Braidwood Neutrino Experiment

Dear HEPAP Member,

As a member of HEPAP, we would like to encourage
your support for a future strong US neutrino
program. As outlined in the recent APS neutrino
study, the field could have a golden opportunity
to probe for CP violation in neutrino mixing if
the last unknown mixing angle, theta13, is not too
small (> 5 degrees). Determining the size of
theta13 is therefore the key next step.

We believe that the most straightforward and cost
effective method to make this determination is a
two detector experiment at a nuclear reactor. To
this end, our collaboration for the Braidwood
reactor site has developed a US experiment with
discovery sensitivity at the above level. In
addition, the experiment is designed to be robust
with respect to systematic uncertainties and to
have the capability to see a positive signal, if
it exists, in both the neutrino interaction rate
and spectral shape.

After several years of community explorations of
possible locations, it appears that Braidwood is
the best and probably only viable site in the US
for such an experiment. The Exelon Corporation,
which runs the Braidwood reactor, strongly
supports the experiment and has recently allowed
us to dig 600 ft deep bore holes to characterize
the geology of the proposed detector sites.
Overall, the progress for Braidwood has been
excellent and has prompted our submission of a
proposal to the NSF and DOE to support the work
needed to complete the civil and detector
engineering. With the proposed funding, we
believe that we could submit a full proposal in
FY06, start construction in FY07, and begin data
taking in FY10.

In summary, the Braidwood experiment is a great
opportunity for the US program to continue strong
leadership in neutrino physics and to solidify the
case for an upgraded long baseline program if
theta13 is shown to be large enough. We therefore
encourage your support of our efforts.

Sincerely,

Ed Blucher and Mike Shaevitz
Spokespersons for the
Braidwood Neutrino Experiment
http://braidwood.uchicago.edu/
Received on Thu Feb 10 13:33:55 2005