1. Žilina,
Z path with ATLAS data
Ivan Melo

2. Particles of the Standard Model
Z - path
Z - path

3. Urýchľovače – továrne na nové častice
E = mc2
p + p → Z
p + p → H
91 GeV
91 GeV
91 GeV
125 GeV
1 GeV + 1 GeV + Ekin = GeV 3

4. Transverse momentum pT
Sum of initial pT = 0
Sum of final pT = 0

5. Z and Higgs production (Feynman diagrams)

6. Z - path

7. Z - path

8. Invariantná hmotnosť

9. Invariantná hmotnosť
Signál +pozadie
Pozadie (background)

11. ATLAS detector Elmag. kalorimeter Hadrónový kalorimeter
Miónové detektory
Dráhový detektor

12. pp -> Z -> e+e-

13. e+e-

14. e+e-

17. γγ

18. γγ

21. Veľa dráh, 2 eventy naraz (pile-up)

22. kvarky (a gluóny) vidíme ako „jety“, spŕšky hadrónov

23. neutríno
Missing ET = missing pT > 25 GeV

24. Pick assigned number (1 or 2) and letter (A,B,C,....,Z)
ATLAS Z-path
Hypatia
1.Download Unzip it onto your Desktop To start HYPATIA:
a. Navigate to the HYPATIA folder you downloaded
b. On Windows and Mac:oDouble click on“Hypatia_7.4_Masterclass.jar”
c. On Linux: Right click on “HYPATIA_for_Linux.sh” and change permissions so that it is executable. Double-click on “HYPATIA_for_Linux.sh”
To access ATLAS data:
username: ippog
password: mc13
Pick assigned number (1 or 2) and letter (A,B,C,....,Z)

25. Datasets: ATLAS real pp-data from 2012 at 8 TeV
Di-leptons: ~ events
- Di-electrons and di-muons from Z (mainly), Jpsi and Upsilon
fully simulated Z’ events (mass 1 TeV)
Higgs candidates: real data events corresponding to 2 fb-1
- Di-photon: events cuts as in ATLAS publication–including converted photons
- 4-leptons: 40 events cuts as in ATLAS publication
- very little background!
- almost no need to discuss ET miss!

26. Analysis - Evaluate your set of 50 events (e.g. 1C)
- Make notes on your tally sheet (e.g. 1C)
- Consult cheat list for students:
Set pT cut at 5 – 10 GeV
Check tracks and physics objects
If two tracks (+- charge) point to two elmag clusters in both views – e+e- candidate
If no tracks point to two elmag clusters in both views - γγ candidate
If two tracks (+- charge) continue to muon chambers – μμ candidate
If four charged tracks (+-+-) - μμμμ, μμee, eeee candidate
Check Pixel hits >= 2 and SCT hits >= 7 to see if particles come from the same vertex
In case of converted photon candidate: check invariant mass of the (+-) double track, if
close to 0, it is photon converted to e+e-
- Enter candidate tracks as ee, μμ, γγ to see their invariant mass
- Export invariant mass table as .txt file (File – Export invariant masses)

27. How to submit results
OploT:
Click on Student For test pick January , any test city, group number and letter Upload your .txt file with invariant masses (Browse button)
If you need to delete a students upload, you can do this from the Administrator tab. Password:
username: admin
password: administrator

28. Chýbajúca priečna hybnosť
If sum of final pT ≠ 0:
1+2+3 1 2 3
Missing pT = Missing ET = ETMiss
ETMiss > 25 GeV (asi neutríno)
ETMiss < 25 GeV (nie neutríno, skôr nedokonalosť detektora)