April 11 Minutes
In view of the fact that we need to produce a report by May 15 on
Detector R&D, we had a discussion about the framework for that
report. The argument is as follows: if a conventional neutrino beam is
in fact the next step in neutrino physics, then we need both the
increase in the proton power and new beamline, as well as the
increase in the detector mass. And in general we gain by the
square root of any improvement. The assumptions we've been making
so far are that the detector mass would increase by factors of 10
to 20, and that the conventional beam flux would increase by a factor
of 4 from the effects of a proton driver upgrade.
Proton Driver Study Findings
So although we are supposed to focus on the required detector R&D,
we had a discussion about the beamline side to give us some perspective.
driver study found that the NUMI beamline could not take a factor
of 4 increase in rate because of target and Shielding considerations, and the
horns could not be pulsed at 15Hz, which is the expected frequency
of the new proton source. So increasing the beam flux of neutrinos
at least in the NUMI beamline would involve more target R&D, as well
as magnet R&D, since horns might not be appropriate with such a high
beam power. A link to the proton driver study can be found
Important Dates for the Proton Driver Study are:
-May 15 0th level Draft of Physics case for the proton driver
-June 6,7 Workshop at Fermilab on Proton Driver Physics
-following week, 1sh level draft of physics case study.
Brief aside on Workshop on JHF-SuperK neutrino beam:
May 30-31, right after Nufact01, at Tsukuba Epochal--look
here to see
the web page of this workshop.
Next Experiments if LSND is confirmed...
The next discussion jumped to what kinds of experiments become
interesting if LSND is confirmed by MiniBoone (besides Boone, of
course). Fritz DeJongh
talked about trying to do numu to nutau at short (20km) baselines and
high energies, as well as looking at cp violation in the
numu to nue channel at long baselines (since it would have to show
up somewhere around the atmospheric delta m^2). The long baselines
could either be "sub-GeV beams" and 150km, or "multi-GeV" beams and
3000km, according to Fritz. Of course the LSND allowed region in
delta m^2 space is large, so there is an order of magnitude
uncertainty on how long the "20km" baseline actually is.
Matter Effects if LSND Confirmed
We started worrying
about matter effects if lsnd is correct, but it's not clear what
would happen since matter effects would have to appear at the
atmospheric delta m^2, but there you're sensitive to cos(theta13)
not sin(theta13) and there's much more of a change due to matter
in the sin than in the cosine (if the sin is small). Andrea Romanino
and Gabriela Barenboim agreed to look into matter effects in the
case where LSND is confirmed. So the baselines might be different
if LSND is confirmed, and the requirements on a large mass might not
be as stringent, but still getting nue and nutau appearance are
important. One question is: how far can we go if LSND is confirmed
with the current technology?
Last modified: Wed Apr 11 13:21:23 CDT 2001