Academic literature on the topic 'Large Hadron Collider (LHC) - Higgs Boson'

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Journal articles on the topic "Large Hadron Collider (LHC) - Higgs Boson"

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BÜSCHER, VOLKER, and KARL JAKOBS. "HIGGS BOSON SEARCHES AT HADRON COLLIDERS." International Journal of Modern Physics A 20, no. 12 (May 10, 2005): 2523–602. http://dx.doi.org/10.1142/s0217751x05022457.

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The investigation of the dynamics responsible for electroweak symmetry breaking is one of the prime tasks of experiments at present and future colliders. Experiments at the Tevatron [Formula: see text] Collider and at the CERN Large Hadron Collider (LHC) must be able to discover a Standard Model Higgs boson over the full mass range as well as Higgs bosons in extended models. In this review, the discovery potential for the Standard Model Higgs boson and for Higgs bosons in the Minimal Supersymmetric extension is summarized. Emphasis is put on those studies which have been performed recently within the experimental collaborations using a realistic simulation of the detector performance. This includes a discussion of the search for Higgs bosons using the vector boson fusion mode at the LHC, a discussion of the measurement of Higgs boson parameters as well as a detailed review of the MSSM sector for different benchmark scenarios. The Tevatron part of the review also contains a discussion of first physics results from data taken in the ongoing Run II.
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BHATTACHARYA, SATYAKI. "Higgs Search with the Compact Muon Solenoid(CMS) detector at the Large Hadron Collider(LHC)." International Journal of Modern Physics A 20, no. 15 (June 20, 2005): 3400–3402. http://dx.doi.org/10.1142/s0217751x05026649.

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The Large Hadron Collider(LHC) is a proton proton collider being built at CERN, Geneva which will collide two 7 TeV proton beams giving a center of mass energy of 14 TeV. The Compact Muon Solenoid (CMS) is a multi-purpose detector at the LHC which is designed to discover the Higgs boson over the mass range of 90 to 1000 GeV. Since LEP searches have put a 95% C.L. lower bound on (standard model) Higgs mass of 114.4 GeV and theory excludes mass above about 1 TeV, CMS should discover the Higgs if it exists. In this paper, we will review CMS's Higgs-discovery potential both in the Standard Model and the Minimal Supersymmetric Standard Model for Higgs bosons produced in gluon-gluon fusion and in vector boson fusion mechanisms. Particular emphasis will be placed on discovery in the early years of running with luminosity of about 2 × 1033cm-2/s.
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JAKOBS, KARL, and MARKUS SCHUMACHER. "PROSPECTS FOR HIGGS BOSON SEARCHES AT THE LHC." International Journal of Modern Physics A 23, no. 32 (December 30, 2008): 5093–115. http://dx.doi.org/10.1142/s0217751x08042808.

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The investigation of the dynamics responsible for electroweak symmetry breaking is one of the prime tasks of experiments at the CERN Large Hadron Collider (LHC). The experiments ATLAS and CMS have been designed to be able to discover a Standard Model Higgs boson over the full mass range as well as Higgs bosons in extended models. In this paper, the prospects for Higgs boson searches at the LHC are reviewed. In addition, the potential for the measurement of Higgs boson parameters is discussed.
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AKKAYA, Gülistan. "Comparison Of Anomalous Higgs Couplings at the Large Hadron Collider and at Proton-Proton Collider with 100 TeV Energy." Bitlis Eren Üniversitesi Fen Bilimleri Dergisi 12, no. 2 (March 29, 2023): 396–401. http://dx.doi.org/10.17798/bitlisfen.1226395.

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Gammap and gammagamma ,called photon induced processes, have been examined in various colliders like Large Hadron Collider (LHC) and proton-proton collider with 100 TeV energy. One of the importance of these processes is that they allow for probing the anomalous Higgs couplings. The anomalous Higgs couplings constitute a testing ground for electroweak symmetry breaking (EWSB) mechanism and mass production system. For measuring anomalous Hgammagamma and HZgamma couplings at the LHC and at proton-proton collider with 100 TeV energy, the potential of the pp pgammap pHqX have been examined. Sensitivity bounds on anomalous Higgs couplings have been obtained at %95 confidence level. The analyses have been done for various integrated luminosities and for different scenarios Then the results of them have been compared. Model-independent effective Lagrangian technique have been used and the Higgs boson couplings to gauge bosons have been examined by dimension-six operators.
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TAYLOR, GEOFFREY N. "LOOKING FORWARD TO THE LARGE HADRON COLLIDER." International Journal of Modern Physics A 22, no. 27 (October 30, 2007): 5039–51. http://dx.doi.org/10.1142/s0217751x07038396.

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In this paper an overview of the Large Hadron Collider program and status is given, including a brief description of the scientific background from which this ambitious program evolved. The emphasis is on the status of the Standard Model Higgs Boson, searches for which are the key component of the LHC program. A description of the ATLAS one of the two large general purpose experiments designed to detect evidence for the Higgs Boson and other data of interest to searches for physics beyond the standard model.
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Khosa, Charanjit K., and P. N. Pandita. "Measuring the trilinear neutral Higgs boson couplings in the minimal supersymmetric standard model at e+e− colliders in the light of the discovery of a Higgs boson." International Journal of Modern Physics A 31, no. 18 (June 29, 2016): 1650108. http://dx.doi.org/10.1142/s0217751x16501086.

