first thoughts on pixel alignment

1
first thoughts on pixel alignment

• Ulrich Heintz
• Boston University

2
how many muons will there be?

• thanks to Stephane Willoq for pointers

3
sources of muons
from Bottom Production, P. Nason et al,
hep-ph/0003142
4
sources of muons
5
LVL-2 10 ms Input 100 kHz Output 1000 Hz
EF 1 s Input
LVL-1 2.5 ms fixed Input 40 MHz Output 75 kHz
mFast
mComb
mIsol
barrel
B-Physics Processor
TrigMoore
ROI
JrigJPsi
mCTPI
CTP
endcap
mTile
from A. Nisati, ATLAS Muon Workshop Cetraro,
11-15 July, 2005
6
level-1 barrel trigger rates
Low-pT Trigger rates 11 kHz High-pT Trigger
rates 2.5 kHz
Layout Q02 Layout P03
from Francesco Conventi, Atlas Muon Workshop
Cetraro, 14 Luglio 2005
7
level-2 muon trigger rates
from Alessandro Di Mattia 10th ATLAS Muon
week Cetraro, July 10 15 2005
Barrel, Muon Layout O
8
TrigJPsi selection of J/? channel
J/? at Level-2 trigger why?

• The LVL1 trigger retains 23 kHz of events with
  one ?gt6 GeV candidate.
• Only 4 kHz of these are b events, others are
  muons from K/? decays or cavern background.
• LVL2 trigger will select 1/50 events
• Instead of retaining a random fraction of ? gt 6
  GeV, or only higher pT muons, we would like to be
  efficient for gold channels (i.e. J/?)
• This algorithm can run after that one ? gt 6
  GeV was confirmed at LVL2

9
event filter muon trigger rates
EF efficiency curves are convolved to the known
cross sections for two scenarios the 6 GeV
threshold at 1033 cm-2s-1 luminosity and the 20
GeV at 1034 cm-2s-1. First results for the full
trigger chain (barrel, Layout Q, efficiency
w.r.t. LVL2 used)
from Andrea Ventura, ATLAS Muon Week Cetraro,
July 10-15 2005
Higher Layout Q statistics is running to better
parametrize efficiency curves
10
how many muons do we need?

• thanks to
• Tobias Golling, Marian Zdrazil, Kevin Black for
  help with code
• starting point InDetAlignAlgs, SiRobustAlign
  packages

11
pixel detector geometry
12
pixel geometry
13
philosophy

• with small data samples
• minimize number of free parameters
• use survey to fix detectors within disks and
  barrels
• align barrels and disks as rigid objects
• up to 54 parameters
• 3 barrels, 6 disks
• 3 positions, 3 angles
• caveat assumes SCT is already aligned

14
define ?2
15
residuals
perfect alignment
xy shift of layer 1
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minimize ?2
17
?2 for x-shift of one barrel

• agrees well with parabola

18
shifts in x,y,z of gt1 barrel
dx1 dx2 dy1 (mm)
?2
19
plans

• determine number of tracks needed for alignment
• are there enough muons from resonances?
• in 1 pb-1 probably a few k
• investigate muon reconstruction
• use Rome muon MC samples to perform alignment

20
monkeywrenches

• CMTgt Warning package LCGEnv v not found
  (requested by xternalComponents)
• CMTgt Warning package GaudiPolicy v not found
  (requested by ExternalPolicy)
• CMTgt Warning package GaudiPolicy v not found
  (requested by AtlasCxxPolicy)
• CMTgt Warning package GaudiPolicy v not found
  (requested by AtlasFortranPolicy)
• CMTgt Warning package GaudiKernel v not found
  (requested by GaudiInterface)
• CMTgt Warning package GaudiHistory v not found
  (requested by StoreGate)
• CMTgt Warning package PartPropSvc v not found
  (requested by InDetAlignAlgs)
• CMTgt Warning package PartPropSvc v not found
  (requested by iPatTruthTrajectory)

21
sources of muons
from BOTTOM PRODUCTION P. Nason et al,
hep-ph/0003142
22
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