Measurement of the neutron-proton spin correlation coefficient Ayy at 90° c.m. by elastic scattering of 13.7 MeV polarized neutrons from a polarized proton target

The neutron-proton spin correlation coefficient Ayy was measured at 90° c.m. by elastic scattering of 13.7 MeV polarized neutrons from a polarized proton target. The target polarization of about 60% was produced in a LMN single crystal by dynamic nuclear orientation using 70 GHz microwaves. The target was thin enough to allow the detection of the recoil protons in coincidence with the associated scattered neutrons. Our result for Ayy is the first experimental determination of a neutron-proton spin correlation parameter at such a low energy. To determine the influence of Ayy on the ³S1-³D1 mixing parameter ε1, a single-energy n-p phase shift analysis was performed using the experimentally determined value of Ayy= 0.078 ± 0.014 along with analyzing power and cross section data. As expected, the result for ε1 changes drastically upon the inclusion of Ayy. An unexpectedly small value of ε1 = -0.16°±0.54° has been obtained in the present analysis. © 1988.

Duke Scholars

Author Werner Tornow Physics