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We consider the measurement of the trilinear couplings of the neutral Higgs bosons in the minimal supersymmetric standard model (MSSM) at a high energy [Formula: see text] linear collider in the light of the discovery of a Higgs boson at the CERN Large Hadron Collider (LHC). We identify the state observed at the LHC with the lightest Higgs boson [Formula: see text] of the MSSM, and impose the constraints following from this identification, as well as other experimental constraints on the MSSM parameter space. In order to measure trilinear neutral Higgs couplings, we consider different processes where the heavier Higgs boson [Formula: see text] of the MSSM is produced in electron–positron collisions, which subsequently decays into a pair of lighter Higgs boson. We identify the regions of the MSSM parameter space where it may be possible to measure the trilinear couplings of the Higgs boson at a future electron–positron collider. A measurement of the trilinear Higgs couplings is a crucial step in the construction of the Higgs potential, and hence in establishing the phenomena of spontaneous symmetry breaking in gauge theories.
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Nisati, Aleandro. "The Discovery of a Higgs Particle at the Large Hadron Collider." European Review 23, no. 1 (January 29, 2015): 57–70. http://dx.doi.org/10.1017/s1062798714000544.

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The Large Hadron Collider (LHC) at CERN is the highest energy machine for particle physics research ever built. In the years 2010–2012 this accelerator has collided protons to a centre-mass-energy up to 8 TeV (note that 1 TeV corresponds to the energy of about 1000 protons at rest; the mass of one proton is about 1.67×10–24 g). The events delivered by the LHC have been collected and analysed by four apparatuses placed alongside this machine. The search for the Higgs boson predicted by the Standard Model and the search for new particles and fields beyond this theory represent the most important points of the scientific programme of the LHC. In July 2012, the international collaborations ATLAS and CMS, consisting of more than 3000 physicists, announced the discovery of a new neutral particle with a mass of about 125 GeV, whose physics properties are compatible, within present experimental and theoretical uncertainties, to the Higgs boson predicted by the Standard Model. This discovery represents a major milestone for particle physics, since it indicates that the hypothesized Higgs mechanism seems to be responsible for the masses of elementary particles, in particular W± and Z0 bosons, as well as fermions (leptons and quarks). The 2013 Physics Nobel Prize has been assigned to F. Englert and P. Higgs, ‘for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider’.
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Horváth, Dezső. "Twenty years of searching for the Higgs boson: Exclusion at LEP, discovery at LHC." Modern Physics Letters A 29, no. 04 (February 10, 2014): 1430004. http://dx.doi.org/10.1142/s0217732314300043.

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The 40 years old Standard Model, the theory of particle physics, seems to describe all experimental data very well. All of its elementary particles were identified and studied apart from the Higgs boson until 2012. For decades, many experiments were built and operated searching for it, and finally, the two main experiments of the Large Hadron Collider (LHC) at CERN, CMS and ATLAS, in 2012 observed a new particle with properties close to those predicted for the Higgs boson. In this paper, we outline the search story: the exclusion of the Higgs boson at the Large Electron Positron (LEP) collider, and its observation at LHC.
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Dissertori, G. "The pre-LHC Higgs hunt." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, no. 2032 (January 13, 2015): 20140039. http://dx.doi.org/10.1098/rsta.2014.0039.

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Enormous efforts at accelerators and experiments all around the world have gone into the search for the long-sought Higgs boson, postulated almost five decades ago. This search has culminated in the discovery of a Higgs-like particle by the ATLAS and CMS experiments at CERN's Large Hadron Collider in 2012. Instead of describing this widely celebrated discovery, in this article I will rather focus on earlier attempts to discover the Higgs boson, or to constrain the range of possible masses by interpreting precise data in the context of the Standard Model of particle physics. In particular, I will focus on the experimental efforts carried out during the last two decades, at the Large Electron Positron collider, CERN, Geneva, Switzerland, and the Tevatron collider, Fermilab, near Chicago, IL, USA.
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Davy, Manyika Kabuswa, Likolo Anabiwa George, and Katongo Judith. "On the synopsis of the Higgs boson." Physics & Astronomy International Journal 7, no. 2 (May 12, 2023): 113–16. http://dx.doi.org/10.15406/paij.2023.07.00294.

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In this paper, we analyze the Standard Model (SM) Higgs boson by computing both the partial width and the amplitude of a number of decay channels that the Higgs Boson can undergo. In our computations, we treat the Higgs boson as a free parameter despite its estimated mass of around 125GeV discovered at the Large Hadron Collider (LHC).
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Dissertations / Theses on the topic "Large Hadron Collider (LHC) - Higgs Boson"

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Sekmen, Sezen. "Higgs Formation At The Black Hole Decays At Large Hadron Collider." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1106780/index.pdf.

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This thesis examines the possible creation of (4+n)-dimensional black holes at Large Hadron Collider (LHC) at CERN, consequent decays of such black holes via Hawking radiation and probable formation of Higgs boson among black hole decay products. Firstly, a theoretical background was presented including black hole physics, Hawking radiation, large extra dimensions, brane-bulk models, 4+n black holes and Higgs mechanism. Then, a simulation modeling black hole formation and decay including 130 GeV Higgs as a decay product at LHC interfaced with a detector simulation of Compact Muon Selenoid (CMS) was analysed focusing especially on the Higgs decay channels and properties of Hawking radiation. Both theoretical assumptions and simulation analysis point out that black hole production and the signatures of black hole decay products could carry crucial information on dimensionality and structure of spacetime Furthermore there is a significant possibility to observe 130 GeV Higgs boson especially in the Black Hole ->
H ->
jj and Black Hole ->
H &
#8211
>
WW/ZZ ->
lnln decay channels.
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Glaysher, Paul Christopher Frederick. "Differential cross section measurements in H→ WW and prospects of observing H→ bb in future LHC runs at the ATLAS detector." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/22074.

