1. Particle physics
at the LHC and ATLAS

2. Experimental particle physics depends on two physics principles
Basic assumptions
Experimental particle physics depends on two physics principles
Conservation of Momentum
Conservation of Mass-Energy (E=mc2)
and
The Standard Model.

3. The Standard Model

4. The LHC and New Physics
It’s a time of exciting new discoveries in particle physics!
At CERN, the LHC successfully completed
RunI, colliding protons at 8 TeV of collision energy to confirm that the measurements correspond well to the Standard Model and then find the Higgs boson. The LHC is now into Run II at an amazing 13 TeV and the task is to look for new phenomena…and we are off to a great start.

5. The LHC and New Physics
The LHC is buried ~100 m below the surface near the Swiss-French border.

6. How protons are accelerated

7. Protons Collide If each beam proton has energy 6.5 TeV....
The total collision energy is 2 x 6.5 TeV = 13 TeV.
But each particle inside a proton shares only a portion.
The collision energy makes new particles, some more massive than the proton. Remember: E=mc2! 7

8. Particle Decays
The Higgs boson was discovered by CMS and ATLAS and announced on July 4, This long-sought particle is part of the “Higgs mechanism” that accounts for other particle having mass.
We never directly “saw” the Higgs. We detected daughter particles that came from the Higgs as it promptly decayed.

9. Detecting what comes out
Generic Design
Cylinders wrapped around the beam pipe
From inner to outer . . .
Tracking
Electromagnetic calorimeter
Hadronic calorimeter
Magnet*
Muon chamber
*Location of magnet depends on specific detector design. 9

10. The ATLAS detector

11. The ATLAS Detector Play with ATLAS online at http://tiny.cc/0y1jiy.
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Play with ATLAS online at

12. An ATLAS event
What new laws can we discover for elementary particles?