The Electric Dipole Moment and Parity Violating Spin Rotations of the Neutron

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9321608 Heckel Funding is for two separate experiments. The first is an experiment to measure the electric dipole moment (EDM) of the neutron using ultracold neutrons stored in a bottle. A non-zero neutron EDM would be evidence for a breakdown of both Time Reversal (T) and Parity (P) symmetries. Limits on the neutron EDM are crucial for determining which theoretical explanations for T symmetry violation are correct. The goal of the second experiment is to measure the P violating weak interaction between neutrons and helium nuclei. This information complements other measurements and will help fully parameterized the low energy nucleon-nucleon weak interaction to provide a test of a standard eletroweak theory. We plan to measure the weak-interaction induced rotation of the polarization vector of a transversely polarized cold neutron beam on propagation through 50 cm of liquid helium. The effect, expected to be of order 10-7 radians, represents an unprecedented experimental sensitivity.