scholarly journals Was the Higgs Boson Discovered?

2015 ◽  
Vol 25 (1) ◽  
pp. 1 ◽  
Author(s):  
Nguyen Anh Ky ◽  
Nguyen Thi Hong Van
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Particle Physics ◽  
Science And Technology ◽  
General Purpose ◽  
Higgs Mechanism ◽  
Particle Accelerator ◽  
Scalar Boson ◽  
The Standard Model ◽  
Experimental Background

The standard model has postulated the existence of a scalar boson, named the Higgs boson (or the Brout-Englert-Higgs boson, for more complete). This boson plays a central role in a symmetry breaking scheme called the Higgs mechanism making the standard model realistic. However, until recently at least, the 50-year-long-sought Higgs boson had remained the only particle in the standard model not yet discovered experimentally. It is the last but very important missing ingredient of the standard model. Therefore, searching for the Higgs boson is a crucial task and an important mission of particle physics. For this purpose, many theoretical works have been done and dierent experiments have been organized. It may be said in particular that to search for the Higgs boson has been one of the ultimatums of building and running the LHC, the world's largest and most powerful particle accelerator, at CERN, which is a great combination of science and technology. Recently, in the summer of 2012, ATLAS and CMS, the two biggest and general- purpose LHC collaborations, announced the discovery of a new boson with a mass around 125 GeV. Since then, for over two years, ATLAS, CMS and other collaborations have carried out intensive investigations on the newly discovered boson to conrm that this new boson is really the Higgs boson (of the standard model). It is a triumph of science and technology and international cooperation. Here, we will review the main results of these investigations after presenting a brief introduction to the Higgs boson between the theoretical framework of the standard model and Higgs mechanism as well as a theoretical and experimental background of searching for it. This paper may attract interest of not only particle physicists but also a broader audience.

scholarly journals Synthesis on Heavy Higgs from the Standard Model to 2HDM and Beyond

2020 ◽  
Vol 18 ◽  
pp. 110-142
Author(s):  
Abdeljalil Habjia
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Cross Sections ◽  
Particle Physics ◽  
Hadron Collider ◽  
Signal Strength ◽  
Beyond The Standard Model ◽  
Decay Channels ◽  
Higgs Decay ◽  
The Standard Model

In the context of particle physics, within the ATLAS and CMS experiments at large hadron collider (LHC), this work presents the discussion of the discovery of a particle compatible with the Higgs boson by the combination of several decay channels, with a mass of the order of 125.5 GeV. With increased statistics, that is the full set of data collected by the ATLAS and CMS experiments at LHC ( s1/2 = 7GeV and s1/2 = 8GeV ), the particle is also discovered individually in the channel h-->γγ with an observed significance of 5.2σ and 4.7σ, respectively. The analysis dedicated to the measurement of the mass mh and signal strength μ which is defined as the ratio of σ(pp --> h) X Br(h-->X) normalized to its Standard Model where X = WW*; ZZ*; γγ ; gg; ff. The combined results in h-->γγ channel gave the measurements: mh = 125:36 ± 0:37Gev, (μ = 1:17 ± 0:3) and the constraint on the width Γ(h) of the Higgs decay of 4.07 MeV at 95%CL. The spin study rejects the hypothesis of spin 2 at 99 %CL. The odd parity (spin parity 0- state) is excluded at more than 98%CL. Within the theoretical and experimental uncertainties accessible at the time of the analysis, all results: channels showing the excess with respect to the background-only hypothesis, measured mass and signal strength, couplings, quantum numbers (JPC), production modes, total and differential cross-sections, are compatible with the Standard Model Higgs boson at 95%CL. Although the Standard Model is one of the theories that have experienced the greatest number of successes to date, it is imperfect. The inability of this model to describe certain phenomena seems to suggest that it is only an approximation of a more general theory. Models beyond the Standard Model, such as 2HDM, MSSM or NMSSM, can compensate some of its limitations and postulate the existence of additional Higgs bosons.

The Higgs boson: A major discovery and a problem

2019 ◽  
pp. 195-208
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Higgs Boson ◽  
Particle Physics ◽  
Gauge Theories ◽  
Higgs Mechanism ◽  
Higgs Model ◽  
Fermion Mass ◽  
Simplified Models ◽  
Mass Generation ◽  
Abelian Gauge ◽  
The Standard Model

Chapter 12 describes the main steps in the construction of the electroweak component of the Standard Model of particle physics. The classical Abelian Landau–Ginzburg–Higgs mechanism is recalled, first introduced in the macroscopic description of a superconductor in a magnetic field. It is based on a combination of spontaneous symmetry breaking and gauge invariance. It can be generalized to non–Abelian gauge theories, quantized and renormalized. The recent discovery of the predicted Higgs boson has been the last confirmation of the validity of the model. Some aspects of the Higgs model and its renormalization group (RG) properties are illustrated by simplified models, a self–interacting Higgs model with the triviality issue, and the Gross–Neveu–Yukawa model with discrete chiral symmetry, which illustrates spontaneous fermion mass generation and possible RG flows.

Is the Higgs mechanism true to the equivalence principle?

2015 ◽  
Vol 24 (12) ◽  
pp. 1544009 ◽  
Author(s):  
C. S. Unnikrishnan ◽  
George T. Gillies
Keyword(s):  
Standard Model ◽  
Equivalence Principle ◽  
Particle Physics ◽  
Higgs Mechanism ◽  
Fundamental Issue ◽  
Weak Equivalence Principle ◽  
The Standard Model ◽  
Physical Mass ◽  
Gravitational Charge

In this paper, we raise and discuss the fundamental issue whether the interaction-induced inertia in the Higgs mechanism is the same as the charge of gravity or the gravitational mass. True physical mass has to fulfill the dual role of inertia and the gravitational charge, and should respect the weak equivalence principle. This is not yet addressed in the standard model that does not incorporate gravity. Hence, the Higgs scenario still requires a gravitational completion. Some relevant analogies where interaction-induced inertia is not the same as the gravitational charge are mentioned. Probing this line of thought will provide valuable clues and perhaps a remarkable answer to the place and role of gravity in the standard model of particle physics.

scholarly journals Current Issues in the Phenomenology of Particle Physics

1997 ◽  
Vol 12 (31) ◽  
pp. 5531-5554 ◽  
Author(s):  
John Ellis
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Present Status ◽  
Particle Physics ◽  
Neutrino Oscillations ◽  
Experimental Tests ◽  
Grand Unification ◽  
The Standard Model

The present status of the Standard Model and its experimental tests are reviewed, including indications on the likely mass of the Higgs boson. Also discussed are the motivations for supersymmetry and grand unification, searches for sparticles at LEP, neutrino oscillations, and the prospects for physics at the LHC.

scholarly journals The Standard Model

2012 ◽  
Vol 370 (1961) ◽  
pp. 805-817 ◽  
Author(s):  
Tara Shears
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Particle Physics ◽  
Experimental Tests ◽  
Fundamental Particles ◽  
The Standard Model ◽  
Fundamental Forces ◽  
Physics Experiments

The Standard Model is the theory used to describe the interactions between fundamental particles and fundamental forces. It is remarkably successful at predicting the outcome of particle physics experiments. However, the theory has not yet been completely verified. In particular, one of the most vital constituents, the Higgs boson, has not yet been observed. This paper describes the Standard Model, the experimental tests of the theory that have led to its acceptance and its shortcomings.

The Discovery of a Higgs Particle at the Large Hadron Collider

2015 ◽  
Vol 23 (1) ◽  
pp. 57-70
Author(s):  
Aleandro Nisati
Keyword(s):  
Higgs Boson ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Particle Physics ◽  
Hadron Collider ◽  
Scientific Programme ◽  
Fundamental Particle ◽  
The Standard Model ◽  
8 Tev ◽  
The Masses

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’.

scholarly journals The pre-LHC Higgs hunt

2015 ◽  
Vol 373 (2032) ◽  
pp. 20140039 ◽  
Author(s):  
G. Dissertori
Keyword(s):  
Higgs Boson ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Particle Physics ◽  
Hadron Collider ◽  
Precise Data ◽  
Electron Positron ◽  
The Standard Model ◽  
The World ◽  
Large Electron Positron

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.

SEARCH FOR THE STANDARD MODEL HIGGS BOSON WITH THE ATLAS DETECTOR

2013 ◽  
Vol 22 (07) ◽  
pp. 1330015
Author(s):  
◽  
DOMIZIA ORESTANO
Keyword(s):  
Higgs Boson ◽  
Large Hadron Collider ◽  
Standard Model ◽  
Particle Physics ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Standard Model Higgs Boson ◽  
Cern Large Hadron Collider ◽  
Atlas Experiment ◽  
The Standard Model

This document presents a brief overview of some of the experimental techniques employed by the ATLAS experiment at the CERN Large Hadron Collider (LHC) in the search for the Higgs boson predicted by the standard model (SM) of particle physics. The data and the statistical analyses that allowed in July 2012, only few days before this presentation at the Marcel Grossman Meeting, to firmly establish the observation of a new particle are described. The additional studies needed to check the consistency between the newly discovered particle and the Higgs boson are also discussed.

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