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The highly celebrated discovery of a new particle with a mass of 125 GeV in proton-proton collisions by the ATLAS and CMS experiments at the CERN Large Hadron Collider in 2012 has been shown to be compatible with the Standard Model description of the Higgs boson. However, in order to fully verify the Standard Model nature of the Higgs boson, most of its properties still remain to be measured. Such measurements include differential cross section measurements, which are shown here for the H→WW decay channel and the coupling of the Higgs boson to bottom quarks, for which a study of future prospects is presented. Differential fiducial cross section measurements of the Higgs boson were performed in the H → WW*→lvlv channel at the ATLAS detector with 20 fb−1 of √s = 8 TeV collision data. For Higgs bosons produced by gluon-gluon fusion, the cross section is measured as a function of kinematic variables, including transverse momentum and rapidity of the Higgs boson, as well as the number of jets associated with the Higgs event. The obtained distributions are unfolded to a fiducial volume using a two-dimensional iterative Bayesian algorithm. The measured fiducial differential cross sections are compared to predictions from Monte Carlo generators. The total cross section measured in the fiducial volume defined by the charged lepton and neutrino kinematic properties is 36.0 ± 9.7 fb. Additionally the jet-veto efficiency in the fiducial volume is extracted from the differential cross sections. An analysis is presented of Higgs boson production and decay into bottom quarks in association with a vector boson at the ATLAS detector for the future high-luminosity LHC with proton-proton collisions at √s = 14 TeV. The vector bosons are reconstructed from Z→l+l− or W→lv final states, where l is an electron or muon. The analysis uses generator-level Monte Carlo samples to which efficiency and resolution smearing functions are applied. These reproduce the expected resolution of the upgraded ATLAS detector for the foreseen amount of pile-up due to multiple overlapping proton-proton collisions. The analysis of the ZH(→ l+l−b¯b) channel is presented and results are combined with the WH(→lvb¯b) channel from a corresponding study. For an integrated luminosity of 300 fb−1 using an average pile-up of 60, the expected significance is 3.9 σ with an expected error on the signal strength of 25%. Likewise, for 3000 fb−1 using an average pileup of 140 the expected significance is 8.8 σ , and the error on the signal strength is expected to be about 15%.
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Garay, Francisca Montserrat. "Studies of the Higgs boson using the H → ZZ → 4l decay channel with the ATLAS detector at the LHC." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25382.

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Following the announcement of the discovery of a new particle on the 4th of July 2012 at the ATLAS and CMS experiments at the LHC, many efforts were needed for the understanding of its properties and to discern whether it is the Standard Model Higgs boson. The research presented in this thesis is based on the H → ZZ(*) → 4l decay channel. Three main contributions are discussed: the Standard Model Higgs boson mass measurement, the search for a heavy Higgs boson, and lastly, the implementation of a kinematic likelihood fitter as a new approach to improve the invariant mass resolution of the final states. The Standard Model Higgs boson mass measurement is presented. The measured mass is 124:51± 0:52(stat)± 0:06(syst) GeV for the combined data taken during 2011 and 2012 (4:6 fb-¹ at 7 TeV and 20:7 fb-¹ at 8 TeV). Contributing to the mass measurement, a tool was developed to validate the model used by generating several pseudo datasets from Monte Carlo samples and fitting them with the profile likelihood. The results show that the model is correct and only small deviations are seen in the parameters of interest, mH, and the signal strength, μ. Studies in the asymptotic limit show that these deviations are a symptom of low statistics in some of the final states. The search for a heavy Higgs boson is presented as well. No significant excess of events over the Standard Model prediction is found. A simultaneous fit to the profile likelihood gives 95% confidence level upper limits on the production cross-section of a heavy Higgs times the branching ratio to Z boson pairs in the mass range from 140 GeV to 1 TeV. Contributing to this search, a pseudo dataset, called Asimov dataset, is created from the Monte Carlo samples to test the profile likelihood fits and validate the model used. The results show that fit the model is correct. In addition, the limits are also interpreted in the context of Type I and Type II Two Higgs Doublet Models (2HDM). Finally, a Kinematic Likelihood Fitter (KLFitter) is studied and used to constrain the Z boson mass as an alternative to the standard tool used for the 2011 and 2012 measurement. This affects the distribution of the invariant mass, m4l, from which the Higgs boson mass is inferred. Small improvements are seen in the invariant mass resolution when higher hypothetical Higgs boson masses are considered.
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Bristow, Timothy Michael. "Search for the Higgs boson decaying to bottom quarks and W boson tagging techniques at the ATLAS experiment at the LHC." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25393.

