Search for the Associated Production of a W Boson and a Top Quark with the ATLAS Detector at 7 TeV

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ISBN 13 :
Total Pages : 173 pages
Book Rating : 4.:/5 (931 download)

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Book Synopsis Search for the Associated Production of a W Boson and a Top Quark with the ATLAS Detector at 7 TeV by :

Download or read book Search for the Associated Production of a W Boson and a Top Quark with the ATLAS Detector at 7 TeV written by and published by . This book was released on 2015 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for W' Boson with Boosted and Hadronic Top-quark Final State in Pp Collisions at 8́(s

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ISBN 13 :
Total Pages : 181 pages
Book Rating : 4.4/5 (711 download)

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Book Synopsis Search for W' Boson with Boosted and Hadronic Top-quark Final State in Pp Collisions at 8́(s by : Kuan-Yu Lin

Download or read book Search for W' Boson with Boosted and Hadronic Top-quark Final State in Pp Collisions at 8́(s written by Kuan-Yu Lin and published by . This book was released on 2021 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the LHC proton-proton collision data at an energy of 13 TeV recorded by the ATLAS detector, this analysis searches for the production of a new particle W' with a yet-to-be-probed mass in the top quark plus bottom quark decay channel. The boosted and hadronically decaying top-quark is reconstructed as a large-radius jet and identified using jet substructures. A secondary-vertex finding algorithm identifies small-radius jets originating from a bottom quark. After the identification stage, the main background events come from the Quantum Chromodynamical production of multi-jet, which is estimated by a data-driven approach. The statistical data analysis searches for a resonant peak in the invariant mass distribution of the system with a jet associated with the top quark and another with the bottom quark. The consistency between data and the background prediction is found in the invariant mass range between 1 TeV to 7 TeV, and an upper limit at the 95% confidence level is set on the production cross-section times branching ratio for a W' boson with right-handed chirality decaying to a top quark and a bottom quark. A lower limit on the W' mass is set at 4.4 TeV accordingly.

Search for Flavor-Changing Neutral Current Top Quark Decays t → Hq, with H → bb̅ , in pp Collisions at √s = 8 TeV with the ATLAS Detector

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Publisher : Springer
ISBN 13 : 3319634143
Total Pages : 248 pages
Book Rating : 4.3/5 (196 download)

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Book Synopsis Search for Flavor-Changing Neutral Current Top Quark Decays t → Hq, with H → bb̅ , in pp Collisions at √s = 8 TeV with the ATLAS Detector by : Shota Tsiskaridze

Download or read book Search for Flavor-Changing Neutral Current Top Quark Decays t → Hq, with H → bb̅ , in pp Collisions at √s = 8 TeV with the ATLAS Detector written by Shota Tsiskaridze and published by Springer. This book was released on 2017-08-02 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This PhD thesis focuses on the search for flavor-changing neutral currents in the decay of a top quark to an up-type quark (q = u, c) and the Standard Model Higgs boson, where the Higgs boson decays to bb. Further, the thesis presents the combination of this search for top quark pair events with other ATLAS searches – in the course of which the most restrictive bounds to date on tqH interactions were obtained. Following on from the discovery of the Higgs boson, it is particularly important to measure the Yukawa couplings of the Standard Model fermions; these parameters may provide crucial insights to help solve the flavor puzzle and may help reveal the presence of new physics before it is directly observed in experiments.

Search for New Phenomena in Top-Antitop Quarks Final States with Additional Heavy-Flavour Jets with the ATLAS Detector

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Publisher : Springer Nature
ISBN 13 : 9811509328
Total Pages : 279 pages
Book Rating : 4.8/5 (115 download)

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Book Synopsis Search for New Phenomena in Top-Antitop Quarks Final States with Additional Heavy-Flavour Jets with the ATLAS Detector by : Daiki Yamaguchi

