A new approach to search for free neutron-antineutron oscillations using coherent neutron propagation in gas

Abstract Coherent forward neutron propagation in gas is discussed as a new approach to search for neutron-antineutron oscillations ( n − n ¯ ), which violate both B and B − L conservation. We show that one can increase the probability of neutron - antineutron transitions in the presence of a nonzero external magnetic field to essentially free neutron oscillation probability by tuning the density of an appropriate mixture of gases so that the neutron optical potential of the gas cancels that from the magnetic field.