1. ATLAS Collaboration
3000 Physicists including
1000 students

2. ATLAS Computing Development and reliance on the Grid
Novel software that allows users to access computers distributed over the network
Grid effectively turns a global network of computers into one vast computational resource

3. Fundamental Forces 3 3

4. Fundamental Forces
Classically, forces arise as an interaction of a charge or mass with a field
In quantum field theory, forces arise from the exchange of a (gauge) boson
Electromagnetic
electron
photon
Weak Z
Strong
quark
gluon

5. Fundamental Particles
asdf ??

6. Fundamental Particles6

7. Fundamental Particles
Or another pattern to unravel? 7

8. Standard Model Successes
The Standard Model of particle physics is mathematically complete
There are no significant experimental discrepancies with Standard Model predictions
But no Higgs boson has been observed either 8

9. What is the Higgs Boson?

10. What is the Higgs Boson?

11. Standard Model Summary SSB and Massive Higgs Higgs Mechanism Boson
Local
Gauge
Invariance
Massive
Gauge
Bosons 11

12. Standard Model
Standard Model Lagrangian

13. Where to Search for the Higgs
Indirect constraints on the Higgs mass can be found by considering electroweak radiative corrections like 13

14. Higgs Production at the LHC
Gluon Fusion (GGF)
Dominant process
Vector Boson Fusion (VBF)
Second largest cross section
Distinctive topology useful for small mH
Associated W/Z (AW)
Associated Top (AT)
Interesting topologies but smaller cross section 14

15. Higgs Decay Modes
The Standard Model rules say the Higgs decays into the heaviest pair of particles that is kinematically allowed 15

16. Higgs Decay Modes

17. Limit Plots Explained
Limit plots

18. Hot Off the Press Results - ATLAS
We definitely know where the Higgs is NOT hiding (excluded up to 486 GeV)
And we have a hint (only) as to where it may be found
GeV
GeV

19. Hot Off the Press Results - ATLAS
The ATLAS result comes from a combination of searches over many different decay channels 19

20. CMS Result
Also see an excess in that region 20

21. Fermilab (CDF and D0) Results
Also see an excess in that region 21

22. U. of Arizona’s Role Physicists Forward Muon (CSC) Electronics
Integrated Forward
Calorimeters
Massive Forward Radiation
Shield (~700 Metric Tons)

23. ATLAS Forward Calorimeter by UA
Design and construction

24. ATLAS CSC (Electronics) by UA

25. Radiation Shield Design by UA
Simulating and designing shielding to protect detectors and electronics