Electroweak symmetry breaking and new physics at the tev. Pdf in this chapter, we summarize the structure of the standard ew theory. This is a question that i have tried to pose several times without any success but, anyway, i would like to try again for the very last time. Spontaneous symmetry breaking in strong and electroweak. The higgs boson is the dangling thread that could unravel the standard model, at last revealing what lies beyond it. An effective lagrangian, valid when there is no low mass higgs boson, is used to discuss the physics of a strongly interacting electroweak symmetry breaking sector.
Electroweak precision testfermion sectorphenomenology conclusions more on emergent gauge theory emergent gauge symmetry breaking or composite gauge boson isconceptually innocuous, even inspiring. Aspects of electroweak symmetry breaking in physics beyond the. Higgs boson, is used to discuss the physics of a strongly interacting electroweak symmetry breaking. In the standard model of particle physics, elementary particles acquire mass through the process of electroweak symmetry breaking. To accommodate all observed phenomena, a complex isodoublet scalar. Signals could be observed with an integrated luminosity of 30 fb1. The higgs boson and electroweak symmetry breaking 1. The higgs boson was named after peter higgs, a scottish theorist who, in the early 1960s, was among the first to find it hiding in the equations that would become the. What happens to the weak interaction after electroweak symmetry breaking. Gauge symmetry, unlike global symmetry, is not a true symmetry of nature, does not lead to new conserved charge. Pdf the theory of electroweak interactions researchgate. The phenomenon of dynamical symmetry breaking dsb in quantum field theory is discussed in a detailed and comprehensive way. Trefil invokes some analogies in the realm of classical physics.
Outline 1 introduction 2 symmetry and conservation law 3 explicit vs spontaneous symmetry breaking 4 goldstone theorem 5 spontaneous symmetry breaking in global symmetry 6 spontaneous symmetry breaking in local symmetry higgs phenomena 7 standard model of electroweak interaction lingfong li carnegie mellon university introduction to spontaneous symmetry. The thesis is a collection of works on diverse topics, ranging from dynamical electroweak symmetry breaking to color superconductivity of dense quark matter and goldstone boson counting in dense relativistic systems. In this note i will discuss the gauge bosons and their couplings. Spontaneous symmetry breaking in the higgs mechanism. We find that the current uncertainty in the triple and. Strong dynamics and electroweak symmetry breaking arxiv. Subsequently, i discuss the symmetry breaking sector in supersymmetric models and then consider models of dynamical electroweak symmetry breaking. Electroweak spontaneous symmetry breaking physics forums. Electroweak symmetry breaking without a higgs boson. In this talk, i recall the history of the development of the unified electroweak theory, incorporating the symmetry breaking higgs mechanism, as i saw it from my standpoint as a member of abdus. Volume 21 friday, january 23, 1998 number 2 what is. Spontaneous symmetry breaking in the electroweak model. Electroweak symmetry breaking, higgs and technicolor.
Although electroweak symmetry breaking is essential to the proven success of the standard model, the. Standard model sm of particle physics, the electroweak symmetry breaking ewsb provides a way to generate gauge boson masses through the celebrated higgs mechanism. When i was a student, i was told that the goal of elementary particle physics was to learn the basic laws of the strong and weak interactions. The higgs mechanism as well as technicolor models of dynamical symmetry breaking are described and their advantages and shortcomings. Asume for a moment that ewssb electroweak spontaneous symmetry breaking actually happened in our early universe.
Pdf electroweak symmetry breaking and precision data. The higgs boson breaks electroweak symmetry spontaneously. Electroweak symmetry breaking and new physics at the tev scale. Theoretical developments over the past decade have led to viable models and mechanisms that are consistent with current experimental data. Implications of the higgs boson discovery emconsulte. In order to extend the standard model to tev scale energies one must address two basic questions. The breaking of electroweak symmetry, and origin of the associated weak scale, vweak. Electroweak symmetry breaking l quantum field theory. The breaking of symmetry triggers the higgs mechanism, causing the bosons it interacts with to have mass. As higgs gets heavy, electroweak predictions get further and further from data heavy higgs gives too large value of s, too small value for t ew precision measurements are a problem in higgsless models. Electroweak symmetry breaking in the light of lhc defended october 5th, 2012 in front of the following examining committee. To an outside observer unaware of the fluctuations or noise, the choice will appear arbitrary. This process is called symmetry breaking, because such. Pdf dynamical electroweak symmetry breaking francesco.
Electroweak symmetry breaking, flavour physics and bsm. New milestone reached in the study of electroweak symmetry. The electroweak symmetry breaking model of glashowsalamweinberg is presented in a pedagogic manner by leading up to it with the simpler to understand symmetry breaking models of goldstone and higgs. The core idea here is that the fundamental equation governing the electroweak force is a theory coupling three su2 bosons with matter. Electroweak symmetry breaking, higgs, beyond the standard model, compositeness, vacuum. A wholeness overview chart summarizing and comparing all three models is included, as well as a separate wholeness chart for each particular model.
