Transcript PEANUT meeting summary @ Fermilab
Status report of the PEANUT analysis
Giovanni De Lellis
Collaboration Meeting, June 5th 2007, Maiori 1
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
2
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 A procedure to identify single-track events • At least 5 base-tracks • The track with UP > 3 and DOWN < 4 •Track confirmed by SFT detectors 3 For example: UP=4 and DOWN = 2
Neutrino event identification
Single track events •12563 made of more than 4 base-tracks Multiple track events • 4606 vertices reconstructed •252 confirmed by SFT •23 with UP > 3 •24 with all tracks forward and confirmed by SFT •7 pass the “ z versus IP” cut Identification of 30 neutrino interactions in the fiducial volume Neutrino interaction rate in an iron target exposed to NuMI in the near hall
(2 * 10 5 ) / (year * ton)
This value (increased by 8%) accounts for the lead target 54 ± 7 neutrino interactions expected in the analyzed volume N mes / e total = 56 ± 10 neutrino interactions estimated from the 4
dz m m 335 335 335 1635 1635 1635 1635 1635 1635 2947 2947 2947 ip ( m m) 0.9
0.3
0.9
12.2
5.4
6.4
5.5
9.4
6.1
19.3
14.5
25.6
tx mrad -76 -67 -48 -143 -115 8 -13 -123 -60 -70 -148 -129 ty mrad 130 16 77 216 300 173 150 171 184 80 228 180
12 tracks (8 primary)
• 9 vertices with multiplicity 3 • 1 vertex with multiplicity 9 • 1 vertex with multiplicity 12 Electron pairs Open angle for 2 track vertices Electron pair signal 5
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: 78088 • Tracks with nseg>3 and one base-track on PL1 or PL2: 13290 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) Single-prong sample Multi-prong sample 29 VTX 8 created Inside 20 Passing 1 Upstream 1 ° wall 291 56 Created Inside 221 Passing-Through 14 Upstream of 1st wall UP>3 6 28 out of 56 events
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
Total Scan (ongoing) BL092: General Scanning of Plates 1 and 2 7
“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 SFT Class Passing Created Upstream Total Inside Total Scan passing 33 16 5 54 Not. Rec 33 17 5 55 Stop 1-prong Stop Multi-prong Stop out Vol. 138 5 8 49 3 1 15 3 0 202 11 9 8 331 9 ~ 4.6 m m ~ 8 m m ~ 2.4 mrad ~ 5 mrad scan-back predictions: 217 pass-through tracks 134 (maxplate >= 35) stopping points 83 -------> only 6/83 confirmed manually (up to plate 37) 10 8 263 SFT matching tracks followed in the brick 120 Stopping Points Total scan 5 plates upstream & 3 downstream 6 Fake Stops 8 Confirm Stops 1 Two prong 105 Not found 11 Total-Scan analysis in Salerno (BL081 and BL082) Outcome of Scan-back + Manual checks Brick BL081 BL082 Scanback paths 297 383 Stops 45 82 Stop 21 29 Pass 10 40 Scatter Vacuum channel 5 8 0 7 EdgeOut 1 4 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 + 1+1 plates for Virtual erasing Preliminary reconstructions available (using 10 plates) Run 47 Event 189037 – stop at plate 12 V4 event in the emulsion 6 SFT tracks reconstructed Skewed view Red: Scan-back Iris: Total-Scan 12 No match from non-scan-back tracks TotalScan samples from BL081 “Scattering event” Run 47 Event 89037 – stop at plate 14 Prongs 1 2 3 4 Total Event Count 10 2 1 1 14 Skewed view Red: Scan-back Iris: Total-Scan Type SB stop TS scatter SB stop Fail. align. (bad data quality near vacuum channel) Event Count 5 2 Manual Check pass TS stop Total 7 14 SFT: 0.073, -0.094, nhits = 12 SB start/stop: 0.106, -0.084 / 0.124, -0.088 TS + AW Rec: 0.098, -0.079 D/ 0.075, -0.092 U Scattering classification possibly due to local slope tilting Scan-back and total scan in Naples 273 predictions selected by a 3 cut in position and angle w.r.t SFT: 198 passing through and 75 stopping (no hit upstream) 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 Stop Confirmed • 1 multi-prong vertex confirmed in the passing through SFT sample Neutrino interaction occurred 10 m m inside the lead plate Manual check information in the transverse plane 1 8 MIP 4 nuclear fragments 8 2 3 6 7 4 5 Track angles 1: 0.078 0.480 2: 0.089 -0.040 3: 0.146 -0.241 4: 0.260 -0.150 5: 0.423 -0.249 6: -0.360 -0.470 7: -0.045 -0.360 8: -0.017 -0.083 Analysis of the 8 stopping points (stopping also according to the SFT) 1 vertex (multiplicity 2) found All of them (8) confirmed in total scan analysis • 5 vertices with multiplicity 1 • 3 vertices with multiplicity 2 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 20000 15000 10000 5000 0 1月1日 1月16日 1月31日 2月15日 日付 Start : 2006 12/23 3月2日 3月17日 date 4月1日 Cosmic-Ray (tan q <=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 Measurement @Flab with emulsion vertical - 0.013 /min/cm 2 horizontal - 0.19 /min/cm 2 One brick completed 10000cm ２ = 1m 2 ／ ／ １ month 1 month 17 18 1ry VTX pi0 1ry electron candidate shower 19 • • • • • Target region : 61 of 500 micron SUS304. Radiator region: 15 1mm lead. Film +film+ (Fe + film)*61 + (Pb + film + film)*15 0.5*61 + 1.0*15 + 0.288*93 = 72.25mm Radiation length = 1.79+2.68 = 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 events 10K 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 – 20 move after this shutdown for MINERvA or LAr setting up . • 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 213-prong VTX with SFT matching
Scan-back at LNGS
Scan-Back in Neuchatel
Scanning status at Nagoya
Shower search candidate in Nagoya
Nu-e int candidate
Brick configuration and schedule for the Run2
Summary of the ongoing analysis