The Higgs mechanism from the effective theory of the non-minimal gravity action (original) (raw)
Related papers
Does the Higgs Mechanism Exist?
International Studies in the Philosophy of Science, 2008
This paper explores the argument structure of the concept of spontaneous symmetry breaking in the electroweak gauge theory of the Standard Model: the so-called Higgs mechanism. As commonly understood, the Higgs argument is designed to introduce the masses of the gauge bosons by a spontaneous breaking of the gauge symmetry of an additional field, the Higgs field. The technical derivation of the Higgs mechanism, however, consists in a mere re-shuffling of degrees of freedom by transforming the Higgs Lagrangian in a gauge-invariant manner. This already raises serious doubts about the adequacy of the entire manoeuvre. It will be shown that no straightforward ontic interpretation of the Higgs mechanism is tenable since gauge transformations possess no real instantiations. In addition, the explanatory value of the Higgs argument will be critically examined.
Higgs-less Higgs mechanism: low-energy expansion
In this talk, we describe an effective theory for electroweak symmetry breaking without a physical Higgs, based on a symmetry larger than the electroweak gauge group. This symmetry forbids deviations from the Standard Model at the leading order in the appropriate chiral expansion. Indeed, the large symmetry allows for a consistent expansion of the effective theory in powers of momenta and spurions. The latter are automatically present: they define the covariant reduction from the large symmetry to the electroweak group.
Spontaneous Breaking of Global Gauge Symmetries in the Higgs Mechanism
Spontaneous Breaking of Global Gauge Symmetries in the Higgs Mechanism, 2024
The Higgs mechanism is invoked to explain how gauge bosons can be massive while Yang-Mills theory describes only massless gauge fields. Central to it is the notion of spontaneous symmetry breaking (SSB), applied to the SU(2) × U(1) gauge symmetry of the electroweak theory. However, over the past two decades, philosophers of physics have challenged the standard narrative of the Higgs mechanism as an instance of gauge symmetry breaking. They have pointed out the apparent contradiction between the status of gauge symmetries as mathematical redundancies and the account of mass generation in the Higgs mechanism by means of gauge symmetry breaking. In addition, they have pointed to Elitzur's theorem, a result from lattice gauge theory forbidding local gauge symmetry breaking. This has led philosophers to the conclusion that there cannot be any SSB in the Higgs mechanism, an idea supported by the dressing field method of gauge symmetry reduction. In this thesis we mitigate this conclusion by showing that global gauge symmetries, i.e. transformations independent of spacetime, are not mere mathematical redundancies but carry direct empirical significance. This can be seen from constrained Hamiltonian analysis by the fact that the Gauss constraint in Yang-Mills theory only generates gauge transformations which asymptotically become the identity. The classical Higgs mechanism can indeed be reformulated as a breaking of only this global gauge symmetry. We subsequently extend this result to quantum field theory by considering SSB in algebraic quantum field theory (AQFT). The Abelian U(1) Higgs mechanism can be shown to be an instance of SSB in the algebraic sense and we discuss the extent to which this can be generalised to the non-Abelian case. Finally we discuss the implications of our results for the interpretation of the electroweak phase transition and the analogy between the Higgs mechanism and superconductivity.
The Higgs mechanism is an essential but elusive component of the Standard Model of particle physics. Without it Yang-Mills gauge theories would have been little more than a warm-up exercise in the attempt to quantize gravity rather than serving as the basis for the Standard Model. This article focuses on two problems related to the Higgs mechanism clearly posed in Earman’s recent papers (Earman 2003, 2004a, 2004b): what is the gauge-invariant content of the Higgs mechanism, and what does it mean to break a local gauge symmetry?
Higgsless theory of electroweak symmetry breaking from warped space
Journal of High Energy Physics, 2003
We study a theory of electroweak symmetry breaking without a Higgs boson, recently suggested by Csaki et al. The theory is formulated in 5D warped space with the gauge bosons and matter fields propagating in the bulk. In the 4D dual picture, the theory appears as the standard model without a Higgs field, but with an extra gauge group G which becomes strong at the TeV scale. The strong dynamics of G breaks the electroweak symmetry, giving the masses for the W and Z bosons and the quarks and leptons. We study corrections in 5D which are logarithmically enhanced by the large mass ratio between the Planck and weak scales, and show that they do not destroy the structure of the electroweak gauge sector at the leading order. We introduce a new parameter, the ratio between the two bulk gauge couplings, into the theory and find that it allows us to control the scale of new physics. We also present a potentially realistic theory accommodating quarks and leptons and discuss its implications, including the violation of universality in the W and Z boson couplings to matter and the spectrum of the Kaluza-Klein excitations of the gauge bosons. The theory reproduces many successful features of the standard model, although some cancellations may still be needed to satisfy constraints from the precision electroweak data.
