Measurement of the Cross section for associated production of the Higgs boson and an electroweak boson in final states with two b quarks and two leptons in proton proton collisions at the Large Hadron Collider

Mishra, Saswat (2023) Measurement of the Cross section for associated production of the Higgs boson and an electroweak boson in final states with two b quarks and two leptons in proton proton collisions at the Large Hadron Collider. Doctoral thesis, University of Zagreb.

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Abstract

This thesis summarizes the analysis in which we measure the cross-section for the production of the standard model Higss boson of 125 GeV in association with an electroweak boson (W or Z). The analysis is performed in the final state where the Higgs boson decays into a pair of b quarks and the electroweak boson decays leptonically resulting in three channels based on the number of charged leptons in the final state (0, 1 or 2 leptons). The analysis uses data recorded by the CMS experiment from proton-proton collisions at √s= 13 TeV in the LHC during the full Run 2 data taking period (2016-2018). The recorded data corresponds to an integrated luminosity of 138 fb−1. The analysis searches for 2 b-jets produced from b-quarks originating from the Higgs boson along with lepton candidates decaying from the vector boson. The mass of the Higgs boson is reconstructed from the four momenta of the b-jets which are identified using b-tagging algorithms. To account for events with a Lorentz boosted Higgs boson, a single large cone jet is reconstructed which consists of the two b-jets merged together due to the boost. Taking this into account, separate analysis called the boosted analysis is performed along with the nominal resolved analysis to improve sensitivity in high pT phase space. Both resolved and boosted analysis are combined together in the final fit to enhance precision of the measurement. To reduce the dependency on theoretical uncertainties this measurement is performed in the simplified template cross-section (STXS) scheme. This also allows for straightforward comparison of theoretical models using such measurements. Under this scheme, the cross section measurement is done in regions delineated by type of vector boson (W or Z), vector boson transverse momentum (pT ), and the presence of additional jets.

Item Type:	Thesis (Doctoral thesis)
Uncontrolled Keywords:	LHC; CMS; standard model; Higgs boson; boosted objects; DeepCSV; DeepAK8; STXS
Subjects:	NATURAL SCIENCES > Physics > Physics of Elementary Particles and Fields
Divisions:	Division of Experimental Physics
Projects:	Project title Project leader Project code Project type Sto dvadeset i pet milijuna piksela za otkriće vezanja Higgsovog bozona na fermione i novih čestica na Velikom hadronskom sudarivaču-HIGGS125 Vuko Brigljević; Saša Mićanović; Benjamin Mesić IP-2016-06-3321 HRZZ
Depositing User:	Saswat Mishra
Date Deposited:	06 Jul 2023 10:34
URI:	http://fulir.irb.hr/id/eprint/8039

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