Exotic Interactions

Extensions of the Standard Model of Particle Physics usually predict new particles and therefore also new interactions. One possible spin-dependent interaction between a nucleon and a new vector boson (spin 1) can be tested using a polarized probe and an unpolarized sample in close proximity. The axial coupling of the sample would create a pseudo-magnetic field that can be precisely measured using Ramsey’s technique of separated oscillatory fields. The current best limits on this interaction, for an interaction length of less than 8 mm, were established using a polarized neutron beam and a copper sample [Piegsa & Pignol, Phys. Rev. Lett. 108, 181801 (2012)]. In our group, we plan to improve this limit with neutrons, but also extend this search to the axial coupling to protons, using NMR techniques with protons in flowing water.

Preliminary sketch of the experimental NMR setup.