Naslov
Study of vector boson scattering in events with four leptons and two jets with CMS detector at the LHC

Autori
Duje Giljanović

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, doktorska disertacija

Fakultet
Prirodoslovno matematički fakultet

Mjesto
Zagreb

Datum
09.12

Godina
2022

Stranica
267

Mentor
Damir Lelas ; Claude Charlot

Ključne riječi
CMS, LHC, VBS, ZZ

Sažetak
Studying Vector Boson Scattering is crucial for understanding the electroweak symmetry breaking mechanism and it provides a complementary tool for measuring Higgs boson couplings to vector bosons. In this study I analyse 137 fb^{;-1}; of proton- proton collisions produced at CERN Large Hadron Collider (LHC) at 13 TeV centre-of-mass energy. Additionally, I presented a prospective study on the longitudinal scattering in the same channel at High-Luminosity (HL-LHC) and High-Energy LHC (HE- LHC) conditions, corresponding to 14 and 27 TeV centre-of-mass energy, respectively, with full event kinematics simulated. Finally, I present my work on improving the measurement of electron selection efficiency for the 2016, 2017 and 2018 data-taking periods. The EW production of two jets in association with two Z bosons was measured with an observed (expected) significance of 4.0 (3.5) standard deviations. The cross sections for the EW production were measured in three fiducial volumes and is $0.33_{;(-0.10)};^{;(+0.11)}; (stat)_{;(-0.03)};^{;(+0.04)};(syst)\ fb$ in the most inclusive volume, in agreement with the Standard Model (SM) prediction of $0.275 \pm 0.021\ fb$. Limits on the anomalous quartic gauge couplings were derived in terms of EFT operators T0, T1, T2, T8, and T9. \\ A measurement of the longitudinal scattering in the ZZ channel is expected at 27 TeV, corresponding to an integrated luminosity of $15 000 fb^{;-1};$, with a signal significance of 4.6 standard deviations. By extending the electron acceptance from $|\eta|= 3$ to $|\eta|= 4$, the first observation is expected with a significance of 5.4 standard deviations. Hence, this study demonstrates a significant benefit of further energy increase at the LHC for understanding the EW sector of the SM.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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