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The Standard Model of particle physics is currently the most complete theory of subatomic particles. The discovery of the Higgs boson with a mass of 125 GeV in 2012 further validated the Standard Model, providing evidence for the theory that vector bosons obtain non-zero masses through the Higgs mechanism. Studies are ongoing to determine the exact nature and properties of the Higgs boson. A Higgs boson of this mass is predicted to decay to a pair of b-b quarks with a branching ratio of 58%, however this decay mode has not yet been observed. This thesis presents a search for the associated production of a Higgs boson with a leptonically decaying W boson, WH → ℓvb-b, using 20.3 fb-1 of Run 1 data collected by ATLAS at the LHC from pp collisions at a centre-of-mass energy of ps = 8 TeV. The observed (expected) significance of a Higgs boson with a mass of 125 GeV for the WH → ℓvb-b process is found to be 2:7σ (1:3σ). The measured cross section in units of the expected Standard Model cross section has a best-fit value of μ = μ/μSM = 2:2+0:67-0:64(stat:)+0:7-0:59(syst:) = 2:2+0:97-0:87. The results are combined with the search for ZH → v-vb-b and ZH → ℓ+ℓ-b-b to provide a best-fit value of μ = μ/μSM = 1:1+0:61-0:56. The start of Run 2 of the LHC in 2015 saw the collision energy being raised to √s = 13 TeV, increasing the probability of particles being produced with a large momentum boost. At these high energies there is also a possibility to discover new particles and interactions. An extension of the Standard Model, the Heavy Vector Triplet (HVT) model, describes new heavy vector bosons W¹ and Z¹, which can decay to pairs of heavy bosons (W, Z or Higgs bosons). If the W0 and Z0 bosons are sufficiently heavy, the hadronic decays of the diboson final states produce boosted jets. In this thesis, methods for identifying hadronically decaying boosted bosons are developed, based on techniques that examine the internal substructure of the jet. Multiple substructure variables are combined into a single discriminant using two machine learning techniques: boosted decision trees and deep neural networks. Simulated events of W¹→WZ → q-qq-q are used to develop these boosted W boson taggers. An improvement in the background rejection power, whilst keeping 50% of the signal, over previous boosted W boson taggers of up to 13%-when using deep neural networks-and 36%-when using boosted decision trees-is obtained. The performance of the new boosted W boson taggers are evaluated in a search for a narrow WW resonances from the decay of a Z¹ with boson-tagged jets in 3.2 fb-1 of pp collisions at √s = 13 TeV collected with the ATLAS detector.
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Anger, Philipp. "Probing Electroweak Gauge Boson Scattering with the ATLAS Detector at the Large Hadron Collider." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-151612.

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Electroweak gauge bosons as central components of the Standard Model of particle physics are well understood theoretically and have been studied with high precision at past and present collider experiments. The electroweak theory predicts the existence of a scattering process of these particles consisting of contributions from triple and quartic bosonic couplings as well as Higgs boson mediated interactions. These contributions are not separable in a gauge invariant way and are only unitarized in the case of a Higgs boson as it is described by the Standard Model. The process is tied to the electroweak symmetry breaking which introduces the longitudinal modes for the massive electroweak gauge bosons. A study of this interaction is also a direct verification of the local gauge symmetry as one of the fundamental axioms of the Standard Model. With the start of the Large Hadron Collider and after collecting proton-proton collision data with an integrated luminosity of 20.3/fb at a center-of-mass energy of 8 TeV with the ATLAS detector, first-ever evidence for this process could be achieved in the context of this work. A study of leptonically decaying WWjj, same-electric-charge diboson production in association with two jets resulted in an observation of the electroweak WWjj production with same electric charge of the W bosons, inseparably comprising WW->WW electroweak gauge boson scattering contributions, with a significance of 3.6 standard deviations. The measured production cross section is in agreement with the Standard Model prediction. In the course of a study for leptonically decaying WZ productions, methods for background estimation, the extraction of systematic uncertainties and cross section measurements were developed. They were extended and applied to the WZjj final state whereof the purely electroweakly mediated contribution is intrinsically tied to the scattering of all Standard Model electroweak gauge bosons: Wγ->WZ and WZ->WZ. Three charged leptons and a neutrino from the decay of the final state bosons allow inferences about the scattering process. A distinct signature is provided by the two accompanying tagging jets as remnants of the incoming quarks radiating the initial electroweak gauge bosons. The cross section of the electroweak WZjj production was measured to σ(fiducial, observed) = (0.63 +0.32 -0.28 (stat.) +0.41 -0.24 (syst.)) fb and was found to be consistent with the Standard Model prediction at next-to-leading order in perturbative quantum chromodynamics, σ(fiducial, theory) = (0.31 +0.03 -0.05) fb. Unfolded differential cross sections of kinematic variables sensitive to models of new physics were derived. Anomalous quartic electroweak gauge couplings are introduced as dimensionless coupling parameters of additional operators within an effective field theory approach. Constraints on the parameters of operators with dimension eight were set employing a unitarization prescription based on form factors.
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Descamps, Julien. "Etude et optimisation des performances du calorimètre électromagnétique de l'expérience CMS pour la physique au LHC." Paris 6, 2007. http://www.theses.fr/2007PA066136.

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L’expérience CMS (Compact Muon Solenoid) est l’une des deux expériences généralistes du collisionneur proton-proton LHC (Large Hadron Collider) actuellement en cours de démarrage au CERN à Genève. Les premiers chapitres de cette thèse présentent le LHC, le détecteur CMS et plus particulièrement son calorimètre électromagnétique (ECAL). Est présentée ensuite une analyse des tests réalisés en 2004 avec un faisceau d’électrons de différentes énergies (20-250 GeV) dirigé vers une partie (1/36) du baril du calorimètre. Une étude de la variation de la mesure de l’énergie a été menée afin de déduire une méthode de correction. Le dernier chapitre de cette thèse présente une application de cette méthode de correction aux électrons et aux photons engendrés par une simulation complète de CMS dans laquelle la reconstruction de l’énergie est considérablement compliquée par rapport à la configuration des tests en faisceau. Un algorithme novateur de reconstruction de l’énergie des électrons et des photons a été développé pour tenir compte de cette complication et appliquer la méthode de correction étudiée en tests en faisceau.
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Dar, Shahida. "TeV scale leptogenesis, primordial monopoles, and supersymmetry at LHC." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 129 p, 2008. http://proquest.umi.com/pqdweb?did=1601522291&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Perego, Marta Maria. "Search for new physics produced via Vector Boson Fusion in final states with large missing transverse momentum with the ATLAS detector." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS088/document.

