19 - April - 2001
FNAL Black Hole
Presentations:-
(This is a draft of a talk to be given next week at DIS01, Bologna.)
For more details, see www.physics.smu.edu/~olness/booster .
Neutrinos are naturally polarized. The use of both neutrinos and antineutrinos gives a handle on the differences between quark and antiquark distributions. In order to improve on previous experiments, we need more intense neutrino beams, and we need to understand them much better.
One can identify two future facilities at Fermilab: NUMI and nuFactory. We will concentrate on NUMI today. It could provide a factor of 1000 in statistics. A second generation experiment could be operative in 2007-8.
NUMI: Know the neutrino flux to 2%. 3.7x10**20 p/year means 3000 CC events/year. There would be very good samples at high Q2 and high Xbj.
There are two concepts for the detector: run parasitically on the MINOS near detector, or build an entirely new detector `MIDOS.' Aim to measure all six structure functions: F2, F1, xF3 for nu/nubar. This has never been done before due to lack of statistics and the use of only one beam type. A typical question would be: Are s(x) and sbar(x) different as a function of Xbj?
One could accumulate good statistics at high y, and investigate hints of interesting nuclear effects: Is the impact of the nuclear environment different for valence and sea quarks?
One could make nice observation of shadowing, which are predicted to be rather different for F2 and xF3.
Comment/request: Please use realistic values of the total power or equiv protons on target (5x10**12). Discussion -> this would probably increase the results shown here by a factor of three.
Comment: The JHF cannot reach the low X we can reach, so the proposed shadowing studies are unique.
On the short term, one would look at neutrinos only, at relatively low Q2. It could be interesting to examine exclusive processes. The axial form factor would be of interest. For example, one could shed some light on the recent controversial measurement on GE/GM from JLab. One could get deltaS from the NC/CC ratio, and the systematics might be better or at least different from the parity violation experiments. Structure function studies would initially be limited in Q2. On the other hand, higher-twist effects could be investigated.
A preliminary detector design is under development, consisting of a cubic meter of scintillator. It would run parasitically with MINOS and be optimized for quasielastic processes. Several obvious improvements can be delineated. A rate estimation is underway.
What can you do with an upgraded beam? Higher luminosity always helps, and higher neutrino energy is beneficial. one could compare nu and nubar. Look at the d/u ratio as Xbj approaches 1, and extract the neutron structure function. Impressive error bars were shown all the way up to X=0.8.
Other possibilities: a liquid target (bubble chamber), intrinsic charm, strange production, polarized targets, even pion structure functions.
Remember leptoquarks `signal' at HERA, which occurred at high Q2. Part of the problem is that we do not know the structure functions up there. That kinematic region is tied via DGLAP to high XBj, lower Q2. New measurements would be very helpful, and also benefit jet studies at the TeVatron.
Nuclear corrections are important at high Xbj, and they cannot be resolved by NMC or HERA data.
Intrinsic charm. EMC data favor a 1% fraction. To see an intrinsic component, it is important to run close to threshold, ie., at low Q2 and high luminosity. The proton driver would be perfect for this.
delta(xF3) = s-c, roughly speaking. Current measurements are poor compared to this difference.
New data from an upgraded proton driver could help clarify what is going on at low Q2, high Xbj, where people tend to be afraid of higher-twist effects.
When loop diagrams are taken into account with a massive neutrino, a small magnetic moment results (of order 10**-19 mu_Bohr). To observe this magnetic moment, look for an electromagnetic contribution to NC elastic scattering, which can be recognized by its shape as a function of y. It peaks at low y = T/Enu.
Recent limits from LSND are at the 10**-10 level, from about 200 nue-e scattering events. SUSY and extra dimensions could raise the expected mag. moment to 10**-14. MiniBoone could accumulate 100 events in 1-2 years. If the proton driver is upgraded, this yield could increase to, say, 300 events. Perhaps this would correspond to an interesting improvement over LSND. We need to see how these events would look in the miniBoone detector, using the energy-angle correlation as a signature.