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

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

5

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

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3-prong VTX with SFT matching

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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Shower search candidate in Nagoya

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Nu-e int candidate

pi0

1ry electron candidate

shower

1ry VTX

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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