Minutes (well, hours) of April 2 Meeting
Steve Geer announced plans for a letter of interest to be sent
to the Fermilab Directorate, signed by as many physicists possible
saying that there is a community who is interested in persuing
neutrino oscillation physics beyond the next round of experiments.
This would not represent any kind of binding contract, simply the
expression of interest in the field, in hopes that Fermilab
continues to play an important role in measuring the matrix elements
of the neutrino mixing matrix. The goal is that there be at least 300
physicists who will lend their support to the letter.
Kevin McFarland gave a summary of what the HEPAP subpanel on the
future of the field has been hearing, and when future meetings
will occur. Their first meeting was in Washington last week, where
the committee had cold water thrown in their faces by outgoing
government officials.
So far the neutrino factory aspect of the muon collider
studies has not been emphasized, and many on the committee don't realize
that the neutrino factory is something that could occur significantly
before a high energy muon collider. The next presentations to
the committee will be:
-April 19-20 at Brookhaven
-May 23-24 at SLAC
-June 11-12 at Fermilab (user's meeting)
Requests for time for presentations should be made either through
Kevin or directly to Barry Barish and John Bagger, who are the chairs of
the committee. There are already neutrino factory talks expected at
Brookhaven, Steve Geer agreed to ask Mike Shaevitz for some air time
at Fermilab. Larry Wai at SLAC will see what he can do as well.
We also discussed the issue of how to fire the public's imagination
about high energy physics, and how can we get more public interest and
support.
There was also some talk about how the committee would be using
Snowmass, it was hoped that they would be able to repond in some
"town meeting" forum to what they've
been hearing so far, at Snowmass at the end of the 3-week session, although
it's not clear that the Snowmass organizers had that in mind as well.
Ideas for the Fermilab Users Committee meeting were 4 15-minute talks,
on
-Theory
-Conventional Beams--the next step
-Neutrino Factory
-R&D
Our group needs to make the most of Snowmass, and take advantage
of the synergy between the neutrino factory and as many other
groups as possible (for example, the UNO folks).
Brief discussion on what to do with the Superbeams report--Debbie will
write a cover letter and present it to Mike Shaevitz, and then it will
be moth-balled until after Snowmass, where if there's enough interest
we may add to it (filling in some gaps like liquid scintillators,
hybrid emulsion detectors, improvements in the water cerenkov
background rejection, and lower energy beams) and try to publish it
(possibly in PRD).
Discussion on Detector R&D for the Next Big Neutrino Experiment
We need to write a document for the directorate due May 15, on what the
detector R&D needs to happen for the next big neutrino experiment.
It's assumed that the detector R&D would be broken into
three different paths:
either detectors for conventional beams (i.e. nu-e appearance) or
detectors for neutrino factories ("wrong-sign" muon appearance) or
massive tau detectors. We brainstormed on these three
topics, and assorted comments are given below:
-Neutrino Factory
1) Steel-Based
-What is optimal steel segmentation (Jeff Nelson has looked into
this and promised to continue--from both a B-field point of view
and also an event energy reconstruction point of view).
-What's the cheapest readout technology we can stand?
-What really limits the size of this detector?
-Above ground / Below ground questions--or "how far below ground
does this have to be for wrong-sign muon id?"
2) Water-Based
-Need to find out what the newest water geometry is, and
how one could add b-field. With very small volumes, the
difference between a water-cerenkov and a steel-based detector
gets minimized simply because of ratio of densities.
-Need real acceptance model based on updated geometry
-What is the minimum pmt coverage?
-need to develop large but cheap tubes that work in a B field
Ferenc at UC Davis was mentioned. One should look into LHCB's RICH
detector.
-How does the added spectrometer tie into UNO's veto? they need
3-4m of clear space for that.
-One could also look into ATLAS's pmt's.
-Conventional Beams
it was emphasized here that we really need to understand
before building a large detector what the real nc pi0 rejection
would be, and that would have to come from putting these detectors
in an actual neutrino beam. Also, there was discussion of having a
very fine-grained detector as a near detector regardless of the far
detector's design to pinpoint exactly what the beam-related nue fraction
is. For example, 10^4 NC events in a fine-grained near detector are needed to
get measurements of a rejection that is expected to be 10^-3! Is there anyone
doing these kinds of studies on the near detector k2k data? (of course
there is...but who?)
-Need to quantify NC pi0 production uncertainties
-Need to quantify low energy neutrino cross section uncertainties...
1) Emulsion-Steel
- NC pi0 production needs to be better understood
2) Water Cerenkov
- Minimum pmt coverage, any hope on getting more pi0- rejection?
3) Liquid Argon
Is there a benefit of magnetic field in liquid argon?
what is the minimum granularity?
TPC literature search useful here...
is there any way to make the detector concept more massive?
what ultimately limits the size?
- Tau Detectors
-How much can one get out of statistical separation?
(expected to be more of a handle at a neutrino factory)
-Line shape measurement?
-How does nc/cc ratio enter into this?
-Do we really need event by even tau detection?
-If so, what is heaviest way to use emulsion?
-Optimization of drift space, steel thickness, and emulsion thickness
Finally, meeting at 2PM Monday afternoons has been proposed, since a number
of folks can't make Wednesday 9:30 meetings.
Debbie Harris
Debbie Harris
Last modified: Mon Apr 9 10:45:09 CDT 2001