title: Searching for New Spin- and Velocity-Dependent Interactions by Spin Relaxation of Polarized ^{3}He Gas.
abstract: We have constrained possible new interactions which produce nonrelativistic potentials between polarized neutrons and unpolarized matter proportional to ασ[over →]·v[over →] where σ[over →] is the neutron spin and v[over →] is the relative velocity. We use existing data from laboratory measurements on the very long T_{1} and T_{2} spin relaxation times of polarized ^{3}He gas in glass cells. Using the best available measured T_{2} of polarized ^{3}He 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 (V_{VA}) type interactions for ranges between 1 and 10^{8} m. In combination with previous results, we set the most stringent experiment limits on g_{V}g_{A} ranging from ~μm to ~10^{8} m. We also report what is to our knowledge the first experimental upper limit on the possible torsion fields induced by the Earth on its surface. Dedicated experiments could further improve these bounds by a factor of ~100. Our method of analysis also makes it possible to probe many velocity dependent interactions which depend on the spins of both neutrons and other particles which have never been searched for before experimentally.
authors.affiliation: Key Laboratory of Neutron Physics, Institute of Nuclear Physics and Chemistry, CAEP, Mianyang, Sichuan 621900,China.
authors.forename: H
authors.initials: H
authors.lastname: Yan
authors.affiliation: Key Laboratory of Neutron Physics, Institute of Nuclear Physics and Chemistry, CAEP, Mianyang, Sichuan 621900,China.
authors.forename: G A
authors.initials: GA
authors.lastname: Sun
authors.affiliation: Institute of Nuclear Physics and Chemistry,CAEP, Mianyang, Sichuan 621900,China.
authors.forename: S M
authors.initials: SM
authors.lastname: Peng
authors.affiliation: Key Laboratory of Neutron Physics, Institute of Nuclear Physics and Chemistry, CAEP, Mianyang, Sichuan 621900,China.|School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physics, Shanghai Jiaotong University, Shanghai 200240, China.
authors.forename: C
authors.initials: C
authors.lastname: Fu
authors.affiliation: Department of Physics, Southeast University, Nanjing 211189, China.
authors.forename: H
authors.initials: H
authors.lastname: Guo
authors.affiliation: Key Laboratory of Neutron Physics, Institute of Nuclear Physics and Chemistry, CAEP, Mianyang, Sichuan 621900,China.
authors.forename: B Q
authors.initials: BQ
authors.lastname: Liu