Search for Higgs Boson Decays to Charm Quarks with the ATLAS Experiment and Development of Novel Silicon Pixel Detectors

Search for Higgs Boson Decays to Charm Quarks with the ATLAS Experiment and Development of Novel Silicon Pixel Detectors
Author: Maria Mironova
Publisher: Springer Nature
Total Pages: 206
Release: 2023-07-20
Genre: Science
ISBN: 3031362209

This book explores the Higgs boson and its interactions with fermions, as well as the detector technologies used to measure it. The Standard Model of Particle Physics has been a groundbreaking theory in our understanding of the fundamental properties of the universe, but it is incomplete, and there are significant hints which require new physics. The discovery of the Higgs boson in 2012 was a substantial confirmation of the Standard Model, but many of its decay modes remain elusive. This book presents the latest search for Higgs boson decays into c-quarks using a proton-proton collision dataset collected by the ATLAS experiment at the Large Hadron Collider (LHC). This decay mode has yet to be observed and requires advanced machine learning algorithms to identify c-quarks in the experiment. The results provide an upper limit on the rate of Higgs boson decays to c-quarks and a direct measurement of the Higgs boson coupling strength to c-quarks. The book also discusses the future of particle physics and the need for significant improvements to the detector to cope with increased radiation damage and higher data rates at the High-Luminosity LHC. It presents the characterization of the ATLAS pixel detector readout chip for the inner detector upgrade (ITk). The chip was subjected to irradiations using X-rays and protons to simulate the radiation environment at the HL-LHC. The tests showed that all readout chip components, including the digital logic and analogue front-end, are sufficiently radiation-tolerant to withstand the expected radiation dose. Finally, this book describes monolithic pixel detectors as a possible technology for future pixel detectors. This book is ideal for individuals interested in exploring particle physics, the Higgs boson, and the development of silicon pixel detectors.

Seeing the Light (Higgs)

Seeing the Light (Higgs)
Author: Khilesh Pradip Mistry
Publisher:
Total Pages: 498
Release: 2019
Genre:
ISBN:

This dissertation presents two results involving Standard Model Higgs bosons decaying to at least one photon. These analyses are performed using 79.8/fb-1 of proton-proton collisions collected at √s=13 TeV with the ATLAS detector at the Large Hadron Collider.

Search for Higgs Boson Decays to Beyond-the-Standard-Model Light Bosons in Four-lepton Events with the ATLAS Detector at the LHC.

Search for Higgs Boson Decays to Beyond-the-Standard-Model Light Bosons in Four-lepton Events with the ATLAS Detector at the LHC.
Author: Justin Chiu
Publisher:
Total Pages:
Release: 2020
Genre:
ISBN:

This thesis presents the search for the dark sector process h -> Zd Zd -> 4l in events collected by the ATLAS detector at the Large Hadron Collider in 2015--2018. In this theorized process, the Standard Model Higgs boson (h) decays to four leptons via two intermediate Beyond-the-Standard-Model particles each called Zd. This process arises from interactions of the Standard Model with a dark sector. A dark sector consists of one or more new particles that have limited or zero interaction with the Standard Model, such as the new vector boson Zd (dark photon). It could have a rich and interesting phenomenology like the visible sector (the Standard Model) and could naturally address many outstanding problems in particle physics. For example, it could contain a particle candidate for dark matter. In particular, Higgs decays to Beyond-the-Standard-Model particles are well-motivated theoretically and are not tightly constrained; current measurements of Standard Model Higgs properties permit the fraction of such decays to be as high as approximately 30%. The results of this search do not show evidence for the existence of the h -> Zd Zd -> 4l process and are therefore interpreted in terms of upper limits on the branching ratio B(h -> Zd Zd) and the effective Higgs mixing parameter kappa^prime.

A Novel Search for Exotic Decays of the Higgs Boson with the ATLAS Detector and Enhancing the Physics Potential of the Large Hadron Collider and Atom Interferometers with New Techniques

A Novel Search for Exotic Decays of the Higgs Boson with the ATLAS Detector and Enhancing the Physics Potential of the Large Hadron Collider and Atom Interferometers with New Techniques
Author: Murtaza Safdari
Publisher:
Total Pages: 0
Release: 2022
Genre:
ISBN:

Fundamental physics research aims to understand the theory of particle interactions, the Standard Model (SM) of particle physics being the current best theory of the electroweak and strong forces. Modern efforts seeks to explain phenomenon like the matter antimatter asymmetry of the universe and the nature of dark matter using various experimental modalities such as terrestrial particle colliders like the Large Hadron Collider (LHC). The ATLAS detector on the LHC is conducting a diverse physics program of precision SM measurements and searches for Physics beyond the SM using deeply inelastic scattering products to study fundamental physics. The original research presented here uses proton collision data from the ATLAS detector to search for an exotic decay mode of the Higgs boson coupling to a new light scalar field. Additionally, two research projects are presented to improve the performance of the ATLAS detector. The first introduces a novel algorithm to improve the efficiency of locating interesting physics within saved events. The second improves the jet calibration procedure by enabling the use of gradient based regression with a novel objective function along with a unified neural network based framework. Additionally, a network of quantum sensors are in development to enhance the physics reach of modern detectors and expand the set of models of new physics that can be experimentally probed. One such technology is atomic gradiometer interferometric sensors, like the MAGIS-100 experiment, that utilize matter waves to search for ultralight bosonic dark matter. The research and development of a novel light field imaging device is presented here for the MAGIS-100 experiment, as part of a burgeoning collaboration between the high energy physics (HEP) and the atomic, molecular, and optical (AMO) physics communities.