Downstream background?

Taku YamanakaDec. 2, 2013OSK Meeting

Data

Got simple ROOT file with gamma information from Shiomi-kun.

2

Original Z vs Pt3

RecZ1000 2000 3000 4000 5000 6000

Pt

0

200

400

600

800

1000

1200

1400

1600

1800

Pt:RecZ {zaxis>2000}

4

m2�� = E1E2(1� cos �)

cos � = 1�m2

��

E1E2

Opening Angle5

a559312994ae427a8892d96685601292

Entries 19607Mean 0.5309RMS 0.1364

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

100

200

300

400

500

600

a559312994ae427a8892d96685601292

Entries 19607Mean 0.5309RMS 0.1364

Two photon separation~20cm

6

GammaPos[0][1]-GammaPos[1][1]-1500 -1000 -500 0 500 1000 1500

Gam

maP

os[0

][0]-G

amm

aPos

[1][0

]

-1500

-1000

-500

0

500

1000

GammaPos[0][0]-GammaPos[1][0]:GammaPos[0][1]-GammaPos[1][1] {GammaPos[0][0]<150}

Z Reconstruction

Simple

3D

7

RecZ vs ZsimpleWrong slope

8

RecZ2000 2500 3000 3500 4000 4500 5000 5500 6000

zsim

p

3000

3500

4000

4500

5000

5500

6000

zsimp:RecZ {RecZ>2000}

RecZ vs Z3DWrong slope

9

RecZ2000 2500 3000 3500 4000 4500 5000 5500 6000

zaxi

s

3000

3500

4000

4500

5000

5500

6000

zaxis:RecZ {RecZ>2000}

Mγγ w/RecZ is 95MeV/c2

10

faa354e695984311be662653f61db30a

Entries 19607Mean 95.44RMS 3.728e-05

0 20 40 60 80 100 120 1400

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000faa354e695984311be662653f61db30a

Entries 19607Mean 95.44RMS 3.728e-05

Z3D vs PT(using Z3D)11

zaxis2000 2500 3000 3500 4000 4500 5000 5500 6000

pt3d

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

pt3d:zaxis {zaxis>2000}

Hit positionsWhat is this ring?

12

-1000 -800 -600 -400 -200 0 200 400 600 800 1000-1000

-800

-600

-400

-200

0

200

400

600

800

1000 ee66f15501344c39a8a76801f8be8b28

Entries 19607Mean x -23.96Mean y -0.145RMS x 234.9RMS y 236.2

ee66f15501344c39a8a76801f8be8b28

Entries 19607Mean x -23.96Mean y -0.145RMS x 234.9RMS y 236.2

Conclusion

Bug in reconstruction code??

13