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Cette thèse présente des recherches sur la nouvelle physique produite par le processus de Fusion de Bosons Vecteur (VBF) dans les états finaux avec une grand impulsion transverse manquante (Etmiss) en utilisant 36.1 fb⁻¹ de données de collisions proton-proton avec une énergie dans le centre de masse de 13 TeV, recueillies par l'expérience ATLAS au Large Hadron Collider (LHC) au CERN en 2015 et 2016. En particulier, elle se concentre sur la recherche de la désintégration invisible du boson de Higgs produit via le mode VBF. Comme le modèle standard de la physique des particules (MS) prédit une désintégration invisible de Higgs uniquement à travers le mode H->ZZ*->4v avec un rapport d’embranchement BR ~ 0,1%, si une désintégration en particules invisibles du boson de Higgs était observée avec un BR supérieur, ce serait un signe de nouvelle physique. Plusieurs modèles au-delà du modèle standard (BSM) prédisent des désintégrations du boson de Higgs en particules de matière noire (DM, non détectées) ou en particules massives neutres à vie longue. Parmi les recherches H->particules invisibles, la plus sensible est celle où le Higgs est produit via le mode VBF. Son état final est caractérisé par deux jets énergétiques, avec les caractéristiques typiques du mode VBF (c'est-à-dire une grande séparation angulaire et une grande masse invariante des deux jets) et une grande impulsion transverse manquante (Etmiss>180 GeV). Pour sélectionner un échantillon d'événements candidats de signal, une région de signal (SR) est définie pour maximiser la fraction d'événements de signal attendus par rapport à la prédiction du MS (bruit de fond). Les processus MS qui peuvent peupler la SR proviennent principalement des processus Z->vv+jets et W->lv+jets, où le lepton est perdu ou non reconstruit. Leur contribution est estimée avec une approche semi-data driven : des régions dédiées enrichies en événements W->lv/Z->ll sont utilisées pour normaliser les données des estimations de Monte Carlo (MC) en utilisant une technique de fit simultané (méthode du facteur de transfert) et pour les extrapoler à la SR. L'estimation de fond prédit est comparée aux données SR observées. Comme aucun excès n'est trouvé, une limite supérieure sur le BR (H-> invisible) est calculée. L'analyse est ensuite réinterprétée dans le cadre de modèles inspirés du modèle Minimal Dark Matter. Le cas d'un nouveau triplet fermionique électrofaible, avec une hypercharge nulle et avec interactions respectant le nombre B-L, ajouté au MS fournit un bon candidat Dark Matter (WIMP pure). Si on considère l'abondance thermique, la masse du composant neutre est d’environ 3 TeV. Cependant des masses plus faibles sont également envisageables dans le cas de mécanismes de production non thermiques ou lorsque le triplet ne constitue qu'une fraction de l'abondance de DM. Il peut être produit à des collisionneurs proton-proton tels que le LHC et il peut être sondé de différentes manières. Une fois produites, les composantes chargées du triplet se désintègrent dans le composant neutre le plus léger, χ0 , avec en plus des pions très mous, en raison de la petite différence de masse entre les composants neutres et chargés. Ces pions de très faible impulsion ne peuvent pas être reconstruits et sont donc perdus. Le χ0 est reconstruit comme de l’Etmiss dans le détecteur. Par conséquent, lorsqu'il est produit via VBF, il donne lieu à une signature avec deux jets VBF et de l’Etmiss, le même état final que celui qui a été étudié pour l'analyse de VBF H->invisible. Des points de masse différentes (de 90 GeV à 200 GeV) ont été engendrés avec les programmes Monte Carlo Madgraph+Pythia, dans le cadre du logiciel officiel ATLAS, et les limites supérieures sont définies sur la section efficace fiducielle de production. Des extrapolations à des luminosités plus élevées (Run3 et HL-LHC) en utilisant une approche simplifiée sont également présentées
This thesis presents searches for new physics produced via Vector Boson Fusion (VBF) in final states with large Missing Transverse Momentum (Etmiss) using 36.1 fb⁻¹ of data from proton-proton collisions at center-of-mass-energy of 13 TeV, collected by the ATLAS experiment at the Large Hadron Collider at CERN during 2015 and 2016. In particular, it focuses on the search for the invisible decay of the Higgs boson produced via the vector boson fusion (VBF) process. As the SM predicts an Higgs invisible decay only through H->ZZ*->4v with Branching Ratio BR~0.1%, if an invisibly decaying Higgs boson would be observed with a higher BR, this would be a sign of new physics. Several Beyond the Standard Model (BSM) models predict invisibly decaying Higgs boson where the Higgs can decay into dark matter particles or neutral long-lived massive particles. Among the H->invisible searches the most sensitive one is the one where the Higgs is produced via the VBF process. Its final state is characterized by two energetic jets, with the typical features of the VBF mode (i.e. large angular separation and large invariant mass) and large missing transverse momentum (Etmiss>180 GeV). To select a sample of signal candidate events, a Signal Region (SR) is designed to maximize the fraction of expected signal events with respect to the SM prediction (backgrounds). The SM processes which can populate the SR comes mainly from Z->vv+jets and W->lv+jets processes, where the lepton is lost or not reconstructed. Their contribution is estimated with a semi data driven approach: dedicated regions enriched in W->lv/Z->ll events are used to normalize to data the Monte Carlo (MC) estimates using a simultaneous fitting technique (transfer factor) and to extrapolate them to the SR. The predicted background estimate is compared to the observed SR data. Since no excess is found, an upper limit on the BR(H->inv) is set. The analysis is then reinterpreted in the context of models inspired by the Minimal Dark Matter model. The case of a new electroweak fermionic triplet, with null hypercharge and with interactions respecting the B-L number, added on top of the SM provides a good Dark Matter candidate. As such, it is an example of pure Weakly Interacting Massive Particle (WIMP), meaning that it is a DM particle with SU(2)_L SM interactions which is not mixing with other states (pure).If the thermal abundance is assumed, the mass of the neutral component is around 3 TeV, however smaller masses are also allowed in case of non-thermal production mechanisms or if the triplet constitutes only a fraction of the DM abundance. It can be produced at proton-proton colliders such as the LHC and it can be probed in different ways. Once produced, the charged components of the triplet decays into the lightest neutral component chi0 plus very soft charged pions. chi0 is reconstructed as Etmiss in the detector while the pions, because of the small mass splitting between the neutral and charged components, are so soft that are lost and are not reconstructed. Therefore, when produced via VBF, it gives rise to a signature with two VBF jets and Etmiss, the same final state that has been investigated for the VBF Higgs invisible analysis. Different mass point (from 90 GeV to 200 GeV) have been generated with the Madgraph+Pythia, Monte Carlo programs within the official ATLAS software, and upper limits are set on the fiducial cross section. Extrapolations to higher luminosities using a simplified approach are also presented
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Portillo, Quintero Dilia María. "Recherche de la matière sombre produite en association avec un boson de Higgs se désintégrant dans une paire de quark b avec le détecteur ATLAS." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS208.