Download or read book Search for New Phenomena in Top-Antitop Quarks Final States with Additional Heavy-Flavour Jets with the ATLAS Detector written by Daiki Yamaguchi and published by Springer Nature. This book was released on 2019-10-30 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on the search for a new heavy particle, the Vector-Like Top quark (VLT), in the Large Hadron Collider (LHC) at CERN. The signal process is the pair production of VLT decaying into a Higgs boson and top quark (TT→Ht+X, X=Ht, Wb, Zt). The signal events result in top–antitop quarks final states with additional heavy flavour jets. The book summarises the analysis of the data collected with the ATLAS detector in 2015 and 2016. In order to better differentiate between signals and backgrounds, exclusive taggers of top quark and Higgs boson were developed and optimised for VLT signals. These efforts improved the sensitivity by roughly 30%, compared to the previous analysis. The analysis outcomes yield the strongest constraints on parameter space in various BSM theoretical models. In addition, the book addresses detector operation and the evaluation of tracking performance. These efforts are essential to properly collecting dense events and improving the accuracy of the reconstructed objects that are used for particle identification. As such, they represent a valuable contribution to data analysis in extremely dense environments.

Search for New Heavy Charged Bosons and Measurement of High-Mass Drell-Yan Production in Proton—Proton Collisions

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Publisher : Springer
ISBN 13 : 3030006506
Total Pages : 386 pages
Book Rating : 4.0/5 (3 download)

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Book Synopsis Search for New Heavy Charged Bosons and Measurement of High-Mass Drell-Yan Production in Proton—Proton Collisions by : Markus Zinser

Download or read book Search for New Heavy Charged Bosons and Measurement of High-Mass Drell-Yan Production in Proton—Proton Collisions written by Markus Zinser and published by Springer. This book was released on 2018-09-25 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents two analyses, the first of which involves the search for a new heavy charged gauge boson, a so-called W' boson. This new gauge boson is predicted by some theories extending the Standard Model gauge group to solve some of its conceptual problems. Decays of the W' boson in final states with a lepton (l± = e± , μ±) and the corresponding (anti-)neutrino are considered. Data collected by the ATLAS experiment in 2015 at a center of mass energy of √s =13 TeV is used for the analysis. In turn, the second analysis presents a measurement of the double-differential cross section of the process pp->Z/gamma^* + X -> l^+l^- + X, including a gamma gamma induced contribution, at a center of mass energy of sqrt{s} = 8 TeV. The measurement is performed in an invariant mass region of 116 GeV to 1500 GeV as a function of invariant mass and absolute rapidity of the l^+l^-- pair, and as a function of invariant mass and pseudorapidity separation of the l^+l^-- pair. The data analyzed was recorded by the ATLAS experiment in 2012 and corresponds to an integrated luminosity of 20.3/fb. It is expected that the measured cross sections are sensitive to the PDFs at very high values of the Bjorken-x scaling variable, and to the photon structure of the proton.

Electroweak Physics at the LHC

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Publisher : Springer
ISBN 13 : 3319303813
Total Pages : 121 pages
Book Rating : 4.3/5 (193 download)

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Book Synopsis Electroweak Physics at the LHC by : Matthias U. Mozer

Download or read book Electroweak Physics at the LHC written by Matthias U. Mozer and published by Springer. This book was released on 2016-03-24 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book discusses the recent experimental results obtained at the LHC that involve electroweak bosons. The results are placed into an appropriate theoretical and historical context. The work pays special attention to the rising subject of hadronically decaying bosons with high boosts, documenting the state-of-the-art identification techniques and highlighting typical results. The text is not limited to electroweak physics in the strict sense, but also discusses the use of electroweak vector-bosons as tool in the study of other subjects in particle physics, such as determinations of the proton structure or the search for new exotic particles. The book is particularly well suited for graduate students, starting their thesis work on topics that involve electroweak bosons, as the book provides a comprehensive description of phenomena observable at current accelerators as well as a summary of the most relevant experimental techniques.

