Reconstruction of neutrino interactions in PEANUT in general

scanning (unbiased) mode

Giovanni De Lellis on behalf of Andrea Russo

Naples University

PEANUT detector

BL033

Neutrino beam and Cosmic ray exposure

Beam Position Start End Duration (day)

NEUTRINO 141 2005/10/20 16:25 2005/11/07 09:20 17.75

COSMIC RAYS 2005/11/07 09:40 2005/11/07 11:40 0.08 (2h)

Scanning areasAll 57 plateshave been

general scanned:

5.55 x 4.30 cm^2 = 23.9cm^2

General scanning mode

Measured density of aligned base-tracks: 4 base-track / mm2 (transportation order)

0.7 base-track / mm2 (assembly order)

38 plateshave been

general scanned:

11.1 x 4.30 cm^2 = 47.8 cm^2

PEANUT emulsionsTransportation order Beam exposure

~ 8 m

Track reconstruction

=13 mrad

Micro-track angular resolution

Position and angular resolution in the plate to plate alignmentConsecutive base-track accuracy

~ 5 mrad

= 0.7m = 3mrad

Base-track resolution: spatial and angular differencebetween a base-track and the corresponding volume track

Density of aligned base-tracks ~ 4/ mm2

Track reconstruction in transportation order

Characterization of the tracks in transportation order

Due to low momentum protons (~100MeV)

High ionizing power (at least 10 segments in the following plots)

High tracking efficiency

Beam tracksat least 4 segments in the plots shown

NuMI beam peak(x, y-( ~ )50,0 )mrad

MIP particles:<Grain number> ~ 24

Tracking efficiency

Density of aligned base-tracks ~ 0.7 / mm2

Emulsion-SFT matching

yx

tx ty

• x = 1190 m

• y = 1240 m• tx = 5 mrad• ty = 8 mrad

Angularmisalignment

Brick rotation

beam

= 24 mrad 2.4 mm

SFT planes

brickz depending on the position

z

Top View

Emulsion-SFT matching after z correction• x = 605 m

• y = 443 m• tx = 6 mrad• ty = 5 mrad

Impact parameterand z distribution

track to vertex longitudinal distance

IP z

~ 60% up to 10 µm

Neutrino event identification

62278 volume tracks reconstructed

• 2995 vertices reconstructed

•658 with all forward tracks

•17 confirmed by SFT (154 “z versus IP” )

•7 pass the “z versus IP” cut

•11765 made of more than 4 base-tracks

•171 confirmed by SFT

•17 with UP > 3

Identification of 24 neutrino interactions in the fiducial volume

Single track events Multiple track events

MC Multiplicity

“High” multiplicity events not matching the SFTdz (m) ip (m)

697 1.2

697 0.4

1988 8.2

dz (m) ip (m)

912 2.4

2203 0.8

912 2.3

dz (m) ip (m)

941 3.4

2226 10.0

941 3.9

tx (mrad) ty (mrad)

-26 244

156 -126

-99 379

tx (mrad) ty (mrad)

394 -231

-642 -2

355 -402

tx (mrad) ty (mrad)

-381 -380

116 -131

-43 -716

“High” multiplicity events not matching the SFT

dz (m) ip (m)

2041 18.1

2041 20.1

2041 22.1

dz (m) ip (m)

1318 2.9

1318 4.2

1318 4.9

tx (mrad) ty (mrad)

67 231

66 -116

-134 51

tx (mrad) ty (mrad)

-39 88

-101 129

-44 93

“High” multiplicity events not matching the SFT

tx (mrad) ty (mrad)

234 32

84 -169

269 -316

-131 198

Dz (m) ip (m)

1040 6.0

1040 4.1

1040 5.5

2358 43.3

dz (m) ip (m)

582 0.3

582 0.7

582 1.0

tx (mrad) ty (mrad)

90 -257

-14 41

82 229

“High” multiplicity events not matching the SFTtx(mrad) ty(mrad)

23 -191

-48 148

264 -121

193 188

-33 134

-204 72

-180 -303

2 -388

162 42

dz(m) ip(m)

1699 10.3

1699 10.9

1699 8.1

1699 5.0

1699 5.1

1699 3.9

1699 6.6

1699 23.0

1699 15.4

Preliminary Multiplicity 9!

Expected number of events in the brick

Beam Begin End Duration (days)

NEUTRINO 2005/10/20 16:25 2005/11/07 09:20 17.75

COSMIC 2005/11/07 09:40 2005/11/07 11:40 0.08

Neutrino interaction ratein an iron target exposed to NuMI

in the near hall(2 * 105) / (year * ton)

43 ± 7 neutrino interactions expected in the analyzed volume

Nmes/total = 44 ± 9 neutrino interactions estimated from the 24 observed events after efficiency correction

This value (increased by 8%) accounts for the lead target

Conclusions• A volume of 413 cm3 (58% of the brick volume) was

general scanned in one PEANUT brick• Detailed single brick Monte Carlo simulation of PEANUT

used to define a procedure to identify neutrino interactions• 24 neutrino interactions with SFT matching have been

identified in the volume• After the efficiency correction, we estimate (44 ± 9)

neutrino interactions happening in the volume• Good agreement with the number of expected events (43 ±

7) computed from the flux• 8 events with larger multiplicity found without any match

with the SFT (6 with 3 tracks, 1 with 4 and 1 with 9 tracks)