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Une recherche de la production de matière noire associée à un boson de Higgs se décomposant en b-quarks est effectuée à l'aide de collisions pp à une énergie de centre de masse de √s = 13 TeV. L'ensemble de données a une luminosité intégrée de 80fb − 1 et a été enregistré avec le détecteur ATLAS du grand collisionneur de hadrons. Les événements de collision sélectionnés comprennent un grand moment transversal manquant et deux jets à petit rayon marqués b ou un seul jet à grand rayon contenant deux sujets marqués b. L'identification de ces sujets est basée sur un algorithme de jet dans lequel le paramètre de rayon est réduit à mesure que le moment transversal augmente. De plus, avec l'aide d'une nouvelle technique de reconstruction, l'absence de signification de la quantité de mouvement transversale manquante basée sur les objets, il est démontré que le fond provenant d'interactions fortes pures peut être rejeté avec succès. Les résultats sont interprétés dans le contexte d'un modèle simplifié (Z′-2HDM) décrivant l'interaction de la matière noire et des particules du modèle standard via de nouvelles particules lourdes de médiateur. Des limites indépendantes du modèle sur la section transversale de référence pour la production manquante de quantité de mouvement transverse de Higgs + sont également fournies
A search for dark matter production in association with a Higgs boson decaying to b-quarks is performed using pp collisions at a centre-of-mass energy of √s=13TeV. The dataset has an integrated luminosity of 80fb−1 and was recorded with the ATLAS detector at the Large Hadron Collider. Selected collision events comprise large missing transverse momentum and either two b-tagged small radius jets or a single large radius jet containing two b-tagged subjets. The identification of these subjects is based on a jet algorithm where the radius parameter is shrinked as the transverse momentum increases. Also, with the help of a novel reconstruction technique, the object-based missing transverse momentum significance, it is shown that background coming from pure strong interactions can be successfully rejected. The results are interpreted in the context of a simplified model (Z′-2HDM) which describes the interaction of dark matter and standard model particles via new heavy mediator particles. Also model independent limits on the fiducial cross-section for Higgs + missing transverse momentum production are provided
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González, Fraile Juan. "On the origin of masses at the LHC." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/284218.

