Dinko Pocanic and Stefan Baessler, in collaboration with colleagues from Arizona State University and Oak Ridge National Lab, have received funding for the development of a spectrometer optimized for precise measurements of correlations in neutron beta decay. The recently approved National Science Foundation Major Research Instrumentation grant totals approximately $2.5M, of which $2.3M will go to UVa. Furthermore, the Department of Energy will provide an additional $2M to fund the balance of the equipment required to complete "Nab," the first experiment in the planned series of measurements. The spectrometer will be installed at the world's most powerful pulsed neutron source, the Spallation Neutron Source at the Oak Ridge National Lab in Tennessee.

The spectrometer was designed by the Nab collaboration, at present a group of 27 scientists from 13 institutions, with design leadership provided by the UVa group. The goal of the collaboration is to measure the correlation between the neutrino and electron directions in the beta decay of the free neutron. This measurement will provide important input for the theory of the weak interaction. For example, the result will be used to search for hitherto unseen, hypothetical elementary particles that would cause the so-called scalar and tensor interactions. The spectrometer will be subsequently modified for use in follow-on measurements of spin correlations in neutron beta decay. Training of graduate and undergraduate students, as well as postdoctoral fellows, is one of the major goals of this collaborative research effort.

More information can be found at http://nab.phys.virginia.edu