Tag: Boson

Free Download Search for Invisible Decays of the Higgs Boson Produced via Vector Boson Fusion at the LHC with CMS Run 2 data
English | 2024 | ISBN: 3031783646 | 145 Pages | PDF EPUB (True) | 49 MB
This thesis reports the latest measurements on one of the leading dark matter searches conducted by the Compact Muon Solenoid (CMS) experiment at CERN, leading to some of the most stringent constraints on hypothesized interactions between the Higgs boson and dark matter. The thesis also includes further research about the future outlook of the experiment, including exploratory research on the adaptation of deep learning models in future dark matter analyses to improve analysis sensitivity, and the design of a new type of data processing hardware to be used in the next phase of the CMS experiment.

Free Download Interacting Boson Model from Energy Density Functionals By Kosuke Nomura (auth.)
2013 | 188 Pages | ISBN: 4431542337 | PDF | 7 MB
This thesis describes a novel and robust way of deriving a Hamiltonian of the interacting boson model based on microscopic nuclear energy density functional theory. Based on the fact that the multi-nucleon induced surface deformation of finite nucleus can be simulated by effective boson degrees of freedom, observables in the intrinsic frame, obtained from self-consistent mean-field method with a microscopic energy density functional, are mapped onto the boson analog. Thereby, the excitation spectra and the transition rates for the relevant collective states having good symmetry quantum numbers are calculated by the subsequent diagonalization of the mapped boson Hamiltonian. Because the density functional approach gives an accurate global description of nuclear bulk properties, the interacting boson model is derived for various situations of nuclear shape phenomena, including those of the exotic nuclei investigated at rare-isotope beam facilities around the world. This work provides, for the first time, crucial pieces of information about how the interacting boson model is justified and derived from nucleon degrees of freedom in a comprehensive manner.

Free Download High-Precision W-Boson Studies with LHCb: Measurements of the W Boson’s Mass and Lepton Flavour Universality, and Trigger Development for the LHCb Upgrade by Ross Hunter
English | PDF EPUB (True) | 2024 | 179 Pages | ISBN : 3031497023 | 29.4 MB
This book details a new and ground-breaking contribution to the search for a successor to the Standard Model (SM) of particle physics – the largest modern endeavour in the field. In the hope of seeing a discrepancy with the SM’s predictions, this work discusses two hitherto unforeseen measurements at the frontier of experimental precision: a measurement of W-boson mass and a test of the fundamental axiom of the W boson’s lepton flavour universality (LFU). Both measurements are made by analysing collision data from the LHCb experiment at the Large Hadron Collider (LHC) at CERN, and represent the establishment of a new field of high-precision Standard Model tests with LHCb. This book also describes the development of new software tools for the optimisation of the LHCb trigger system, which helps to ensure that LHCb’s exciting physics program can continue to prosper into the future. This book is accessible to those with graduate-or master’s-level training in experimental particle physics.

Free Download The Beauty and the Boost: A Higgs Boson Tale:
Measurements of Higgs Boson Production at High Energy in Decays to Bottom Quarks
English | 2023 | ISBN: 3031394410 | 407 Pages | EPUB (True) | 58 MB

Free Download The Beauty and the Boost: A Higgs Boson Tale: Measurements of Higgs Boson Production at High Energy in Decays to Bottom Quarks and Their Interpretations with the ATLAS Experiment at the LHC by Brian Moser
English | PDF (True) | 2023 | 250 Pages | ISBN : 3031394410 | 7.1 MB
Precision measurements of the Higgs boson’s properties are a powerful tool to look for deviations from the predictions of the Standard Model (SM) of particle physics. The 139/fb of proton-proton collision data which have been collected by the ATLAS experiment during Run 2 of the LHC, offer an opportunity to investigate rare Higgs-boson topologies, which are particularly sensitive to new physics scenarios but experimentally difficult to access. Several such measurements, which target Higgs-boson decays to heavy-flavour quarks, as well as their combinations are presented in this thesis. A novel analysis that measures Higgs-boson production in association with a heavy vector boson V (VH, with V=W,Z) at high energies is presented. Dedicated Higgs-boson reconstruction techniques are applied to reconstruct the highly Lorentz-boosted Higgs-boson decays into pairs of bottom quarks. The measurement is subsequently combined with a VH cross-section measurement at low and intermediate pT(V) to provide a differential cross-section measurement in kinematic fiducial volumes over the largest possible pT(V) range. All cross-section measurements agree with the SM predictions within relative uncertainties that range from 30% to 300%. The results are furthermore interpreted as limits on the parameters of a SM effective field theory. Finally, a combination of measurements of Higgs decays to heavy-flavour quarks is used to experimentally determine that the Higgs-boson coupling to charm quarks is weaker than to bottom quarks, as predicted by the SM. The target audience for the thesis are physicists and physics students, in particular those with a background in high energy physics.