This higgs field breaks electroweak symmetry and provides mass to particles though a process called the higgs mechanism. The excitation of the higgs field is called a higgs boson.

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Electroweak phase transition

Is it true that when the temperature of the universe was greater than ~200GeV the Higgs did not have any nonzero vacuum expectation value, hence all the particles were massless? So if one calculates ...
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20 views

Enhanced D-Brane Gauge Symmetry and the string decoupling limit

Consider a system of $N_C$ $Dp$-branes (in Type IIA or Type IIB string theory, depending on whether $p$ is even or odd). In the Les Houches lectures on supersymmetric gauge theories by Berman and ...
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Do the broken symmetry functions of a Mexican hat potential form a smooth function throughout space?

When the symmetry of a Mexican hat potential is spontaneously broken, the new zero potential comes to lie on one of the points on the rim of the hat (the collections of potentials with zero as value). ...
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49 views

Understanding standard model and symmetry

I just want to know whether my understanding regarding standard model and symmetry is correct or utter nonsense. The standard model is the (yet incomplete) Lagrangian of the universe. The ...
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53 views

The group SU(2) and the Higgs field

The Higgs field matrix has the structure $\Phi=\begin{bmatrix} \phi_{+} & -\phi_{0}^{*} \\ \phi_{0} & \phi_{+}^{*} \\ \end{bmatrix}$ How can I show that it keeps this structure under the ...
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1answer
30 views

How do quarks interact with the higgs field

I know that electrons' only interaction with the higgs field is due to ambidextrousness and the weak hypercharge which is provided by the higgs boson, but how do quarks (specifically up and down) ...
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51 views

Virtual Photons [duplicate]

In QFT formalism of Feynman diagrams, all propagators must be off-shell otherwise they would end up being undefined. The latter implies that physically we might regard these force messengers (i.e. ...
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0answers
11 views

Why is the bottom antibottom decay channel for the Higgs difficult to observe? [duplicate]

This is a question from a past paper on particle physics, it asks: Explain why experimentally it was easier to observe $h \to\gamma\gamma$ rather than $h \to b\bar b$ which has the highest ...
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1answer
79 views

Perturbativity of SM Higgs quartic coupling [closed]

I'm little confused about the maximal appropriate value for the SM Higgs quartic coupling. I know that the Higgs mass, $m_h= 125 \,\text{GeV}$ and that $ \lambda = m_h^2 / 2 v^2 \simeq 0.1 $ for $v = ...
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What's new with the Higgs boson?

sorry for the "What's" in the question (but I couldn't figure out something more accurate to my doubt (I am not a physicist)). I have a question of legitimate curiosity, what are the last findings ...
2
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0answers
38 views

Massless excitations without SSB

Is there possible the situation when there are massless excitations in spectrum of states in a theory with phase transition but without spontaneous symmetry breaking? The motivation for this question ...
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2answers
73 views

Why do particle physicists use the $h\rightarrow{\gamma\gamma}$ decay mode rather than $h\rightarrow{b\bar{b}}$?

Just wondering, the $h\rightarrow{\gamma\gamma}$ decay mode is often quoted as being most sensitive to measuring the mass of the Higgs particle, why isn't the $h\rightarrow{b\bar{b}}$ decay channel ...
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27 views

Symmetry breaking with adjoint matter, departing from vacuum in different way

$$L=-\frac{1}{4}TrF_{\mu\nu}F^{\mu\nu}+\frac{1}{2}D_\mu\phi D^\mu \phi -\lambda V(\phi)$$ Say we have a potential $V(\phi)=(|\phi|^2-v^2)^2$, and 3-component real scalar field $\phi=(\phi_1, \phi_2, ...
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1answer
40 views

Why is $\sqrt{v_1+v_2+\ldots} =246$ GeV in multi-Higgs models?

Where does the condition come from that in models with several electroweak breaking doublets the square root of the squared sum of the VEVs should yield $246$ GeV?
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1answer
50 views

Can a symmetry breaking VEV lie far above the “symmetry breaking scale?”