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In this thesis we present several studies on the origin of masses at the LHC. First we study the indirect effects of new physics on the couplings of the recently discovered Higgs boson and on the electroweak symmetry breaking (EWSB) sector interactions. In a model independent framework these effects can be parametrized in terms of an effective Lagrangian at the electroweak scale. In the first Chapter we present the effective Lagrangian description based on the linear realization of the electroweak symmetry, where the Higgs particle is assumed to be part of an SU(2)L doublet. We discuss a choice of dimension–six operators guided by the existing data, and we study the phenomenology of the operators. We perform a global analysis to the existing Higgs, triple gauge boson vertex and electroweak precision data, coming from LHC, Tevatron, LEP and low energy observables. Finally we exploit the interesting complementarity between the studied Higgs and triple gauge boson vertex measurements in order to test the linear realization. In the second Chapter we present two alternative Lagrangian descriptions. First, we study the non–linear or chiral effective Lagrangian, where now the Higgs is not part of an SU(2)L doublet. We describe the chiral operators and, while focusing on the phenomenological di.erences with respect to the linear realization, we also perform the first global analysis of the non–linear basis. Second, we present the Lagrangian parametrization commonly used to measure and describe the triple gauge boson vertex WWZ. We perform a collider analysis where we optimize the LHC capability to measure this vertex, obtaining an impressive LHC potential to improve the current sensitivity on anomalous interactions. We focus on their relation with the disentanglement of the Higgs nature. In the second part of the thesis we study the origin of masses at the LHC by the direct exploration of new resonances related to several beyond the Standard Model descriptions. In the third Chapter we study new vector resonances that couple to electroweak gauge boson pairs, which are common resonances on several EWSB extensions of the Standard Model. We analyze the LHC potential to determine the spin of these resonances, and furthermore we use the present available LHC public analyses to constrain the existence of the new neutral vector resonances, Z’, obtaining the strongest exclusion bounds on their existence. In the last Chapter we analyze the LHC potential to access the mechanism related to the origin of the neutrino masses. We study the different characteristics of a model that, while generating the observed pattern of neutrino masses and mixing, can lead to observable TeV signatures. We describe the phenomenology of the model and the new heavy leptons that are introduced, to finally optimize and analyze the LHC potential to observe these new partners, finding again very promising results.
En esta tesis presentamos varios estudios sobre el origen de masas en el LHC. Primero estudiamos los efectos indirectos de nueva física en las interacciones del recientemente descubierto bosón de Higgs y del resto del sector de rotura de la simetría electrodébil. Independientemente del modelo estos efectos se pueden caracterizar por medio de Lagrangianos efectivos en la escala electrodébil. En el primer Capítulo presentamos el Lagrangiano efectivo en la realización lineal de la simetría, donde la partícula de Higgs se introduce como parte de un doblete de SU(2)L. Describimos una elección de la base de operadores de dimensión–seis guiada por los datos existentes y estudiamos la fenomenología de los operadores. Realizamos un análisis global con todos los datos existentes de producción del Higgs, de medidas del vértice triple de bosones de gauge y de medidas de alta precisión electrodébiles, que provienen de LHC, Tevatron, LEP y otras observaciones a bajas energías. Finalmente estudiamos cómo la complementariedad entre las medidas de las interacciones del Higgs y del vértice con tres bosones de gauge sirve para testear la realización lineal. En el segundo Capítulo presentamos dos Lagrangianos alternativos. Primero el Lagrangiano efectivo no–lineal o quiral, donde ahora el bosón de Higgs no es parte de un doblete de SU(2)L. Describimos los operadores quirales, centrándonos en las diferencias fenomenológicas respecto a la expansión lineal y, además, realizamos el primer análisis global en la base quiral. En segundo lugar describimos el Lagrangiano utilizado históricamente para estudiar el vértice WWZ. Realizamos un análisis optimizando el potencial del LHC para medir anomalías en este vértice, obteniendo previsiones que superan la precisión actual. En la segunda parte de la tesis estudiamos el origen de masas en el LHC buscando directamente nuevas resonancias relacionadas con extensiones del modelo estándar. En el tercer Capítulo analizamos resonancias vectoriales que interaccionan con pares de bosones de gauge electrodébiles, estados comunes en varias extensiones teóricas que explican la rotura de la simetría electrodébil. Estudiamos primero el potencial del LHC para determinar el espín de estas nuevas partículas y después utilizamos los datos públicos disponibles del LHC para constreñir la existencia de nuevas resonancias vectoriales neutras, Z’, obteniendo los límites más fuertes sobre su existencia. En el último capítulo analizamos el potencial que tiene el LHC para acceder al mecanismo relacionado con el origen de las masas de los neutrinos. Estudiamos las características de un modelo que consigue explicar el patrón de masas y mezclas observado para los neutrinos, dando lugar a la vez a nuevas señales en la escala del TeV. Describimos la fenomenología del modelo y de los nuevos leptones pesados que se introducen, para .nalmente analizar la capacidad que tiene el LHC para observar estos estados, dando lugar, otra vez, a resultados muy prometedores.
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Books on the topic "Large Hadron Collider (LHC) - Higgs Boson"

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Davier, M. LHC: Le boson de Higgs. Paris: le Pommier, 2013.

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Electroweak physics at LEP and LHC. Heidelberg [Germany]: Springer, 2010.

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The Large Hadron Collider and Higgs boson research. Hauppauge, N.Y: Nova Science Publishers, 2011.

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Wolf, Roger. The Higgs Boson Discovery at the Large Hadron Collider. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-18512-5.

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Smashing physics. London: Headline, 2014.

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Inside CERN's Large Hadron Collider: From the proton to the Higgs boson. Singapore: World Scientific, 2015.

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Sarica, Ulascan. Measurements of Higgs Boson Properties in Proton-Proton Collisions at √s =7, 8 and 13 TeV at the CERN Large Hadron Collider. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-25474-2.

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Campbell, John, Joey Huston, and Frank Krauss. The Black Book of Quantum Chromodynamics. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199652747.001.0001.

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The LHC (Large Hadron Collider) will serve as the energy frontier for high-energy physics for the next 20 years. The highlight of the LHC running so far has been the discovery of the Higgs boson, but the LHC programme has also consisted of the measurement of a myriad of other Standard Model processes, as well as searches for Beyond-the-Standard-Model physics, and the discrimination between possible new physics signatures and their Standard Model backgrounds. Essentially all of the physics processes at the LHC depend on quantum chromodynamics, or QCD, in the production, or in the decay stages, or in both. This book has been written as an advanced primer for physics at the LHC, providing a pedagogical guide for the calculation of QCD and Standard Model predictions, using state-of-the-art theoretical frameworks. The predictions are compared to both the legacy data from the Tevatron, as well as the data obtained thus far from the LHC, with intuitive connections between data and theory supplied where possible. The book is written at a level suitable for advanced graduate students, and thus could be used in a graduate course, but is also intended for every physicist interested in physics at the LHC.
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Straessner, Arno. Electroweak Physics at LEP and LHC. Springer, 2012.

