Last Mixing Angle
In measuring neutrinos coming from both the atmosphere and the sun, we
have learned that neutrinos do possess mass and "oscillate" amongst
each other. The mass splitings between different neutrinos, as
well as the mixing parameters, are now being measured with increasing
precision. One of these parameters --theta13, however, remains to
be measured. If this mixing angle is not too small, it may help
explain why the universe appears to be made mostly of matter rather
So far, the best limits on this mixing angle come
from experiments studying neutrinos produced in nuclear reactors.
The next generation of such experiments is now being developed, with
efforts taking place around the globe. The basic scheme is to use
two 50 ton detectors filled with liquid scintillator to study the
anti-neutrino reaction on hydrogen. The process produces a
neutron, which is later captured. This very technique was how
neutrinos were first discovered.
Current efforts hope to push the limit on theta13 by
about one order of magnitude better than previous measurements.
Documents & Papers of Interest: