Measurement of the W boson mass and the calibration of the muon momentum with the ATLAS detector

Abstract

U ovoj tezi je opisano meree mase W bozona, koje se zasniva na podacima prikup enim na detektoru ATLAS tokom 2011. godine u proton{proton sudarima na energiji od 7 TeV na Velikom sudaraqu hadrona (LHC). Prema Standardnom modelu masa W bozona zavisi od mase top kvarka i mase Higsovog bozona kroz korekcije vixeg reda. Preciznim mereem mase top kvarka, W i Higsovog bozona mogue je testirae konzistentnosti Standardnog modela, i bilo koje neslagae predstav a indirektan dokaz postojaa qestica izvan Standardnog modela. Masa W bozona je preth- odno izmerena na eksperimentima na Velikom eletron{pozitronskom su- daraqu, kao i na eksperimentima CDF i D0 na proton{antiproton su- daraqu Tevatron. Trenutna sreda vrednost izmerene mase W bozona iznosi mW = 80385 15 MeV, dok je najpreciznije meree ostvareno na eksperimentu CDF sa neodreenoxu 19 MeV. Sa druge strane, na osno- vu globalnog fita parametara Standardnog modela predviena masa W bozona iznosi mW = 80358 8 MeV...

In this thesis measurement of the W-boson mass based on data collected during 2011 in proton–proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS detector at the Large Hadron Collider (LHC) is presented. In the Standard Model, the Wboson mass depends on the top quark mass and the Higgs-boson mass through higher order corrections. Therefore, a precise measurements the mass of the top quark, Wand Higgs-boson, provide a stringent test of the Standard Model. Any observed inconsistency can be an indirect proof of the physics beyond the Standard Model. Previous measurements of the mass of the W boson are performed at the Large electron–positron collider, and at the Tevatron proton–antiproton collider with the CDF and D0 experiments. The current world average value of the W-boson mass is mW = 8038515 MeV, while the most precise single measurement with an uncertainty of 19 MeV is performed with the CDF experiment. On the other hand, the indirect constraint on the W-boson mass from the global electroweak fit predicts mW = 80358 8 MeV...