OPERA 2008 run: a report from the Swiss scanning lab

Ciro Pistillo

LHEP Bern university

for the Swiss scanning team

OPERA Collaboration meeting Ankara, April 1-4 2009

Status of event location

TOTAL CC NC BLACK CS

Received events

126 105 21 11

Received bricks

127 106 21 11

Valid events

124 105 19 10

Analyzed events

122 103 19 8

Status of event location

TOTAL CC NC BLACK CS

Located in ECC

101 87 14 4

Located in dead

material2 1 1 -

Passing through

7 5 2 1

Analysis completed

110 93 17 4

Connected 115 96 19 5

Pending 12 10 2 3

Scanning now

2 2 - 2

Status of publication

Bricks:

85 / 101 published in central DB

Vertices:

78 / 101 published in central DB

Vertex position

Plate number

Prong multiplicity

TOTAL

CC NC

Impact parameter

IP (not mu) Δz < 1300

IP (mu)

IP < 10 m

IP < 10 m

large angle black tracks

IP (not mu)

Interesting topologies

Event no. 231012915 located in brick 72853

Event no. 228197639 located in brick 14653 (NEW)

Event no. 228563573 located in brick 79117 (NEW)

top view

beam view

mumu

side view

I.P. w.r.t. the vertextrk 145 0.3563 0.1562 0.5 mtrk 206 -0.2815 -0.2423 0.4 mtrk 541 -0.0001 0.0303 62.8 m (mu)

145

541

mu

72853

mu momentum in spectrometer: 17.2 GeV/c decay Pt > 5 GeV

(p22-56 used) daughter angle and momentumtrk145: TX: 0.3519 TY: 0.1485 P = 1.685 -0.447 + 0.951 GeV/c trk206: TX:-0.2698 TY:-0.2425 P = 1.323 -0.351 + 0.747 GeV/c

using these values estimate the mass of the D0 using 3 possibilities for daughters: -Kaon-Pion: 1.26 GeV (+0.52 -0.23) -Pion-Kaon: 1.30 GeV (+0.52 -0.22) -Pion-Pion: 1.09 GeV (+0.58 -0.27) -these values are below the D0 mass (1.864 GeV). -Problably a neutral is missing (also according to the topology).

Muon angle: KALMAN 0.150 0.305

LINEAR 0.144 0.303

14653

ΔZ = 51 m

8 prong vertex or very short decay?

Vertex located in the lead upstream the plate 51

kinematical analysis not possible (downstream brick extracted)

Primary vertex: 59711.0 54774.6 -8818.2Secondary vertex: 59707.3 54769.4 -8767.2

ID X Y Z TX TY IP1 59835.3 55044.4 -8085.4 0.1684 0.3739 4.2 mu momentum 3.7 Gev/c (TT) 2 59607.9 54880.4 -8085.4 -0.1433 0.1437 2.0 3 59514.8 54836.6 -8085.4 -0.2635 0.0789 5.1 4 59898.8 54731.1 -8085.4 0.2570 -0.0548 3.4 5 59535.8 54453.7 -8085.4 -0.2349 -0.4370 3.0 6 59607.2 54412.4 -8085.4 -0.1444 -0.4977 2.9

7 59731.5 54812.4 -8085.4 0.0356 0.0628 0.3 // 10.0 wrt 1ry 8 59624.4 54752.8 -8085.4 -0.1222 -0.0233 0.8 // 5.6 wrt 1ry

All the tracks have been measured in the first plate downstream the primary vertex.

IP distribution

79117

pl 33: 1ry vertex + short charm candidate

secondary interaction

id 8 found in single BT search (low mom, gray)

id 1 mu (not found in CS)

id 7 CS pred

id10 CS pred

id 2

id 3 CS pred

id 5 found in single BT search (low mom)

id3

id2

id1(mu)

id8

id10

Hypothesis (1) 1ry vtx + short vee (daughters: id 3 and id 2)

1ry (103979.1 45758.9 -32325.8) id 1 -0.0318 0.0911 IP wrt 1ry = 0.2 (mu)id10 0.1998 0.2805 IP wrt 1ry = 2.2id 8 0.3420 -0.0740 IP wrt 1ry = 6.5 (gray)id 5 -0.1709 0.0289 IP wrt 1ry = 9.4 (~0.4 GeV)

short vee (103933.6 45782.1 -31727.2) id 2 -0.0685 0.0530 IP wrt vee = 0.3 IP wrt 1ry = 9.4 id 3 0.0050 -0.1310 IP wrt vee = 0.6 IP wrt 1ry =111.8

Beam view

Δz = 599 m

id3

id2

id1(mu) id10

Hypothesis (2) 1ry vertex + short kink (daughter: id 3)

1ry (103979.1 45758.9 -32325.8) id 1 -0.0318 0.0911 IP wrt 1ry = 4.3 (mu)id10 0.1998 0.2805 IP wrt 1ry = 8.0id 2 -0.0685 0.0530 IP wrt 1ry = 3.2id 8 0.3420 -0.0740 IP wrt 1ry = 15.8 (gray)id 5 -0.1709 0.0289 IP wrt 1ry = 12.3 (~0.4 GeV)

short kink daughter id 3 0.0050 -0.1310 IP wrt 1ry =122.7min. kink angle 0.158

Beam view

Result of momentum measurement (preliminary)

id 1 p = 17.0 GeV/c (TT)

id10 p = 4.0 (-2.3 ,+14.4) GeV/c (90%CL) (pl 33-56)id 2 p = 8.8 (-5.5 ,+21.4) GeV/c (90%CL) (pl 33-53)id 3 p = 5.5 (-3.8 ,+10.2) GeV/c (90%CL) (pl 33-56)id 5 p = 0.4 (-0.3 , +1.3) GeV/c (90%CL) (pl 33-39)id 8 gray, not reconstructed

Invariant mass (tracks 2 and 3)K -K : 1.7 (+1.4 -0.4) GeVpi-K : 1.6 (+1.5 -0.4) GeVpi-pi : 1.4 (+1.5 -0.5) GeVK -pi : 1.5 (+1.5 -0.4) GeV

Event 234676119 in 87219: CC or NC?

angle: Kalman -0.110 -0.092

Linear -0.114 -0.063

momentum: 0.87 GeV/c

not found in CS and not found at the primary vertex

should we consider it as a NC?

VTX POS.: 20206.70 32517.10 -12668.10 Tracks angle and IP 0.0285 -0.0179 0.00 -0.3662 0.1468 3.80 -0.0367 0.5623 9.00

127J

ul0

8

Jan

09

Se

p0

8

Ap

r09

10 bricks/week

5.3 bricks/week

Received bricks

Scanning capability for 2009 RUN

15 bricks/week (max) 12 bricks/week (steady) (only location)

10 bricks/week (steady) (including 20% SF and ex.tot.)

“only location” includes charm search: TS of 10 plates downstream

Including:

ScanForth done for all the located events

Extendend TotalScan

20 plates downstream the primary vertex (~50% of the events)

Scanning load is twice wrt “only location”

Conclusions

124 events received

Analysis successfully completed for 110 events

101 neutrino interactions located in the ECC

3 charm candidates

Focus now on charm search: check stopping tracks with large IP wrt to the vertex

Scanning capability 10-15 bricks/week (500-750 in total)

We are ready for the 2x of the 2009 run!