Minutes from February 15 meeting

Fritz DeJongh
There is a link from this page discussing cp violation at homestake distances. For comparison, there are also plots for MINOS off-axis distances.

Mark Messier
These are plots related to the beam momentum. Simple summary: if you're worried about nue background lowering the beam momentum won't help. If you're worried about HE tails there may be something to gain. Total rates are roughly prop. to the beam momentum, so if the rep. rate has to increase at least proportionally to avoid losing rate. (Ie. if you drop the momentum by a factor of 2 the rep rate needs to increase by about a factor of 2).
> There are a lot of plots which people can look at on their own. I would only cover a few during a talk.
p1: on-axis LE rates p=120,80,40 GeV
p2: on-axis LE rates relative to p=120 GeV
p3: on-axis LE rates as a function of P_beam (E>6, E<6 GeV)
p4: on-axis LE rates (numu and nue+nubar) for p=120,80,40 GeV
p5: on-axis (nue+nuebar)/numu for p=120,80,40 GeV - roughly no change...
p 6-10: above plots repeated for off-axis LE beam
p11-15: above plots repeated for ME on axis beam
P16-20: aboce plots repeated for ME off axis beam

These are plots related to where to put a near detector to make the numu and nue spectra as close as they can be to the far rates.

For most of the plots the top left is event rates at near, top right is event rates at the far. Bottom plot is the F/N ratio in units of the best fit to the F/N ratio in the 5-10 GeV energy range. The value is given on the plot. The idea was to scale the F/N ratio so that one could look at percent variations as a function of energy. I repeat these plots for different distance between 1 and 3 km (given in the title in the plot). 3 km pushes us to the edge of the FNAL site. Basic conclusion is that anything between 2-3 km is OK, farther being slightly better. p1-6: numu LE off axis beam, z=1,3 km
p7-12: numu ME off axis beam, z=1,3 km
p13: summary of p-p variation in F/N ratio for numu events as a function of ND distance.
p14-19: nue+nuebar LE off axis beam z=1,3 km
p20-25: nue+nuebar ME off axis beam z=1,3 km
p26: summary of p-p variation in F/N ratio for nue events as a function of ND distance.

Plot which shows something we were discussing in an earlier meeting: what happens to the nu_e flux as you go farther and farther off axis?
Nue background in NUMI off-axis beam as function of off axis distance (from Adam Para). The shaded region is the background from kaon decays, and the other region is the total nue_background. I'm pretty sure the units on the vertical axis are: number of events per kton-year per half GeV bin for nominal NUMI ME running. (i.e. if there are about 60 events/kton-yr over a 1GeV bin at 10km off axis, and the nue background is 0.5% then that means there would be 0.3 Events or 0.15 Events in a half-gev bin.)
http://arXiv.org/abs/hep-ph/0108085 Exploring Neutrino Mixing with Low Energy Superbeams by Hisakazu Minakata, Hiroshi Nunokawa, very interesting article showing numu to nue and CP congugate probabilities vs delta for different baselines and energies!
Deborah Harris
Last modified: Thu Feb 14 16:54:40 CST 2002