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Wolf, Roger. Higgs Boson Discovery at the Large Hadron Collider. Springer, 2015.

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Book chapters on the topic "Large Hadron Collider (LHC) - Higgs Boson"

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Jakobs, Karl, Günter Quast, and Georg Weiglein. "Higgs-Boson Physics at the LHC." In The Large Hadron Collider, 195–258. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-15001-7_6.

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Mellado, Bruce. "Prospects of Searches for the Higgs Boson at the LHC." In Physics at the Large Hadron Collider, 75–89. New Delhi: Springer India, 2009. http://dx.doi.org/10.1007/978-81-8489-295-6_6.

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Jenni, Peter, and Tejinder S. Virdee. "The Discovery of the Higgs Boson at the LHC." In Particle Physics Reference Library, 263–309. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38207-0_6.

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AbstractIn July 2012 the ATLAS and CMS experiments announced the discovery of a Higgs boson, confirming the conjecture put forward in the 1960’s. This article briefly traces the history of the Brout-Englert-Higgs mechanism, its impact on the elucidation of the standard model, the design and construction of the ATLAS and CMS experiments, and finally the discovery of the Higgs boson. The article outlines some of the challenges faced during the construction of the Large Hadron Collider and its experiments, and their operation and performance. In particular, recent results relating to the properties and couplings of the Higgs boson will be discussed as well future prospects at the LHC.
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Guchait, Monoranjan, and D. P. Roy. "Using Tau Polarisation for Charged Higgs Boson and SUSY Searches at the LHC." In Physics at the Large Hadron Collider, 205–12. New Delhi: Springer India, 2009. http://dx.doi.org/10.1007/978-81-8489-295-6_13.

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Sarica, Ulascan. "The Phenomenology of the Higgs Boson at the LHC." In Measurements of Higgs Boson Properties in Proton-Proton Collisions at √s =7, 8 and 13 TeV at the CERN Large Hadron Collider, 41–59. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-25474-2_3.

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Sarica, Ulascan. "The Standard Model and the Higgs Boson at the LHC." In Measurements of Higgs Boson Properties in Proton-Proton Collisions at √s =7, 8 and 13 TeV at the CERN Large Hadron Collider, 1–10. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-25474-2_1.

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Sarica, Ulascan. "Analysis of the Higgs Boson Properties During Run 1 and Run 2 of the LHC." In Measurements of Higgs Boson Properties in Proton-Proton Collisions at √s =7, 8 and 13 TeV at the CERN Large Hadron Collider, 61–92. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-25474-2_4.

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Rindani, Saurabh D. "Strong Gauge Boson Scattering at the LHC." In Physics at the Large Hadron Collider, 145–55. New Delhi: Springer India, 2009. http://dx.doi.org/10.1007/978-81-8489-295-6_10.

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Tosciri, Cecilia. "The Large Hadron Collider and the ATLAS Detector." In Higgs Boson Decays into a Pair of Bottom Quarks, 35–48. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-87938-9_4.

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Wolf, Roger. "Discovery of the Higgs Boson at the Large Hadron Collider." In Springer Tracts in Modern Physics, 81–150. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-18512-5_4.

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Conference papers on the topic "Large Hadron Collider (LHC) - Higgs Boson"

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Donato, Silvio. "Higgs boson results from the LHC Run-1." In Fourth Annual Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.276.0010.

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Galler, Peter, Werner Bernreuther, Clemens Mellein, Zong-Guo Si, and Peter Uwer. "Heavy Higgs boson resonances and their decay into top quarks at the LHC." In Fourth Annual Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.276.0088.

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Bandyopadhyay, Priyotosh. "Charged Higgs bosons in the extended supersymmetric scenario at the LHC." In Fourth Annual Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.276.0080.

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Tao, Junquan. "Searches for additional Higgs bosons at the LHC." In The Ninth Annual Conference on Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2021. http://dx.doi.org/10.22323/1.397.0077.

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Stefaniak, Tim. "Novel signatures of additional Higgs bosons at the LHC." In The Eighth Annual Conference on Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2020. http://dx.doi.org/10.22323/1.382.0006.

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Stefaniak, Tim. "Novel signatures of additional Higgs bosons at the LHC." In The Eighth Annual Conference on Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2020. http://dx.doi.org/10.22323/1.382.0006.

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Cheng, Alkaid. "Projected sensitivity of Higgs boson pair production combining the bbyy and bbtautau decay channels at the HL-LHC with the ATLAS detector." In The Tenth Annual Conference on Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2023. http://dx.doi.org/10.22323/1.422.0307.

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Krieger, Peter. "SM and Higgs at HL-LHC." In Fourth Annual Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.276.0174.

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Cadamuro, Luca. "Higgs boson couplings and properties." In 7th Annual Conference on Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2019. http://dx.doi.org/10.22323/1.350.0101.

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Chang, Ngee-Pong. "Physics of Higgs Boson Family." In Conference on New Physics at the Large Hadron Collider. WORLD SCIENTIFIC, 2016. http://dx.doi.org/10.1142/9789813145504_0016.

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