Umut Kose

Neutrino interaction location in the OPERA

Experiment

New Development of Flavor Physics, 10.03.2009, Tennomaru, Gamagori

Nagoya University

Vertex location method

scan back

volume scanaround VTX prediction point

(~1cm*1cm*10plates)

VTX located

volume scanaround stop plate

(~1cm*1cm*10plates)

direct VTX hunting method scan back location method

not foundVTX search

found

partner & parent search

CSD found

Decay Search

5 mm

ECC Brick (57 emulsions + 56 Pb)

CS Doublet

Scanback location Method

600micron

160

mic

ron

Track is scanned around

prediction point

Scanback location Method

5 mm

ECC Brick (57 emulsions + 56 Pb)

CS Doublet

Stopping Plate

The vertex is confirmed by scanning a volume around the stopping position;

recording all the track segments within a given angular acceptance: NetScan data taking.

The fiducial volume is 1cm2x10 films in total.

CS-ECC connections

5 mm

CS Doublet

ECC Brick

NetScan Fiducial Volume

1cm2x10 plates

Direct Vertex Hunting

How to analyse ECC data

Track segments overlapped

At least 2-segment connected tracks

Eliminate passing through tracks

Reconstruct full vertex topology

Offline tracking and vertex

reconstruction

Summary of events:

147 neutrino interaction vertex is located in ECC bricks147 neutrino interaction vertex is located in ECC bricks

368

ECC arrived

38

in progress

VTX located

84

penetrating

101

46

Edge out

14

Stopped in ECC

25

In progress

158ScanBack

3

Failed

200

84

Direct Vertex

57

VTX located

In progress

147 events = 116 CC + 31 NC

Position distributionsPosition distributions

Y (mm)

X(mm)

NC Events CC Events

All Events

Vertex Plate distributionsVertex Plate distributions

Multiplicity distributionsMultiplicity distributions

All Events

CC Events NC Events

Slope distributionsSlope distributions

x

y

x

y Space angle

X projection

Y projection Z projection

Z projection

Y projection

X projection

Summary

• In total about 500 events (Europe+Japan Scanning centers) located in ECC..

• Neutrino location chains from electronic detector to ECC working well..

• OPERA neutrino interaction location and tau decay search is going on…

• The tau decay search will be introduced by the next speaker; Nonoyama…