2 nd lhc status report cern 18 dec’09
DESCRIPTION
Candidate Multi Jet Event at 2.36 TeV. T. Virdee On Behalf of the CMS Collaboration. 2 nd LHC Status Report CERN 18 Dec’09 . Summary. CMS has started taking collision data - PowerPoint PPT PresentationTRANSCRIPT
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2nd LHC Status Report
CERN 18 Dec’09
Candidate Multi Jet Event at 2.36 TeV
T. VirdeeOn Behalf of the CMS Collaboration
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Dec09 LHC2- CMS
CMS has started taking collision data
On the average more than 99% of the sub-detector electronic channels are operational. High data-taking efficiency (> 80% for “quiet” or “stable beam” flag (all CMS ON))
All indications are that:
data can be analysed rapidly – all chains are working well, the performance is according to design (almost all distributions
agree well with the simulations at the fine level), CMS is starting to produce results from collision data.
Summary
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CMS Detector
Dec09 LHC2- CMS
4T Superconducting Solenoid All Silicon Tracker (pixels and microstrips)Lead tungstate electromagnetic calorimeterHermetic CalorimetryRedundancy in the Muon system
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Dec09 LHC2- CMS
Since Sept. ‘08 – extensive tests Cosmics data taking in Oct’08 and Aug’09 (CRAFT), Offline and Computing tests, Prompt physics analysis exercise in Oct’09.
Prologue
Cosmic Muon
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CRAFT: 23 Papers Submitted to JINST
Dec09 LHC2- CMS
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Start of the LHC: First CollisionsMonday 23rd November
Dec09 LHC2- CMS
CMS Experiment at the LHC, CERNDate Recorded: 2009-11-23 19:21 CETRun/Event: 122314/1514552 Candidate Collision Event
Events recorded: All CMS ON900GeV: ~400k2.36 TeV: ~20k
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First Di-photon Distribution in CMS
Dec09 LHC2- CMS
First shown on Thur 27th Nov, Today’s distributions shown below
• Data and MC comparison (uncorrected distributions)
• Almost identical S/B, mass and width compatible
• M(p0) is low in both data and MC - Mostly due to the readout threshold (100 MeV/Crystal) and conversions
Using “out of the box” corrections
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Rapid Analysis
Dec09 LHC2- CMS
Sunday 6th Early Morning: First “Physics” Fill4x4 bunches, S ~ e10 protons, Stable Beam Flag set for the first time
All of CMS was Switched ON
Monday 7th : First K0S & L
L
M=497.7 MeV/c2, s=7.6 MeV/c2
K0s
M=1.116 GeV/c2, s=3.1 MeV/c2
Sunday 6th : 9amLHC Run Meeting
CMS 2009 Preliminary
Charged particle pT spectrum
Data
MC
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Detector Performance : Tracking
Dec09 LHC2- CMS
Primary Vertex Strip TrackerPixels Clusters
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Data: N(h)/N(p0) = 0.020 ± 0.003 MC: N(h)/N(p0) = 0.021 ± 0.003
Eta and Phi
Dec09 LHC2- CMS
hCMS 2009 Preliminary
Uncorrected
f CMS 2009 Preliminary
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Calorimeters
Dec09 LHC2- CMS
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Detector Performance : Calorimetry
Dec09 LHC2- CMS
Jets and Missing ET
Calo JetsDi-Jets
Calo Jets
Jets+TracksDi-Jets
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Detector Performance : Particle Flow
Dec09 LHC2- CMS
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Reconstruction of Electrons
Dec09 LHC2- CMS
2.5 GeV electron with bremstrahlung
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Muons: A Dimuon Event at 2.36 TeV
pT(m1) = 3.6 GeV, pT(m2) = 2.6 GeV, m(mm)= 3.03 GeVDec09 LHC2- CMS
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First Physics Distributions
Dec09 LHC2- CMS
CMS 2009 Preliminary
Charged Particle Multiplicity Average pT
correlated systematic error
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Dec09 LHC2- CMS
CMS has started taking collisions dataOn the average more than 99% of the sub-detector electronic channels are operational. High data-taking efficiency (> 80% for “quiet” or “stable beam” flag (all CMS ON))All indications are that: data can be analysed rapidly – all chains are working well, the performance is according to design (almost all distributions agree well with
the simulations at the fine level), CMS is starting to produce results from collision data.
Summary Again!
We have finished the year on a high note BUTit is only the beginning of the physics exploitation phase of the LHC.
Very encouraging collision data-taking start which augurs well for the future.
Thanks to the LHC !!