Nucleon Decay into Dark Sector
  A sub-GeV dark sector fermion X can have baryon number violating interactions induced by high scale physics, leading to nucleon decay into X + meson and neutron -> X + photon. Such processes can mimic standard search modes containing a neutrino, but have different kinematics and may have escaped detection. If a dark force mediated by a light vector Z_d acts on X, depending on parameters, neutron -> X + Z_d can be important. In typical scenarios, Z_d decays into l^+l^-, where l=e, mu, with order unity branching fraction. Nucleon decay searches can potentially uncover new dark states that are otherwise inaccessible, due to their negligible coupling to ordinary matter or cosmological abundance. 
Hooman Davoudiasl
hep-ph hep-ex