1 Status report of the PEANUT analysis Giovanni De Lellis Collaboration Meeting, June 5th 2007, Maiori

2 Analysis schema Two analysis streams –SFT driven scan-back, i.e. 2 most downstream films are aligned and the coincidence is matched with the SFT, only matched tracks are followed up –General scanning on a full (large) surface of all films, reconstruct the vertices and match the SFT at the end Standardized analysis to get physics results, from SFT predictions to the analysis cuts

3 IP 90 (m m) General scanning: a procedure to identify multi-track neutrino events optimized with the MC simulation Topological cuts on reconstructed vertices: Impact Parameter, IP < 50 µm and track-vertex longitudinal distance,  z < 3000 µm All tracks downstream of the vertex At least one track confirmed by SFT detector  z-versus-IP bi-dimensional cut as in previous slide At least 5 base-tracks The track with UP > 3 and DOWN < 4 Track confirmed by SFT detectors A procedure to identify single-track events For example: UP=4 and DOWN = 2

4 Neutrino event identification 4606 vertices reconstructed 24 with all tracks forward and confirmed by SFT 7 pass the “  z versus IP” cut made of more than 4 base-tracks 252 confirmed by SFT 23 with UP > 3 Identification of 30 neutrino interactions in the fiducial volume Single track eventsMultiple track events Neutrino interaction rate in an iron target exposed to NuMI in the near hall (2 * 10 5 ) / (year * ton) 54 ± 7 neutrino interactions expected in the analyzed volume N mes /  total = 56 ± 10 neutrino interactions estimated from the This value (increased by 8%) accounts for the lead target

5 Electron pairs dz  mip (  m) tx mradty mrad vertices with multiplicity 3 1 vertex with multiplicity 9 1 vertex with multiplicity tracks (8 primary) Open angle for 2 track vertices Electron pair signal

6 Unbiased analysis in Bologna After fine alignment, tracks are searched for in the volume to recover the broken tracks at the boundaries of the smaller volumes Total number of reconstructed volume tracks: Tracks with nseg>3 and one base-track on PL1 or PL2: volume tracks Alignment between emulsion and SFT (3667 SFT tracks) performed with longitudinal offset correction  1341 matches Brick with 12h cosmic-ray exposure (background rejection under evaluation) 8 created Inside 20 Passing 1 Upstream 1° wall 29 VTX 56 Created Inside 221 Passing-Through 14 Upstream of 1st wall Multi-prong sample UP>3  28 out of 56 events 291 Single-prong sample

7 Scan-back in Bern (SFT predictions from DB) Current Status: BL090: General Scanning of Plates 1 and 2 Match with SFT -> 306 matches found Scan Back -> 94 stopping points 2<emulsion plate<56 Total Scan (ongoing) BL092: General Scanning of Plates 1 and 2

8 “Virtual” scan-back in Bologna SFT selected from DB, match procedure: 607 SFT-PL1-PL2 matched tracks Scan-back is performed and 420 stopping points are identified (too large background) Total-scan performed around 420 stopping points +5 plates upstream -5 plates downstream area: 5x5 mm2 Stopping point in the range 6<PL<53  331 tracks selected Events by SFT classification: SFT Class PassingCreated Inside UpstreamTotal passing Not. Rec Stop 1-prong Stop Multi-prong53311 Stop out Vol Total Scan

9 3-prong VTX with SFT matching

10 8 scan-back predictions: 217 pass-through tracks 134 (maxplate >= 35) stopping points > only 6/83 confirmed manually (up to plate 37) Scan-back at LNGS  ~ 5 mrad  ~ 8  m  ~ 2.4 mrad  ~ 4.6  m

11 Scan-Back in Neuchatel 263 SFT matching tracks followed in the brick New ScanBack 120 Stopping Points 6 Fake Stops 8 Confirm Stops 1 Two prong 105 Not found Total scan 5 plates upstream & 3 downstream

