Dr. Bruce Vogelaar
Dr. Mark Pitt
Mark Makela (Ph.D. 2005)
Russell Mammei (Ph.D. 2010)
The well known left-handed asymmetry in the weak interaction is about the only way to let
someone in a distant galaxy know what we mean by right and left.
However, the energy dependence of this asymmetry is fertile ground to explore new physical phenomena,
since the Standard Model makes quite firm predictions, but measurements are not quite there yet.
This experiment utilizes ultra-cold neutrons (UCN's). UCN's scatter elastically off nuclei and can thus be
contained just like a ball in a box. In this experiment the box is non-magnetic so if the UCN's are
put into the box polarized, they tend to stay polarized. Once in the box a UCN bounces around until it
decays into a proton, neutrino, and electron; the electron is then captured by the detectors in the box
and its energy and position are logged. The A-correlation is the energy dependence of asymmetry in the
electron's direction relative to the neutron's polarization.
Ultra-cold neutrons source at Los Alamos confirmed as world's most intense
VT UCN Group Homepage
Los Alamos National Laboratory