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
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IP90
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
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Neutrino event identification
• 4606 vertices reconstructed
•24 with all tracks forward and confirmed by SFT
•7 pass the “z versus IP” cut
•12563 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 events Multiple track events
Neutrino interaction ratein an iron target exposed to NuMI
in the near hall
(2 * 105) / (year * ton)
54 ± 7 neutrino interactions expected in the analyzed volume
Nmes/total = 56 ± 10 neutrino interactions estimated from the
This value (increased by 8%) accounts for the lead target
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Electron pairs
dz m ip (m)
335 0.9
335 0.3
335 0.9
1635 12.2
1635 5.4
1635 6.4
1635 5.5
1635 9.4
1635 6.1
2947 19.3
2947 14.5
2947 25.6
tx mrad ty mrad
-76 130
-67 16
-48 77
-143 216
-115 300
8 173
-13 150
-123 171
-60 184
-70 80
-148 228
-129 180
• 9 vertices with multiplicity 3• 1 vertex with multiplicity 9• 1 vertex with multiplicity 12
12 tracks (8 primary)
Open angle for 2 track verticesElectron pair signal
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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)
8 created Inside20 Passing1 Upstream 1° wall
29 VTX56 Created Inside221 Passing-Through14 Upstream of 1st wall
Multi-prong sample
UP>3 28 out of 56 events
291
Single-prong sample
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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
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“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 downstreamarea: 5x5 mm2
• Stopping point in the range 6<PL<53 331 tracks selected
• Events by SFT classification:SFT Class
Passing Created
Inside
Upstream Total
passing 33 16 5 54
Not. Rec 33 17 5 55
Stop 1-prong 138 49 15 202
Stop Multi-prong 5 3 3 11
Stop out Vol. 8 1 0 9
331
Total Scan
10
8
scan-back predictions: 217pass-through tracks 134 (maxplate >= 35) stopping points 83 -------> only 6/83 confirmed manually (up to plate 37)
Scan-back at LNGS
~ 5 mrad
~ 8 m
~ 2.4 mrad
~ 4.6 m
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Scan-Back in NeuchatelScan-Back in Neuchatel
263 SFT matching tracks followed in the brick
New
Sca
nBac
k
120 Stopping Points
6 Fake Stops8 Confirm Stops
1 Two prong105 Not found
Total scan
5 plates upstream & 3 downstream
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Total-Scan analysis in Salerno (BL081 and BL082)
Outcome of Scan-back + Manual checks
Brick Scanback paths
Stops Stop Pass
Scatter
Vacuum channel
EdgeOut
BL081 297 45 21 10 5 8 1
BL082 383 82 29 40 0 7 4Efficiency problems on many plates
Unbiased Total-Scan to check both Scan-back and Manual checks:data collected around all stopping points in 5×5mm2×(5+5 plates)
5+5 plates = 4+4 plates for reconstruction + 1+1 plates for Virtual erasing
Preliminary reconstructions available (using 10 plates)
Skewed viewRed: Scan-backIris: Total-Scan
Run 47 Event 189037 – stop at plate 12V4 event in the emulsion6 SFT tracks reconstructed
No match from non-scan-back tracks
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TotalScan samples from BL081
“Scattering event” Run 47 Event 89037 – stop at plate 14
Skewed viewRed: Scan-backIris: Total-Scan
SFT: 0.073, -0.094, nhits = 12SB start/stop: 0.106, -0.084 / 0.124, -0.088
TS + Rec: 0.098, -0.079 D/ 0.075, -0.092 UScattering classification possibly due to local slope tilting
Prongs
Event Count
1 10
2 2
3 1
4 1
Total 14
Type Event Count
SB stop TS scatter 5
SB stop Fail. align.(bad data quality near vacuum channel)
2
Manual Check pass TS stop
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Total 14
Scan-back and total scan in Naples
Total scan performed for the first 22 stopping points5*5 mm2 area * 8 films (3 upstream of the stopping point, 4 downstream)
-14 passing through SFT tracks- 8 stopping SFT tracks
•1 multi-prong vertex confirmedin 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 10m inside the lead plate 1
8
6 7
3
4 5
2
Track angles1: 0.078 0.4802: 0.089 -0.0403: 0.146 -0.2414: 0.260 -0.1505: 0.423 -0.2496: -0.360 -0.4707: -0.045 -0.3608: -0.017 -0.083
8 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
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0
5000
10000
15000
20000
1 1月 日 1 16月 日 1 31月 日 2 15月 日 3 2月 日 3 17月 日 4 1月 日日付
cm面
積(
2 )
Scanning status at Nagoya
10000cm 2 / 1 month = 1m2 / 1 month
Tot
al S
cann
ing
Are
a (c
m2 )
dateStart : 2006 12/23
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 Measurement @Flab with emulsionvertical - 0.013 /min/cm2
horizontal - 0.19 /min/cm2
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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*61 + 1.0*15 + 0.288*93 = 72.25mmRadiation length = 1.79+2.68 = 4.47 X05.09kg (2.97kg+2.12kg)9.9K+7.0K int. expected for 48 bricks 100days
• Shutdown foreseen on Aug 6th 60days exposure 10K events
• Two weeks for run setup– Start setup at Fermilab on May 31st (2 European and 4 Jap
anese) • Darkroom setup at MINOS Service Building
– Brick assembling• Started the day before yesterday
• NuMI shutdown on Aug 6th
– move after this shutdown for MINERvA or LAr setting up .
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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) a
nd 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 RE
S) feasible with RUN1• Electron neutrino component in RUN2
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