Search for Higgs decay to dark matter and trigger studies
File(s)
PhD Thesis
Author(s)
Arnauth Pela, Joao Pela
Type
Thesis
Abstract
The Compact Muon Solenoid (CMS) is a general-purpose particle detector at the CERN Large Hadron Collider (LHC). The goal of this experiment is to search for the Higgs boson and evidence of new physics and to test the prediction of the Standard Model (SM) at the TeV scale. This thesis describes the analysis of proton-proton collision data recorded by CMS during 2012 and support work for data taking during the same period.
A search for the Vector Boson Fusion (VBF) produced Higgs boson invisible decays, using 19.5 fb^-1 of data recorded with prompt reconstruction triggers at a center of mass energy of 8 TeV, is presented. Events are selected with two forward jets and large Missing Transverse Momentum. Assuming the SM VBF production cross section and acceptance, the observed (expected) upper limit at the 95% confidence level on the BR(H->inv), is determined to be of 65% (49%) for mH=125 GeV.
A second search for the VBF Higgs boson invisible decays, using 19.2 fb^-1 of data recorded with delayed reconstruction (parked) triggers at a center of mass energy of 8 TeV, is also presented. A new event selection was developed taking advantage of the lower trigger requirements. Assuming the SM VBF Higgs production cross section and acceptance, the observed (expected) upper limit at the 95% confidence level on the BR(H->inv), is determined to be 57% (40%) for mH=125 GeV.
Monitoring for the CMS Level 1 Trigger system has been developed and used during the 2012 and subsequent LHC data acquisition periods. Contributing to the high reliability of this system during data taking and providing crucial information for validation of the data quality.
A search for the Vector Boson Fusion (VBF) produced Higgs boson invisible decays, using 19.5 fb^-1 of data recorded with prompt reconstruction triggers at a center of mass energy of 8 TeV, is presented. Events are selected with two forward jets and large Missing Transverse Momentum. Assuming the SM VBF production cross section and acceptance, the observed (expected) upper limit at the 95% confidence level on the BR(H->inv), is determined to be of 65% (49%) for mH=125 GeV.
A second search for the VBF Higgs boson invisible decays, using 19.2 fb^-1 of data recorded with delayed reconstruction (parked) triggers at a center of mass energy of 8 TeV, is also presented. A new event selection was developed taking advantage of the lower trigger requirements. Assuming the SM VBF Higgs production cross section and acceptance, the observed (expected) upper limit at the 95% confidence level on the BR(H->inv), is determined to be 57% (40%) for mH=125 GeV.
Monitoring for the CMS Level 1 Trigger system has been developed and used during the 2012 and subsequent LHC data acquisition periods. Contributing to the high reliability of this system during data taking and providing crucial information for validation of the data quality.
Version
Open Access
Date Issued
2015-12
Date Awarded
2016-09
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Colling, David
Sponsor
Fundacao para a Ciencia e a Tecnologia
Grant Number
SFRH/BD/77979/2011
Publisher Department
Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)