W path with ATLAS data Žilina, Ivan Melo

Particles of the Standard Model W - path Hadrons: p, n, π, K,...

27 km supravodivých magnetov chladených na 1,9 Kelvina

Urýchľovače – továrne na nové častice E = mc 2 p + p → H GeV + 1 GeV + E kin = 125 GeV 91 GeV 125 GeV +...

ATLAS detector Elmag. kalorimeter Hadrónový kalorimeter Dráhový detektor Miónové detektory

pp -> Z -> e+e-

pT1pT1 pT2pT2 Sum of initial p T = 0Sum of final p T = 0 Transverse momentum p T

If sum of final p T ≠ 0: Missing p T = Missing E T = ETMiss Chýbajúca priečna hybnosť ETMiss > 20 GeV (asi neutríno) ETMiss < 20 GeV (nie neutríno, skôr nedokonalosť detektora)

Beta decay

W production and decay

Higgs boson production

W - path

HW+ W- e+μ- νν e+e- νν μ+μ- νν μ+e- νν Higgs boson decay via WW channel W decay

pp -> Z -> e+e-

e - /e +

μ-/μ+μ-/μ+

μ-/μ+μ-/μ+

neutríno Missing ET = missing pT > 20 GeV

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

Veľa dráh, 2 eventy naraz (pile-up)

Invariantná hmotnosť

Pozadie (background) Signál +pozadie

To access ATLAS data: username: ippog password: mc13 Pick assigned number (1 or 2) and letter (A,B,C,....,Z) s ATLAS Z-path Hypatia 1.Download 2.Unzip it onto your Desktop 3.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”

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!

- 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) Analysis

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 How to submit results