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Session J10 - Tests of Fundamental Symmetries at Low Energies II: Time Reversal.
MIXED session, Saturday morning, May 04
Room 104,

[J10.05] A Test of Time-Reversal Invariance Using MeV Neutrons and Aligned Holmium

P.\ Huffman, N.\ Roberson, W.\ Wilburn (Duke University and Triangle Universities Nuclear Laboratory), C.\ Gould, D.\ Haase, C.\ Keith, B.\ Raichle, M.\ Seely, J.\ Walston (North Carolina State University and Triangle Universities Nuclear Laboratory)

We have recently performed the most precise direct test of parity (P) conserving, time-reversal (T) invariance in nuclear physics. The experiment involves searching for the P-conserving, T-violating five-fold correlation \vecs \cdot (\vecI \times \veck)(\vecI \cdot \veck) in the neutron-nucleus forward scattering amplitude. The measurement uses 6 MeV polarized neutrons transmitted through a cryogenically aligned rotating holmium target. The amplitude of the T-violating neutron asymmetry is measured to be (11 \pm 10) \times 10^-7, consistent with time-reversal invariance. This corresponds to a T-violating spin-correlation coefficient of (8.6 \pm 7.7) \times 10^-6, which is a factor of 300 improvement in a measurement of a T-invariant sensitive relative cross section. Using the recent work of Engel \itet al. [Phys. Rev. Lett. 73, 3508 (94)], the asymmetry is analyzed in terms of a bound on a P-conserving, T-violating \rho exchange coupling.

Part J of program listing