Search for Pair Production of a New B' Quark that Decays Into a Z Boson and a Bottom Quark with the ATLAS Detector at the LHC

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Publisher :
ISBN 13 :
Total Pages : 260 pages
Book Rating : 4.:/5 (839 download)

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Book Synopsis Search for Pair Production of a New B' Quark that Decays Into a Z Boson and a Bottom Quark with the ATLAS Detector at the LHC by : Andre Milton Bach

Download or read book Search for Pair Production of a New B' Quark that Decays Into a Z Boson and a Bottom Quark with the ATLAS Detector at the LHC written by Andre Milton Bach and published by . This book was released on 2012 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search with the ATLAS detector for the pair production of a new b' quark in the Z boson plus b quark decay channel is reported. The pp collision data comprise 4.7 fb-1 of integrated luminosity at sqrt(s) = 7 TeV collected at the CERN Large Hadron Collider in 2011. This search complements recent searches for a b' decaying to a W boson and a top quark, and it is particularly important for new physics models containing vector-like quarks. From events containing both a Z boson reconstructed from electrons and a b tagged jet, any potential signal is enriched by selecting a subsample with large b' candidate pT. No evidence for a b' signal is found in this subsample; the invariant mass spectrum of the b' candidate agrees well with the Standard Model prediction. For the case of a b' that decays only to Z + b, masses mb'

Search for New Physics in tt ̅ Final States with Additional Heavy-Flavor Jets with the ATLAS Detector

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Publisher : Springer
ISBN 13 : 3319410512
Total Pages : 288 pages
Book Rating : 4.3/5 (194 download)

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Book Synopsis Search for New Physics in tt ̅ Final States with Additional Heavy-Flavor Jets with the ATLAS Detector by : Javier Montejo Berlingen

Download or read book Search for New Physics in tt ̅ Final States with Additional Heavy-Flavor Jets with the ATLAS Detector written by Javier Montejo Berlingen and published by Springer. This book was released on 2016-07-20 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: This doctoral thesis focuses on the search for new phenomena in top-antitop quark (tt) final states with additional b-quark jets at the LHC. It uses the full Run 1 dataset collected by the ATLAS experiment in proton-proton collisions at √s=8 TeV. The final state of interest consists of an isolated lepton, a neutrino and at least six jets with at least four b-tagged jets, a challenging experimental signature owing to the large background from tt+heavy-flavor production. This final state is characteristic of ttH production, with the Higgs boson decaying into bb, a process that allows direct probing of the top-Higgs Yukawa coupling. This signature is also present in many extensions of the Standard Model that have been proposed as solutions to the hierarchy problem, such as supersymmetry or composite Higgs models, which predict the pair production of bosonic or fermionic top quark partners, or the anomalous production of four-top-quark events. All these physics processes have been searched for using an ambitious search strategy that has been developed on the basis of a combination of state-of-art theoretical predictions and a sophisticated statistical analysis to constrain in-situ the large background uncertainties. As a result, the most restrictive bounds to date on the above physics processes have been obtained.

Spin Correlations in tt Events from pp Collisions

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Publisher : Springer
ISBN 13 : 3319189328
Total Pages : 246 pages
Book Rating : 4.3/5 (191 download)

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Book Synopsis Spin Correlations in tt Events from pp Collisions by : Boris Lemmer

Download or read book Spin Correlations in tt Events from pp Collisions written by Boris Lemmer and published by Springer. This book was released on 2015-06-24 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis introduces readers to the Standard Model, the top quark and its properties, before explaining the concept of spin correlation measurement. The first measurement of top quark spin correlations at the LHC in the lepton+jets decay channel is presented. As the heaviest elementary particle, the top quark plays an essential role in the Standard Model of elementary particle physics. In the case of top quarks being produced in pairs at hadron colliders, the Standard Model predicts their spins to be correlated. The degree of correlation depends on both the production mechanism and properties of the top quark. Any deviation from the Standard Model prediction can be an indicator for new physics phenomena. The thesis employs an advanced top quark reconstruction algorithm including dedicated identification of the up- and down-type quarks from the W boson decay.

