1. Umut Kose Neutrino interaction location in the OPERA Experiment New Development of Flavor Physics, 10.03.2009, Tennomaru, Gamagori Nagoya University

2. Vertex location method scan back volume scan around VTX prediction point (~1cm*1cm*10plates)‏ VTX located volume scan around stop plate (~1cm*1cm*10plates)‏ direct VTX hunting method scan back location method not found VTX search found partner & parent search CSD found Decay Search

3. 5 mm ECC Brick (57 emulsions + 56 Pb)‏ CS Doublet Scanback location Method 600micron 160micron Track is scanned around prediction point

4. Scanback location Method 5 mm ECC Brick (57 emulsions + 56 Pb)‏ CS Doublet Stopping Plate The vertex is confirmed by scanning a volume around the stopping position; recording all the track segments within a given angular acceptance: NetScan data taking. The fiducial volume is 1cm2x10 films in total.

5. CS-ECC connections

6. 5 mm CS Doublet ECC Brick NetScan Fiducial Volume 1cm 2 x10 plates Direct Vertex Hunting

7. How to analyse ECC data Track segments overlapped At least 2-segment connected tracks Eliminate passing through tracks Reconstruct full vertex topology Offline tracking and vertex reconstruction

8. Summary of events: 147 neutrino interaction vertex is located in ECC bricks 368 ECC arrived 38 in progress VTX located 84 penetrating 101 46 Edge out 14 Stopped in ECC 25 In progress 158 ScanBack 3 Failed 200 84 Direct Vertex 57 VTX located In progress 147 events = 116 CC + 31 NC

9. Position distributions Y (mm)‏ X(mm)‏

10. NC Events CC Events All Events Vertex Plate distributions

11. Multiplicity distributions All Events CC Events NC Events

12. Slope distributions xx yy xx yy Space angle

14. X projection Y projection Z projection   

17. Y projection X projection

18. Summary In total about 500 events (Europe+Japan Scanning centers) located in ECC.. Neutrino location chains from electronic detector to ECC working well.. OPERA neutrino interaction location and tau decay search is going on… The tau decay search will be introduced by the next speaker; Nonoyama…