baryogenesis beyond the reach of other experiments.