Measurement of the Associated Production of a Single Top Quark and a W Boson in Single-lepton Events with the ATLAS Detector

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (974 download)

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Book Synopsis Measurement of the Associated Production of a Single Top Quark and a W Boson in Single-lepton Events with the ATLAS Detector by : Sebastian Mergelmeyer

Download or read book Measurement of the Associated Production of a Single Top Quark and a W Boson in Single-lepton Events with the ATLAS Detector written by Sebastian Mergelmeyer and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for the Associated Production of the Higgs Boson with a Top Quark Pair in Multilepton Final States with the ATLAS Detector

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Publisher :
ISBN 13 :
Total Pages : 23 pages
Book Rating : 4.:/5 (94 download)

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Book Synopsis Search for the Associated Production of the Higgs Boson with a Top Quark Pair in Multilepton Final States with the ATLAS Detector by :

Download or read book Search for the Associated Production of the Higgs Boson with a Top Quark Pair in Multilepton Final States with the ATLAS Detector written by and published by . This book was released on 2015 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC

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Publisher : Springer Nature
ISBN 13 : 3030902064
Total Pages : 291 pages
Book Rating : 4.0/5 (39 download)

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Book Synopsis Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC by : Cristina Martin Perez

Download or read book Search for the Higgs Boson Produced in Association with Top Quarks with the CMS Detector at the LHC written by Cristina Martin Perez and published by Springer Nature. This book was released on 2022-02-09 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, the interaction between the Higgs boson and the top quark is studied with the proton-proton collisions at 13 TeV provided by the LHC at the CMS detector at CERN (Geneva). At the LHC, these particles are produced simultaneously via the associate production of the Higgs boson with one top quark (tH process) or two top quarks (ttH process). Compared to many other possible outcomes of the proton-proton interactions, these processes are very rare, as the top quark and the Higgs boson are the heaviest elementary particles known. Hence, identifying them constitutes a significant experimental challenge. A high particle selection efficiency in the CMS detector is therefore crucial. At the core of this selection stands the Level-1 (L1) trigger system, a system that filters collision events to retain only those with potential interest for physics analysis. The selection of hadronically decaying τ leptons, expected from the Higgs boson decays, is especially demanding due to the large background arising from the QCD interactions. The first part of this thesis presents the optimization of the L1 τ algorithm in Run 2 (2016-2018) and Run 3 (2022-2024) of the LHC. It includes the development of a novel trigger concept for the High-Luminosity LHC, foreseen to start in 2027 and to deliver 5 times the current instantaneous luminosity. To this end, sophisticated algorithms based on machine learning approaches are used, facilitated by the increasingly modern technology and powerful computation of the trigger system. The second part of the work presents the search of the tH and ttH processes with the subsequent decays of the Higgs boson to pairs of τ lepton, W bosons or Z bosons, making use of the data recorded during Run 2. The presence of multiple particles in the final state, along with the low cross section of the processes, makes the search an ideal use case for multivariant discriminants that enhance the selectivity of the signals and reject the overwhelming background contributions. The discriminants presented are built using state-of-the-art machine learning techniques, able to capture the correlations amongst the processes involved, as well as the so-called Matrix Element Method (MEM), which combines the theoretical description of the processes with the detector resolution effects. The level of sophistication of the methods used, along with the unprecedented amount of collision data analyzed, result in the most stringent measurements of the tH and ttH cross sections up to date.

Search for Standard Model Top Quark and Z Boson Associated Production at ATLAS

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Publisher :
ISBN 13 : 9781369179101
Total Pages : 122 pages
Book Rating : 4.1/5 (791 download)

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Book Synopsis Search for Standard Model Top Quark and Z Boson Associated Production at ATLAS by : Bradley D. Schoenrock

Download or read book Search for Standard Model Top Quark and Z Boson Associated Production at ATLAS written by Bradley D. Schoenrock and published by . This book was released on 2016 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for Scalar Top Quarks and Higgsino-Like Neutralinos

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Publisher : Springer
ISBN 13 : 9811000034
Total Pages : 229 pages
Book Rating : 4.8/5 (11 download)

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Book Synopsis Search for Scalar Top Quarks and Higgsino-Like Neutralinos by : Takuya Nobe

