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Elementary Particle Physics Experiment:
The ATLAS experiment at the LHC
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University of Massachusetts, Amherst
Graduate Research Orientation
1 Feb 2010
Feb 1, 2010
Experimental Particle Physics
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The UMass ATLAS Group
Faculty
– Ben Brau - LGRT 1032
– Carlo Dallapiccola - LGRT 1038
– Stephane Willocq - LGRT 1042
Postdoctoral Researchers
– Ed Moyse, Elisa Pueschel, Niels Van Eldik, Martin
Woudstra - CERN
Graduate Students
– Andrew Meade, Emily Thompson - CERN
– German Colon, Preema Pais, Tulin Verol - LGRT 1036
Feb 1, 2010
Experimental Particle Physics
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What is Particle Physics About?
Experiments can address long standing puzzles / questions:
What are the fundamental constituents of matter?
What are the fundamental forces between elementary
particles?
Can the forces of nature be unified? Including gravity?
What is the origin of mass?
What is the origin of the matter-antimatter asymmetry of the
Universe?
What is dark matter?
Are there extra dimensions?
Feb 1, 2010
Experimental Particle Physics
+ many more…
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How can we answer these
Fundamental Questions?
Particle Accelerators
– Reach very high collision energies to probe
extremely small distance scales (< 10-18 m)
– Research at the energy frontier (a few TeV) with the
ATLAS experiment at the Large Hadron Collider (LHC)
10 x higher energy than previous colliders
search for
Higgs boson (origin of mass?)
SuperSymmetric particles (dark matter candidate?)
New interactions (heavy gauge bosons, extra dimensions?)
Feb 1, 2010
Experimental Particle Physics
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The Large Hadron Collider (LHC)
Proton-proton collider
circumference = 27 km
Energy = 7 TeV / beam
√s = 14 TeV
Lake Geneva
CERN Main Site
ATLAS
CMS
Stored energy / beam
= 350 MJ (!)
Bunch spacing = 25 ns
40 MHz crossing rate
Design luminosity
= 1034 cm-2 s-1
Number of interactions
per crossing ~23
Collisions expected
in late 2009
Run for ~10-15 years
Feb 1, 2010
Experimental Particle Physics
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The ATLAS Detector @ LHC
Muon Detectors
EM Calorimeter
Inner Tracker
Hadronic Calorimeter
Diameter
Barrel toroid length
End-cap end-wall chamber span
Overall weight
Feb 1, 2010
Experimental Particle Physics
25 m
26 m
46 m
7000 Tons
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Feb 1, 2010
Experimental Particle Physics
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▪
November 2005
February 2008
August 2006
Feb 1, 2010
Experimental Particle Physics
September
8 2006
ATLAS Data Event
Feb 1, 2010
Experimental Particle Physics
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UMass Work on ATLAS
Software development for Muon Spectrometer
–
Leading muon reconstruction effort
(SW co-coordinator, EM event data model leader)
–
Validation of detector description, performance improvements
Physics analysis = Search for new physics
–
Search for new heavy gauge bosons (new interactions)
–
Alternatives to Higgs mechanism (origin of mass)
–
Signs of extra (large) dimensions: micro black holes
–
Model-Independent: Hints of things we haven’t thought of yet
More information at http://people.umass.edu/eppex/
Feb 1, 2010
Experimental Particle Physics
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LHC Schedule
First Physics Run at 3.5 GeV on 3.5 GeV begins
now.
Run will continue through 2010 and 2011, with a
goal luminosity of 1 fb-1.
All splices will be repaired in a long (~year)
shutdown.
High-energy 7GeV on 7GeV will begin ~2013.
Feb 1, 2010
Experimental Particle Physics
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