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. The proton 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 here.
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?
Deborah Harris
Last modified: Wed Apr 11 13:21:23 CDT 2001