Search

Lutetium thermometry has been used to analyze Oklo natural nuclear reactor zones but leads to widely varying and puzzling predictions for the temperatures $T_O$ which in turn impacts bounds on time variation of the fine structure constant $��$. We revisit results for reactor zone RZ10 in light of new measurements of the isomer branching ratio $B^g$ in $^{175}$Lu neutron capture at 5 and 25 keV. We recalculate predictions for $T_O$ as a function of $B^g$ using realistic models of the Oklo neutron flux. We find $T_O = 100 \pm 30$ C using a new value of $B^g$, in contrast to $350 < T_O < 500 $ C using the evaluated value at thermal energy. Lutetium thermometry can be applicable to analyses of Oklo reactor data, but a better measurement of $B^g$ with thermal neutrons is needed to confirm the reliability of temperature predictions., 7 pages, 2 figures

A significant fraction of the research effort at the Triangle Universities Nuclear Laboratory (TUNL) focuses on weak interaction studies and searches for physics beyond the Standard Model. One major effort is the development of a new experimental technique to search for the neutron electric dipole moment (nEDM) that offers the potential for a factor of 100 increase in sensitivity over existing measurements. The search for this moment has the potential to reveal new sources of time reversal (T) and charge-conjugation-and-parity (CP) violation and to challenge calculations that propose extensions to the Standard Model. We provide a brief overview of the experiment as a whole and discuss the work underway at TUNL as part of this effort., Comment: 8 pages, Proceedings of the DPF-2011 Conference, Providence, RI, August 8-13, 2011

Measurements of the transverse polarization coefficient Kyy' for the reaction 3H(p,n)3He are reported for outgoing neutron energies of 1.94, 5.21, and 5.81 MeV. This reaction is important both as a source of polarized neutrons for nuclear physics experiments, and as a test of theoretical descriptions of the nuclear four-body system. Comparison is made to previous measurements, confirming the 3H(p,n)3He reaction can be used as a polarized neutron source with the polarization known to an accuracy of approximately 5%. Comparison to R-matrix theory suggests that the sign of the 3F3 phase-shift parameter is incorrect. Changing the sign of this parameter dramatically improves the agreement between theory and experiment., Comment: 12 pages, RevTeX, 5 eps figures, submitted to Phys. Rev. C

Measurements of polarized neutron--polarized $^3$He scattering are reported. The target consisted of cryogenically-polarized solid $^3$He, thickness 0.04 atom/b and polarization 40%. The longitudinal and transverse total cross-section differences $\Delta\sigma_L$ and $\Delta\sigma_T$ were measured for incident neutron energies 2-8 MeV. The results are compared to phase-shift predictions based on four different analyses of n-$^3$He scattering. The best agreement is obtained with a recent R-matrix analysis of A=4 scattering and reaction data, lending strong suport to the $^4$He level scheme obtained in that analysis., Comment: 19 pages RevTeX style, 5 postscript figures, excepted for publication in the Aug96 issue of Phys. Rev. C. Revised version includes correct version of 1 postscript figure