1. baselines, plan B's and conclusions A. low energy option (300-500 MeV e.g. CERN from 3.5 GeV (optimal) proton superbeam and 'normal gamma 100-150' beta beam. [gamma 100 has optimal baseline of 200 -70 + 50 km gamma 150 " 300 km] Water Cherenkov is the baseline ------------------------------- 20% coverage of the 20" phototubes (or equivalent measure of photon detection) is estimated to be sufficient for the neutrino beam application Higher coverage driven by astrophysical oor proton decay applications Water purity and composition are critical issues when looking for very low mu--> e contamination. Present experiment (K2K) has not pushed the analysis to the limit (no statistics) e--> mu is the critical parameter for the beta beam. Then comes pi-> mu critically energy dependent. (this is intrinsic -- requires a migration matrix -- requires critically a near detector for determination of pion background) mass is about 440 kton fiducial (MEMPHYS project) The liquid argon detector ------------------------- has lower mass (100kton is considered) (what is the fid mass?) which is not compensated by the improved efficiency or background rejection. The pi- and mu- are captured most of the time (73% in argon vs 22% in water for muons) so this handle against background is not available. Nuclear effects are likely to be worst than in water. Cross-section issues -------------------- Double ratio is affected at the level of 6% (at 250 MeV) by the interplay of muon mass and nuclear effects. The systematic uncertainty on this number is not evaluated yet, but difference between Fermi Gas and spectral function calculations is 2%. This decreases fast with increasing energy. Below 250 MeV calculation is uncertain due to nuclear binding energy. The issue of pion production and nuclear reabsorbtion is next in the todo list. fiducial volume error will be smaller will also improve with better timing of phototubes and larger volume to skin ration of larger detector. design of close detector ------------------------ for nu-es the beta beam as it is is wonderful because flux will be known to 0.5% precision. Some straightening up in the beta decay etc need to be done. nu-e and nu-mu cross-sections are needed. Monochromatic K-capture beam is very useful to test the modeling of nuclear effects, but is not strictly necessary to carry out the experiment. near detector design for the low energy options is virgin territory, but will be needed if experiment is to be credible. -- Water Cherenkov? -- other better detector to measure e.g. electron scattering events and get absolute cross-sections in either polarity beams. Is the pi decay superbeam necessary? certainly adds considerable statistical power. Everybody would like to have both. Other issues ------------ we would like to see the T2KK comparison B. middle energy option (i.e. beta-beam at super SPS or Tevatron gamma = 350) E ~ 1.5 GeV studies: -- water Cherenkov (JJ. Gomez Cadenas et al) -- Terranova et all (Iron non magnetic calorimeter) -- fully active scintillator (NOvA like) study by Lindner -- liquid argon? Conclusions? is there a baseline detector? near detector station similar to previous one. Nuclear effects likely to be marginal. issues: Water Cherenkov is working in multiring region, where total energy is not easy to reconstruct... migration matrix discussion. request more info. not a very clear domain. C. Neutrino factory (E max = 20-30 GeV) requires magnetic field Baseline is the magnetized iron detector ---------------------------------------- Nelson has considered the possibility of a 100kton mass detector (NOvA+MINOS techniques) cost estimate 200M$ 4cm iron+3cm scintillator Cervera has studied the parametric performance of such a detector typical resolution needed is 1cm to match B field. INcresng B field wrt MINOS would improve resolution accordingly note that the analysis should be done on a binned basis (at list in Pmu) to take advantage of the lower energy bins at high values of theta13. This should be considered high priority. Cervera has all information needed. Cut on muon energy to be made on the basis of visible hadron energy (like in CDHS) more complete simulation (level of sophistication to be defined) will be needed. (Pietro Chimenti expressed interest) avenues to be pursued: smaller density and air gaps to allow both position and angle measurements. test to be made: evaluate exactly the resolution and sign confusion with test beam. (15 GeV muons) other detectors --------------- magnetizing other fully active detectors (scintillator, Liquid Argon, ECC) seems extremely expensive. (Strolin, Bross) typical cost estimates varies between 14-70 M$ for a 0.4 T magnet 15x15x15 m3 = 3.3 kton of density one material. SC is necessary. The driving cost element is the cost of vaccum vessel for the cryostat using SC cryogenics. High Tc could be a way out, at the moment is is WAY too expensive and not feasible but progress seems fast. liquid argon group suggests savings by incorporating a high Tc magnet in the liquid argon cryostat. No cost estimate given. A more careful study is needed on a more specific case. Potential gain is the measurement of the -- tau channel (but could this be done with a non-magnetic emulsion detector followed or surrounded by the LMD? ) The exact setup -- electron channel but here one has to be careful to really get up to the first maximum electrons (6 GeV at 3000 km) Emulsion Cloud Chamber detector (ECC) ------------------------------------- Follows on OPERA technology Potential gain is the measurement of the -- tau channel This could be done with a non-magnetic emulsion detector followed or surrounded by the LMD. The exact setup needs to be worked out. Nice simulation work has been done. 2. R&D plans 3. ISS meeting in Irvine