1. Higgs Identification In ATLAS Experiment
XU Jun YE Peiran
Supervisor: Ana DUMITRIU
CPPM
21/07/2017

2. Procedure Theoretical part - Higgs boson
- Decay channel and the percentage
- Reason that we choose this decay(H->ZZ/γγ)
Experiment
- recognize the decay products
- reproduce the mass

3. Higgs Boson
Discovery
Basic character: mass, etc.
Feyman Diagram

4. Decay Channel -Main Decay Channel: H->bb (57%) H->W+W- (21%)
H->gg (9%)
-Problem:
bb:background
WW:hard to control the missing energy

5. Decay Channel in this project
The main decay in this experiment:
H->γγ
H->4l
Reason:
Easy to reconstruct and measure in detectors
Give a clean signal although the statistics is limited

6. Experiment
Reference:

7. 120.117GeV eeμμ 91.329GeV ee 4 leptons charge 2 photons
The trick you will use to be pretty sure that an actual particle was created in the collision is not only to recognize the decay products, such as muon-antimuon, electron-positron or photon-photon pairs, but also to reconstruct the mass of the decaying particle.
GeV
eeμμ
91.329GeV ee

8. GeV
eeee
95.647GeV μμ

9. Result ee μμ γγ eeee eeμμ 9 7 22 2
Standard deviation of sample ~140

10. Mean is far from the value of higgs , which is 125GeV

11. Thanks for your attention
CPPM
21/07/2017