Summary of Nufact-03 Alain Blondel NuFact 03 5th International Workshop on Neutrino Factories & Superbeams Columbia University, New York 5-11 June 2003 Highlights and personnal impressions

Summary of Nufact-03 Alain Blondel first results from miniboone first results from MUSCAT! theta13 prospectives (reactor proposals!) the issue of degeneracies beta beam getting close in performance to neutrino factory?! Nufact: death of bow-tie machine part: MICE strongly recommended – in approval path status of target status of RF cavity studies status of accelerator design FFAG!!!! Cooling ring!!!! to cool or not to cool? cost saving hopes WORLD STUDY III synergies: emphasis on low energy muon and high intensity physics personnal reflexions: Europe’s strengths two avenues for Europe: when should we chose? NUFACT03 Highlights

Summary of Nufact-03 Alain Blondel   peak Miniboone

Summary of Nufact-03 Alain Blondel MUSCAT an important experiment to re-measure multiple scattering for low Z materials (discrepancies between theories and theory vs expt) engineering run 2000… several teething problems 2. new measurements in spring 2003 at Triumf with many improvements (sci-Fi tracker!) 2003 Physics run all went very well –46M events taken; LH2 as well as solid targets –First look at data: very good; Analysis just starting First results: ENG meeting 9 th July (?)

Summary of Nufact-03 Alain Blondel  J Louis  approved (MINOS, OPERA, ICARUS) programme on approval path (J-PARC  SK) will lead to improvement vs CHOOZ by factor 2-3 (MINOS, ICARUS+OPERA with tau optimized beam) by factor 5 specially optimized L.E beam for ICARUS by factor 20 J-PARC  SK what else?

Summary of Nufact-03 Alain Blondel  Superbeam possibilities 1.J-PARC  SK (2008 onwards) J-PARC  HK (1 Mton) will not begin excavation before results from J-PARC  SK are obtained 2011? also hopes to increase intensity from 0.7 MW to 4 MW. 2. Off-axis NUMI beam exists with required flexibility detector design in progress – will lead to a LOI in the fall near detector. (how can this be in time to be competitive???) 2’. CNGT: need beam (not CNGS) and detector. Detector viability? (single wall is ‘technologically risky’) + interesting: what is the physics of an off axis at the second osc. max? - no near detector NB similar idea had been put forward by Susuki in 2000 in an immersed super-tanker. both 2 and 2’ are dedicated detectors that can do nothing else as such. (CNGT could be re-deployed as km 3 detector) 3.BNL  homestake mine 4. SPL + beta beam  Frejus a very serious contender iff beta beam can perform as advertised. (almost a neutrino factory!) ecavation could start in 2008 (better get our act together!) the most consistent scheme for a CERN based effort!  support SPL + propose the Fréjus International Laboratory

Summary of Nufact-03 Alain Blondel NuMI Off-axis Detector Low Z imaging calorimeter: yGlass RPC or yDrift tubes or yLiquid or solid scintillator Electron ID efficiency ~ 40% while keeping NC background below intrinsic e level Well known and understood detector technologies Primarily the engineering challenge of (cheaply) constructing a very massive detector How massive?? 50 kton detector, 5 years run =>  10% measurement if sin 2 2  13 at the CHOOZ limit, or  3  evidence if sin 2 2  13 factor 10 below the CHOOZ limit (normal hierarchy,  =0), or zFactor 20 improvement of the limit Para

Summary of Nufact-03 Alain Blondel NuMI Off-axis 50 kton, 85% eff, 5 years, 4x10 20 pot/y JHF to SK Phase I, 5 years allAfter cutsallAfter cuts   CC (no osc) NC Beam e Signal (  m 2 23 =2.8x 10 -3,      NuMI/JHF) FOM (S/sqrt(B)) Para

Summary of Nufact-03 Alain Blondel Determination of mass hierarchy: complementarity of JHF and NuMI Combination of different baselines: NuMI + JHF extends the range of hierarchy discrimination to much lower mixing angles Minakata,Nunokawa, Parke Para

Summary of Nufact-03 Alain Blondel BNL  Homestake Super Neutrino Beam 2540 km Homestake BNL 28 GeV protons, 1 MW beam power 500 kT Water Cherenkov detector 5e7 sec of running, Conventional Horn based beam Diwan

Summary of Nufact-03 Alain Blondel Advantages of a Very Long Baseline  neutrino oscillations result from the factor sin 2 (  m 32 2 L / 4E) modulating the flux for each flavor (here  disappearance)  the oscillation period is directly proportional to distance and inversely proportional to energy  with a very long baseline actual oscillations are seen in the data as a function of energy  the multiple-node structure of the very long baseline allows the  m 32 2 to be precisely measured by a wavelength rather than an amplitude (reducing systematic errors) Diwan

Summary of Nufact-03 Alain Blondel e Appearance Measurements  a direct measurement of the appearance of   e is important; the VLB method competes well with any proposed super beam concept  for values > 0.01, a measurement of sin 2 2  13 can be made (the current experimental limit is 0.12)  for most of the possible range of sin 2 2  13, a good measurement of  13 and the CP-violation parameter  CP can be made by the VLB experimental method Diwan

Summary of Nufact-03 Alain Blondel e Appearance Measurements (Cont.)  even if sin 2 2  13 = 0, the current best-fit value of  m 21 2 = 7.3x10 -5 induces a e appearance signal  the size of the e appearance signal above background depends on the value of  m 21 2 ; the figure left indicates the range of possible measured values for the e yields above background for various assumptions of the final value of  m 21 2 Diwan

Summary of Nufact-03 Alain Blondel very long baseline proposal (BNL  homestake mine) -- interest: CP violation and sign  m 2 13 from 1st to second peak comparison -- energy dependence helps extracting the physics criticisms: 1.very large mass required to reach decent sensitivity (1/L 2 dependence hurts) 2.possibility of detecting e signal at > 1-2 GeV seriously criticized