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Bern Scanning Laboratory

Bern Scanning Laboratory. Hunting muonless interactions. NC event 179312944. muonless event 179312944. 179312944;391;neut;2007-10-06 11:46:34;1;1;W25;R13;C25; 01011847 179312944;391;neut;2007-10-06 11:46:34;1;1;W25;R13;C24; 01011845

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Bern Scanning Laboratory

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  1. Bern Scanning Laboratory Hunting muonless interactions... I. Kreslo, LHEP, Bern

  2. I. Kreslo, LHEP, Bern

  3. NC event 179312944 I. Kreslo, LHEP, Bern

  4. muonless event 179312944 179312944;391;neut;2007-10-06 11:46:34;1;1;W25;R13;C25; 01011847 179312944;391;neut;2007-10-06 11:46:34;1;1;W25;R13;C24; 01011845 179312944;391;neut;2007-10-06 11:46:34;1;1;W25;R13;C26; 01011669 179312944;391;neut;2007-10-06 11:46:34;1;1;W25;R14;C25; 01012865 179312944;391;neut;2007-10-06 11:46:34;1;1;W25;R12;C25; 01008954 3 Bricks are developed I. Kreslo, LHEP, Bern

  5. CS predictions First step – standart: 6 prediction are found in CSD, - not found in any of three bricks. Need for more sophisticated approach… I. Kreslo, LHEP, Bern

  6. Veto alignment (pl 57 – veto 58) Two alignments !! Veto was moved during exposure. 500 microns Is the situation with CSD the same? If yes => Search area=1x1mm I. Kreslo, LHEP, Bern

  7. Veto dublet deformations Is the situation with CSD the same? If yes => Angular tolerance ~30 mrad. I. Kreslo, LHEP, Bern

  8. Pl 57 deformations Z Distance CSD – P57 Error up to 300 microns I. Kreslo, LHEP, Bern

  9. Full area scan Emulsions 57,56,55 + CS0,CS1 Full area scan Total number of tracks not found in CSD: about 1300! (No angular constraints) IP=300 microns, >3-fold-pre-vertexing “Pre-vertexing” allows to limit number of SB pathes to 75 (~5%) I. Kreslo, LHEP, Bern

  10. Scanback of pre-vertexed tracks Initially 75 tracks, 32 stops, 28 stops to analyse (pl 3-53), 43 passing No converging stopping tracks….. I. Kreslo, LHEP, Bern

  11. Totalscan around stops I. Kreslo, LHEP, Bern

  12. Visual check : SB path 4248 Smth. interesting SB track I. Kreslo, LHEP, Bern

  13. Vertex found Good vertex ! But there is a sign of incoming track (see prev. slide) I. Kreslo, LHEP, Bern

  14. Volume scan around vertex 577 748 1211 2938 450 Tracks are visible in veto => This is NOT a neutrino event, but HE cosmics reaction I. Kreslo, LHEP, Bern

  15. After scanback of ~1300 tracks two interesting vertices found I. Kreslo, LHEP, Bern

  16. After scanback of ~1300 tracks two interesting vertices found I. Kreslo, LHEP, Bern

  17. NC candidate : volume scanNo additional tracks related to vertex are found 2x2cm x 9 plates I. Kreslo, LHEP, Bern

  18. Check presence of tracks in VD (Veto Dublet) Confirmed: NOT in VETO ! I. Kreslo, LHEP, Bern

  19. NC candidate 1 : detector view Hadronic shower CG fit I. Kreslo, LHEP, Bern

  20. NC candidate 1 Hits in TT correspond to possible interaction => Likely NC event I. Kreslo, LHEP, Bern

  21. NC candidate 2 : detector view I. Kreslo, LHEP, Bern

  22. NC candidate 2 No hits, high IP => unlikely. I. Kreslo, LHEP, Bern

  23. NC candidates 1,2 Checked presence in the CSD – not found…. . I. Kreslo, LHEP, Bern

  24. Effect on CR density discussion... If no CSD predictions found for one of reasons, then: 1300 tracks to follow => Not possible in 24h/brick Strong selection (maybe few% of total) still leads to fake events (3) Reduction of CR density by factor 5 would be very desirable… I. Kreslo, LHEP, Bern

  25. Predictions from LNGS => Low momentum shower? • Volume scan 2x2cm 57 plates • VTX reconstruction with IP<50 microns, min Nseg=2: • 5189 2-prong vertices (!) • 86 3-prong (too many to check) (left as the last chance) • 7 4-prong (incoming tracks -> rejected) • 1 5-prong (all 2 seg tracks, high IP – rejected) • VTX reconstruction with IP<50 microns, min Nseg=5: • 13 2-prong vertices, 2 correlated with prediction: • #1 incoming track reconstructed with the gap of 4 plates, • #2 incoming track out of volume (re-scanned bigger volume) I. Kreslo, LHEP, Bern

  26. Summary on the event search • Standart prediction search gave no consistent tracks in pl 57,56. • Volume scan around predicted tracks => Some candidates, rejected for various reasons. • Fullarea scan with Veto-in cosmics: 1300 tracks to consider • Pre-vertexing procedure applied, no converging tracks, however 28 stops. TotalScan is done visual checks – done. 7-prong CR interaction found, rehearsal of vertex analisys is done on this interaction, all scanning tasks in fully automatic mode. • Scanback of all ~1300 tracks from pl57-55, not found in Veto is complete • One vertex from external interaction is found and confirmed : • - NOT in VETO • - YES in TT • - NOT in CSD • Extract upstream brick?! Reasonable to say Yes. • Event is not found, but the strategy starts to develop. I. Kreslo, LHEP, Bern

  27. Prediction location 1 PRONGS ? >1 Location in pl 57 DX=1mm NO FOUND ? YES Visual check NO CONFIRMED ? YES Scanback with IC at CG of cluster NO STOPS ? YES Scanforth to VETO YES FOUND IN VD ? NO Totalscan 5x5mmx10pl I. Kreslo, LHEP, Bern

  28. Scenario for muonless event location NO CS TRACKS ? YES Prediction location NO Located ? YES Volume scan 2x2cm 57pl + VETO around first TT cluster CG Find all alignments Erase tracks, present in VD Pre-vertexing 3 prong, IP<300microns Prediction location e- Shower search In a volume (+VD!) NO Located ? YES I. Kreslo, LHEP, Bern

  29. Shower confirmation Check BT in VETO YES FOUND IN VD ? NO Check BT in CSD ? NO FOUND IN VD ? YES I. Kreslo, LHEP, Bern

  30. Muonless event location strategy First picture of the algorithm becomes clear Worked well for two events so far : One CR and one neutrino (see next talk by C.Pistillo) Very time consuming, but very precious (νμCC events,Tau-> e, Tau-h channels) => firther optimisation (minimisation) is crucial. I. Kreslo, LHEP, Bern

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