1. Lepton Flavor violation study In Muon-neutrino to Tau direct coupling Very preliminary estimations Nakamura M. August 2009

2. Aim Investigate the lepton flavor violation through direct coupling of Muon neutrino to Tau lepton 10^-7??? Emulsion experiment in order to detect Tau lepton produced in neutrino interactions. =>x10CHORUS ??? 1.Background (1) prompt Tau-neutrino in CHORUS (2) Charm in Antineutrino events 2.Scale up possibility (1) The detector set-up (2) Emulsion Read-out

3. Prompt Tau neutrino In CHORUS, Expectation of prompt tau neutrino was from 10^-7 to 10^-6. Proton beam energy: Charm CERN WANF 450GeV ~30 microbarn FNAL NuMI 120GeV. 5 microbarn Probably Better suppression in NuMI CERN WANF :CHORUS

4. Charm in anti-neutrino events Expected charm in anti-neutrino events relative to muon neutrino events Anitnu/nu Charm Semi-muonic Primary Muon missing 0.05 × 0.05 ×0.1 ×0.1 ＝ 2.5×10 ＾ -5 How ｔ o suppress charm ？ If you need to suppress this to 10^-7 then rejection power should be 250. Seeds?: Improvement of Muon tagging efficiency 0.9  0.99??? X10 Kinematical cuts : Phi distribution? Factor? Charm reconstruction in semi muonic decay mode? Factor?

5. Emulsion tech. Scale up? CHORUS OPERA Current exp. Target Mass 800kg 1300ton 10ton? Gel Mass 800kg 30ton 1~10 ton? # of Films 600 9.3M 100K~10K Price: \200M \2G Current Emulsion supplier: Fuji (Japan) Slavich (Russia) Scale down from OPERA

6. Scanning tech. Scale up? CHORUS OPERA Planning exp. Scan Area 1 m^2/4year 100m^2/year 20m^2??? # of events 500K/4year 4K/year 10M # of Films 600 9.3M 100K~10K System NTS / UTS SUTS SUTS Speed ~1cm2/h 100cm2/h 100cm2/h LOAD 5 Years 1 Year 3 months We are planning to develop much faster system ~5000cm2/h (SQTS) for dark matter, double beta experiment and Muon radiography.

7. By-product? Charm Physics?? D0-D0bar Oscillation? Charmed penta-quark study ? Charmed hadron mean free path ? Charmed Nucleus study? …..