Display ttbar events

1
Display ttbar events

• Global view
• Primary vertex
• B-tagging
• Electron (ID, calo)
• Muon (ID, spectro, combined)

2
Global view

• Ex tt?Wb Wb ?eneb mnmb (Evt 5 in first file of
  5200 with 11.0.41)

f
Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
ne 22 19 0.61 -4
nm 127 87 0.92 -22
pTmiss
b2
b1
el
el
Other jet
pTmiss
b1
b2

• Big activity in endcaps (hgt1.4) !
• Circles, squares size to E
• Evt rejected because of muon pTlt20 GeV
• Pb 1 Some circles have no E ?
• Pb 2 Muon ID track bad r-z view

b2
m
m
el
b1
3
Primary vertex
Reconstructed tracks Monte Carlo tracks
Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
n1 22 19 0.61 -4
n2 127 87 0.92 -22
X-Y plane pT gt 1 GeV
y
p
Detector center
X
Rec. vertex
e
m
Monte Carlo vertex
e
p
p
25 mm
m
S
r-Z plane pT gt 5 GeV
?

• Transverse plane Primary vertex displaced by
  30mm, precision 15 mm
• z Primary vertex displaced by 1cm, precision
  100 mm
• Pb 4 particles (3p, 1S) originated from the MC
  vertex. FSR from jets?

z
Detector center
Rec. vertex
Monte Carlo vertex
m
m
e
e
2 mm
4
B tagging
Reconstructed tracks Monte Carlo tracks
Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
n1 22 19 0.61 -4
n2 127 87 0.92 -22
X-Y pT gt 5 GeV
b2
X-Y (j1) pT gt 5 GeV
Detector center
Monte Carlo vertex
e
1 mm
Detector center
m
10 mm
3 mm
b1
2 mm
j1

X-Y (j2) pT gt 5 GeV
b2
SV1IP3D
b-jet 1 8.4
b-jet 2 5.0

• Reconstructed vertex j1 clearly visible because
  of large IP
• Less impressive for j2, but more tracks

4 mm
Monte Carlo vertex
Detector center
5
Electron in ID
Reconstructed electron Reconstructed
tracks Monte Carlo tracks
pT rec (GeV) h rec f rec (deg)
Elec. 53.2 -0.88 -179
j2
Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
n1 22 19 0.61 -4
n2 127 87 0.92 -22
InDet
Pixel (12)
BarrelEndcaps
el
j1
SCT (4x2)
TRT (0)
6
Electron, jets in calorimeters

• tt?Wb Wb ?eneb mnmb (Evt 5 in first file of
  5200 with 11.0.41)

Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
n1 22 19 0.61 -4
n2 127 87 0.92 -22
E rec (GeV) h rec f rec (deg)
Elec. 72.5 -0.88 -179
b-jet 1 90 -0.21 -61
b-jet 2 203 -0.76 105
ESD Jet DR0.4
Electron
b2
b1

• Big activity in endcaps, but low E !
• For jets, most of the E in the EM
• E(el) by summing cells 62 GeV (no cluster
  correction)
• Cone size 0.4 OK for jets (white circle)
• Pb Which center for ESD jet radius ?

Other jet (39 GeV)
f
180
270
90
0
7
Muon in ID
Reconstructed Muon Reconstructed tracks Monte
Carlo tracks
pT rec (GeV) h rec f rec (deg)
Muon 17.3 1.70 -173
b2
Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
n1 22 19 0.61 -4
n2 127 87 0.92 -22
InDet
Pixel (3)
BarrelEndcaps
m
b1
SCT (5)
TRT
Zlt0??
8
Muon in spectro
Spectro /IP p rec (GeV) h rec f rec (deg)
Muon 46/49 1.70/1.69 -174/-174
y
Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
n1 22 19 0.61 -4
n2 127 87 0.92 -22
z
MDT 1
MDT 2
MDT 3
TGC 1
TGC 2
TGC 3,4
Chambers fired by jet punchthrough ? No track
reconstructed
x
z

• Muonboy builds segments in each chambers
• Extrapolation from the outside
• Global track fit performed on spectro hits
• Extract p (not pT) because bending in R-z
• Track propagation to IP with an average E loss of
  3 GeV

Zoom MDT1
O hit(tdrift)
-- segment
y
m
z
9
Combined muon
pT rec (GeV) h rec f rec (deg)
Muon 17.3 1.70 -173
Truth E (GeV) pT (GeV) h f (deg)
Elec. 75 53 -0.87 -179
b1 85 83 -0.2 -60
b2 182 140 -0.75 105
Muon 48 17 1.69 -172
n1 22 19 0.61 -4
n2 127 87 0.92 -22
Muon

• Reconstruction mainly used ID at 50 GeV !
• On x-y view only barrel muon chambers are shown
  (hlt0.8). Muon track not shown

Chambers fired by jet punchthrough ? No track
reconstructed
Muon