Neutron-Antineutron oscillation as a test of a New Interaction

Abstract

We propose to search Neutron-Antineutron transitions, in condition of strong magnetic field rather than suppressed one. It is commonly accepted that such an oscillation has to be searched in no magnetic field conditions (for instance, the experiment have to be shielded by the Earth’s magnetic field). But, Neutron (and Antineutron) could be coupled to a 5th force spin-independent background Φ generated by the Earth, as eV Φ¯nγ0n. The background condensate simulates a difference in neutron and antineutron masses, in other words a CPT violation. Compatible with Equivalence Principle (EP) limits for a neutron inside nuclei, the 5th force background could be as high as Φ ∼ 10 −11 ÷ 10 −10 eV. As consequence, the transition probability is amplified rather than suppressed with a magnetic field of B ∼ 1–10 Gauss, if we consider neutrons immersed in a background saturating the EP limit. There are intriguing connections among: the existence of a Majorana neutron, Baryon violations Beyond the Standard Model, the Matter-Antimatter asymmetry in our Universe (Baryogenesis and Leptogenesis), the possibility of a new fifth force interaction, the possible apparent violation of the Equivalence Principle and the CPT. These strongly motivate an improvement of our current best limits in n-¯n physics.