Polarized 3He, Polarized Neutrons and New Interactions beyond the Standard Model

Dr. Haiyang Yan (Institute of Nuclear Physics and Chemistry)
Sep. 22, 2016(Thu), 3:30 PM,  #1323(E6-2, 1st fl.)

Polarized spins are good probes to detect spin dependent new interactions beyond the standard model. In recent years, various models of new physics beyond the standard model have been studies in which new massive particles such as axion, familon,and majoron, etc. were theoretically introduced. Many of these exotic new interactions are spin dependent. Spin polarized neutron beam, atom beam or noble gases are good probes to detect these new interactions. We used spin rotation of polarized neutrons in liquid Helium to search for spin-velocity dependent new interactions. The new upper bound we obtained is more than 7 orders of magnitude more stringent than the existing laboratory constraints for interaction ranges below 1 m. We Searched for New Spin and Velocity-Dependent Interactions by spin relaxation of polarized 3He Gas. Using the best available measured T2 of polarized 3He gas atoms as the polarized source and the Earth as an unpolarized source, we obtain constraints on two new interactions. We present a new experimental upper bound on possible vector-axial-vector (VVA) type interactions for ranges between 1 and 108m.