Download or read book Search for Scalar Top Quarks and Higgsino-Like Neutralinos written by Takuya Nobe and published by Springer. This book was released on 2015-11-30 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports a search for theoretically natural supersymmetry (SUSY) at the Large Hadron Collider (LHC). The data collected with the ATLAS detector in 2012 corresponding to 20 /fb of an integrated luminosity have been analyzed for stop pair production in proton–proton collisions at a center-of-mass energy of 8 TeV at the Large Hadron Collider (LHC) in the scenario of the higgsino-like neutralino. The author focuses on stop decaying into a bottom quark and chargino. In the scenario of the higgsino-like neutralino, the mass difference between charginos and neutralinos (Δm) is expected to be small, and observable final-state particles are likely to have low-momentum (soft). The author develops a dedicated analysis with a soft lepton as a probe of particles from chargino decay, which suppresses the large amount of backgrounds. As a result of the analysis, no significant SUSY signal is observed. The 95% confidence-level exclusion limits are set to masses of stop and neutralino assuming Δm = 20 GeV. The region with ΔM (the mass difference between stop and neutralino) 70 GeV is excluded for the first time at stop mass of less than 210 GeV. The author also excludes the signals with ΔM 120 GeV up to 600 GeV of stop mass with neutralino mass of less than 280 GeV. The author clearly shows very few remaining parameter spaces for light stop (e.g., topology of stop decay is extremely similar to the SM top quark) by combining his results and previous ATLAS analyses. His results provide a strong constraint to searches for new physics in the future.

Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like?

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Publisher : Frontiers Media SA
ISBN 13 : 2889639908
Total Pages : 180 pages
Book Rating : 4.8/5 (896 download)

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Book Synopsis Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like? by : Roman Pasechnik

Download or read book Phenomena Beyond the Standard Model: What Do We Expect for New Physics to Look Like? written by Roman Pasechnik and published by Frontiers Media SA. This book was released on 2020-09-03 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Standard Theory Of Particle Physics, The: Essays To Celebrate Cern's 60th Anniversary

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Publisher : World Scientific
ISBN 13 : 9814733520
Total Pages : 484 pages
Book Rating : 4.8/5 (147 download)

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Book Synopsis Standard Theory Of Particle Physics, The: Essays To Celebrate Cern's 60th Anniversary by : Luciano Maiani

Download or read book Standard Theory Of Particle Physics, The: Essays To Celebrate Cern's 60th Anniversary written by Luciano Maiani and published by World Scientific. This book was released on 2016-08-25 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'The editors make a good point in claiming the time has come to upgrade the Standard Model into the ‘Standard Theory’ of particle physics, and I think this book deserves a place in the bookshelves of a broad community, from the scientists and engineers who contributed to the progress of high-energy physics to younger physicists, eager to learn and enjoy the corresponding inside stories.'Carlos LourençoCERN CourierThe book gives a quite complete and up-to-date picture of the Standard Theory with an historical perspective, with a collection of articles written by some of the protagonists of present particle physics. The theoretical developments are described together with the most up-to-date experimental tests, including the discovery of the Higgs Boson and the measurement of its mass as well as the most precise measurements of the top mass, giving the reader a complete description of our present understanding of particle physics.

Theoretical Studies on Extended Higgs Sectors Towards Future Precision Measurements

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Publisher : Springer Nature
ISBN 13 : 9819913241
Total Pages : 268 pages
Book Rating : 4.8/5 (199 download)

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Book Synopsis Theoretical Studies on Extended Higgs Sectors Towards Future Precision Measurements by : Masashi Aiko

Download or read book Theoretical Studies on Extended Higgs Sectors Towards Future Precision Measurements written by Masashi Aiko and published by Springer Nature. This book was released on 2023-05-20 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book investigates the physics of the discovered Higgs boson and additional Higgs bosons in the extended Higgs models which includes higher-order quantum corrections. While the 125 GeV Higgs boson was discovered, the structure of the Higgs sector is still a mystery. Since the Higgs sector determines the concrete realization of the Higgs mechanism, the study of its nature is one of the central interests in current and future high-energy physics. The book begins with a review of the standard model and the two-Higgs doublet model, which is one of the representatives of the extended Higgs models. Subsequently, we discuss the studies of the two-Higgs doublet model at the lowest order of perturbation. Following the lowest-order analysis, we study the higher-order electroweak corrections in Higgs physics. After reviewing the renormalization procedure and the higher-order corrections in the decays of the discovered Higgs boson, we discuss the higher-order corrections in the Higgs strahlung process from an electron-positron collision, the decays of the additional charged and CP-odd Higgs bosons in the two-Higgs doublet model. From the series of these studies, it is found that the nature of the Higgs sector can be widely investigated by future collider experiments.