We present two studies into strong symmetry breaking scenarios at the lhc. Electroweak symmetry breaking without a higgs boson elizabeth h. The deep connection between this phenomenon in condensed matter physics and particle physics is emphasized. This is an expanded version of the report by the electroweak symmetry breaking and beyond the standard model working group which was contributed to particle physics perspectives and opportunities, a report of the division of particles and fields committee for long term planning. A simple mechanism for the breaking of the electroweak symmetry is incorporated in the standard model sm 5. We find that this naturally leads to a deviation from the conventional picture of topyukawa driven electroweak symmetry breaking electroweak symmetry breaking. Pdf strong dynamics and electroweak symmetry breaking. Pdf electroweak symmetry breaking and cold dark matter. The concept of spontaneous symmetry breaking is important to the understanding of electroweak unification and further unifications. Both the hydrogen and oxygen molecules are quite symmetric when they are isolated. The realizations of dsb in such realistic theories as quantum chromodynamics and electroweak theory are considered. History of electroweak symmetry breaking article pdf available in journal of physics conference series 6261 february 2015 with 128 reads how we measure reads. Dawson physics department, brookhaven national laboratory, upton, ny 11973 an introduction to the physics of electroweak symmetry breaking is given. This is a gauge theory, and without saying so, we just told you all about it in sections 2.
Electroweak symmetry breaking in supersymmetric gauge. We discuss the realization of spontaneous symmetry breaking and the higgs. Electroweak symmetry breaking and cold dark matter from hidden sector technicolor article pdf available in international journal of modern physics a 2321 february 2008 with 26 reads. While quantum field theories constructed from gauge fields and fermions only are natural, those containing elementary scalar fields are not. The statement that wed like to understand is the following. Indirect limits on the higgs boson mass from triviality arguments, vacuum stability, and precision electroweak measurements are presented. Approximately one picosecond after the big bang, the universe cooled down enough to pass through the electroweak phase transition.
The breaking of electroweak symmetry, and origin of the associated weak scale, vweak 1 q 2 v 2gf 175 gev, may be due to a new strong interaction. Finally, the higgs bosons of the minimal supersymmetric model are considered, along with the resulting differences in phenomenology from the standard model. Dynamical symmetry breaking in quantum field theories. Therefore one needs an additional susy breaking other than those from the radion and 4d sugra multiplets.
What are the generators of the electroweak interaction after symmetry breaking. An introduction to the physics of electroweak symmetry breaking is given. One of the working groups primary goals was to study the phenomenology of. Strong electroweak symmetry breaking technicolor, topcolor. The physics of electroweak symmetry breaking physik master, fruhjahrssemeste r 2009 jos e santiago itp eth zuric h june 27, 2009. Today we give thanks for the lagrangian of the standard model of particle physics, after electroweak symmetry breaking, with no explicit higgs. The first case is a study into vector boson scattering at atlas. This is an expanded version of the report by the electroweak symmetry breaking and beyond the standard model working group which was contributed to. All models of new physics must be compared with these. However, the idea itself, and the technical details of the mechanism are far from understood.
But although the higgs mechanism had been applied successfully, the conceptual background is not clear. The standard model b gauge group and particle representations b the sm with one. Gauge theories b the symmetry principle b quantization of gauge theories b spontaneous symmetry breaking 2. Electroweak symmetry breaking j quantum field theory. In fact, theres a different reason why particle physicists are obsessed about finding the higgs or something like itthats called electroweak symmetry breaking. In particular, it can describe systems where the equations of motion or the lagrangian obey symmetries, but the lowestenergy vacuum solutions do not exhibit that same symmetry. What are the generators of the electroweak interaction.
Holographic theories of electroweak symmetry breaking without a. Corrections to jan 15, 2018 version, minor typos plus eqs 49 and 50 thanks to mengliang yao. At this point the higgs mechanism kicked in, the weak force became shortranged and observationally distinct from electromagnetism, particles gained mass, the electroweak era ended, and the quark era began and lasted one whole microsecond. What breaks the symmetry between the electromagnetic and weak nuclear force. An effective lagrangian, valid when there is no low mass.
We study the impact of lep2 constraints on the dimensionless coefficients of the electroweak chiral lagrangian on the precision observables using the improved renormalization group equations. Aspects of electroweak symmetry breaking in physics. Aspects of electroweak symmetry breaking in physics beyond the standard model peter athron department of physics and astronomy university of glasgow presented as a thesis for the degree of ph. In physics, symmetry breaking is a phenomenon in which infinitesimally small fluctuations acting on a system crossing a critical point decide the systems fate, by determining which branch of a bifurcation is taken. In the standard model of particle physics, elementary particles acquire their masses by interacting with the higgs field. Electroweak symmetry breaking without a higgs at the lhc. Sign in if you have an account, or apply for one below. What breaks the symmetry between the electromagnetic and.
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