Jacob Bekenstein, 2019
Motivated by the ideas of Jacob Bekenstein concerning gravity-assisted symmetry breaking, we consider a non-canonical model of f (R) = R + R 2 extended gravity coupled to neutral scalar "inflaton", as well as to SU (2) × U (1) multiplet of fields matching the content of the bosonic sector of the electroweak particle model, however with the following significant difference-the SU (2) × U (1) iso-doublet Higgs-like scalar enters here with a standard positive mass squared and without quartic selfinteraction. Strong interaction dynamics and, in particular, QCDlike confinement effects are also considered by introducing an additional coupling to a strongly nonlinear gauge field whose Lagrangian contains a square-root of the standard Maxwell/Yang-Mills kinetic term. The latter is known to produce charge confinement in flat spacetime. The principal new ingredient in the present approach is employing the formalism of non-Riemannian spacetime volume-forms-alternative generally covariant volume elements independent of the spacetime metric, constructed in terms of auxiliary antisymmetric tensor gauge fields of maximal rank. Although being almost pure-gauge, i.e. not introducing any additional propagating degrees of freedom, their dynamics triggers a series of physically important features when passing to the Einstein frame: (i) Appearance of two infinitely large flat regions of the effective "inflaton" scalar potential with vastly different energy scales corresponding to the "early" and "late" epochs of the Universe; (ii) Dynamical generation of Higgs-like spontaneous symmetry breaking effective potential for the SU (2) × U (1) iso-doublet scalar in the "late" Universe, and vanishing of the symmetry breaking in the "early" Universe; (iii) Dynamical appearance of charge confinement via the "square-root" nonlinear gauge field in the "late" Universe and deconfinement in the "early" Universe.
Gravity-Assisted Emergent Higgs Mechanism in the Post-Inflationary Epoch
2016
We consider a non-standard model of gravity coupled to a neutral scalar "inflaton" as well as to SU(2)xU(1) iso-doublet scalar with positive mass squared and without self-interaction, and to SU(2)xU(1) gauge fields. The principal new ingredient is employing two alternative non-Riemannian space-time volume-forms (covariant integration measure densitities) independent of the metric. The latter have a remarkable impact - although not introducing any additional propagating degrees of freedom, their dynamics triggers a series of important features: appearance of infinitely large flat regions of the effective "inflaton" potential as well as dynamical generation of Higgs-like spontaneous symmetry breaking effective potential for the SU(2)xU(1) iso-doublet scalar.
Towards a Realistic Model of Higgsless Electroweak Symmetry Breaking
Physical Review Letters, 2004
We present a 5D gauge theory in warped space based on a bulk SU (2) L × SU (2) R × U (1) B−L gauge group where the gauge symmetry is broken by boundary conditions. The symmetry breaking pattern and the mass spectrum resembles that in the standard model (SM). To leading order in the warp factor the ρ parameter and the coupling of the Z (or equivalently the S-parameter) are as in the SM, while corrections are expected at the level of a percent. From the AdS/CFT point of view the model presented here can be viewed as the AdS dual of a (walking) technicolor-like theory, in the sense that it is the presence of the IR brane itself that breaks electroweak symmetry, and not a localized Higgs on the IR brane (which should be interpreted as a composite Higgs model). This model predicts the lightest W , Z and γ resonances to be at around 1.2 TeV, and no fundamental (or composite) Higgs particles. * Other interesting possibilities for EWSB using extra dimensions is to have the Higgs be the extra dimensional component of a gauge field, see for example , or to have a warped compactification where the would-be zero mode for the gauge field is not normalizable .
'The Higgs Mechanism' --- Senior Honours Group Project
We will describe the Higgs mechanism, a theory accounting for the mass of fundamental particles which make up the baryonic matter in our universe. The mathematical methods needed to investigate the nature of the coupling between the Higgs field and soon-to-be massive gauge field will be discussed, and we will explore how a mass term arises.
Gauge invariant accounts of the Higgs mechanism
2011
The Higgs mechanism gives mass to Yang-Mills gauge bosons. According to the conventional wisdom, this happens through the spontaneous breaking of gauge symmetry. Yet, gauge symmetries merely reflect a redundancy in the state description and therefore the spontaneous breaking can not be an essential ingredient. Indeed, as already shown by Higgs and Kibble, the mechanism can be explained in terms of gauge invariant variables, without invoking spontaneous symmetry breaking. In this paper, we present a general discussion of such gauge invariant treatments for the case of the Abelian Higgs model, in the context of classical field theory. We thereby distinguish between two different notions of gauge: one that takes all local transformations to be gauge and one that relates gauge to a failure of determinism.