12 Total-Scan analysis in Salerno (BL081 and BL082) Outcome of Scan-back + Manual checks BrickScanback paths StopsStopPassScatterVacuum channel EdgeOut BL BL Efficiency problems on many plates Unbiased Total-Scan to check both Scan-back and Manual checks: data collected around all stopping points in 5×5mm 2 ×(5+5 plates) 5+5 plates = 4+4 plates for reconstruction plates for Virtual erasing Preliminary reconstructions available (using 10 plates) Skewed view Red: Scan-back Iris: Total-Scan Run 47 Event – stop at plate 12 V4 event in the emulsion 6 SFT tracks reconstructed No match from non-scan-back tracks

13 TotalScan samples from BL081 “Scattering event” Run 47 Event – stop at plate 14 Skewed view Red: Scan-back Iris: Total-Scan SFT: 0.073, , nhits = 12 SB start/stop: 0.106, / 0.124, TS +  Rec: 0.098, D/ 0.075, U Scattering classification possibly due to local slope tilting ProngsEvent Count Total14 TypeEvent Count SB stop  TS scatter 5 SB stop  Fail. align. (bad data quality near vacuum channel) 2 Manual Check pass  TS stop 7 Total14

Scan-back and total scan in Naples Total scan performed for the first 22 stopping points 5*5 mm 2 area * 8 films (3 upstream of the stopping point, 4 downstream) -14 passing through SFT tracks - 8 stopping SFT tracks 1 multi-prong vertex confirmed in the passing through SFT sample Stop Confirmed 273 predictions selected by a 3  cut in position and angle w.r.t SFT: 198 passing through and 75 stopping (no hit upstream)

Neutrino interaction occurred 10  m inside the lead plate Track angles 1: : : : : : : : MIP 4 nuclear fragments Manual check information in the transverse plane

Analysis of the 8 stopping points (stopping also according to the SFT) All of them (8) confirmed in total scan analysis 5 vertices with multiplicity 1 3 vertices with multiplicity 2 1 vertex (multiplicity 2) found 67 new stopping points have been identified 45 out of 67 are passing through SFT 3D track 22 out of 67 are stopping SFT 3D tracks

17 Scanning status at Nagoya 10000cm ２ ／ １ month = 1m 2 ／ 1 month Total Scanning Area (cm 2 ) date Start : /23 One brick completed Cosmic-Ray (tan  <=0.4) Brick Assembly 13m(horizontal)0.19x13x100 = 247 1h30m(vertical)0.013x90x100 = 117 De-pack ~20m(horizontal)0.19x20x100 = 380 max~5h(vertical)0.013x300x100 = 390 Under Ground(-105m) 97.39day x ( surface x ~1/100 ) * Flux with emulsion vertical /min/cm 2 horizontal /min/cm 2

18 Shower search candidate in Nagoya

19 Nu-e int candidate pi0 1ry electron candidate shower 1ry VTX

20 Brick configuration and schedule for the Run2 Target region : 61 of 500 micron SUS304. Radiator region: 15 1mm lead. Film +film+ (Fe + film)*61 + (Pb + film + film)*15 0.5* * *93 = 72.25mm Radiation length = = 4.47 X0 5.09kg (2.97kg+2.12kg) 9.9K+7.0K int. expected for 48 bricks 100days Shutdown foreseen on Aug 6 th  60days exposure  10K events Two weeks for run setup –Start setup at Fermilab on May 31 st (2 European and 4 Japanese) Darkroom setup at MINOS Service Building –Brick assembling Started the day before yesterday NuMI shutdown on Aug 6 th –move after this shutdown for MINERvA or LAr setting up.

21 Summary of the ongoing analysis 22 bricks under analysis in Europe Nagoya is focused on general scanning (1 brick analysis ongoing) General scanning: Naples (30 located events), Bari (10 2-track VTX) and Bologna (8+28)  ~ 200 events (the SFT bias removable and useful to cross-check the scan-back)  request to provide a summary of the data analyzed (multiplicity and SFT matching) Scan-back and total scan performed in a few labs and the confirmed stopping points are: Salerno (50), Naples (25)  a few hundred located events expected within Summer Large effort in the optimization of the strategy and tuning of parameters Non-linear extrapolation to the expected events The connection between PEANUT and MINOS to be provided (US) MonteCarlo simulation improved with SFT hit simulation Multiplicity study and measurement of 3 components (DIS, QE and RES) feasible with RUN1 Electron neutrino component in RUN2