The scale where some symmetry gets broken can be computed using the renormalization group equations for the gauge couplings. If there is only one Higgs VEV responsible for some breaking, can this VEV ...
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23 views

What are the Higgs masses for $SU(2) \times U(1)$ goes to $U(1)$ symmetry breaking with a complex triplet?

Consider an $SU(2)\times U(1)_Y\rightarrow U(1)_{EM}$ theory that is broken via a complex triplet with hypercharge 2. The potential is of the form \begin{align} V(\Phi) = -m^2\Phi^\dagger\Phi + ...
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2answers
127 views

Why do people say that the Higgs mechanism gives mass to the gauge bosons without mentioning the fermions?

Many presentations of the Higgs mechanism only explain it as giving mass to the $W$ and $Z$ gauge bosons, but don't mention the quarks or charged leptons. For example: ...
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15 views

Decay kinematics of Higgs boson

So I'm looking at a two-body decay question for the $h\rightarrow\gamma\gamma$ decay channel for the Higgs Boson. I am asked to find the invariant mass of the Higgs boson. I'm not too sure how to ...
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how to construct a model with fully broken SU(2) gauge symmetry, in which the masses of all three vector bosons are different

When we do the spontaneous symmetry breaking of SU(2) local gauge symmetry, the three vector fields acquire mass which is equal for all three of them. Now how do I construct a model in which the ...
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1answer
37 views

Why do the different lepton generations have different masses?

I've been reading Mark Srednicki's book on Quantum Field Theory, and toward the end (Chapter 88), he describes how the different generations of leptons acquire mass via Yukawa interactions. However, ...
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24 views

What is the difference between the generation of mass for Fermions compared with Bosons in the standard model?

I've seen a few questions asking how the Higgs mechanism generates mass for particles of the standard model. However, I haven't seen any which specify the differences between Bosons and Fermions in ...
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How is the ground state chosen in a spontaneous symmetry breaking process?

This question is about how the ground state is chosen in a spontaneous symmetry breaking process. Say we have a Mexican Hat potential (e.g. the one for the Higgs field) and are sitting at the unstable ...
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1answer
97 views

Does massive particle really move at speed of light? [closed]

According to this answer I understood that particles with mass also move at speed of light but interaction with higgs field make this movement zigzag. So average speed is below speed of light. But I ...
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1answer
189 views

How can the Higgs boson explain the inertia of the body?

We consider a thought experiment. Let weightless cylinder is located in the reference frame $K'$ (axis X, Y, Z). The height of the cylinder is equal to $h$ (Fig.1). The top cover of the cylinder is ...
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Why did it take so long to find the Higgs?

The $W$ and $Z$ boson took a long time to be discovered because they were so heavy; we couldn't produce them in a particle collider until the 80's. But the Higgs boson isn't that much heavier than the ...
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Running coupling, effective potential and the stability of vacuum

Consider the potential $$V(\phi)=\frac{1}{2}\mu^2\phi^2+\lambda\phi^4$$ where $\phi=\phi(t,\textbf{x})$ is a real scalar field. Let, $\mu^2<0$ and $\lambda>0$ then the potential is bounded from ...
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2answers
120 views

Higgs boson and dark matter.

In the standard model the Higgs boson gives the mass to other particles, but in the Universe we know that the 80% of mass is in form of dark matter, that is not constituted by known particles. The ...
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37 views

Why do Higgs decays depend on the production method?

I'm reading about Higgs phenomenology and I have come across the following table. I don't see why gluon fusion to $b \bar{b}$ is considered to be "impossible" in this table. As far as I can tell, ...
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Higgs mechanism on a brane- application to a 2d superconductor

In usual three-dimensional superconductors the would-be Goldstone mode is eaten up by the electromagnetic gauge field via the standard Higgs mechanism. I am thinking now about a problem of a ...
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1answer
87 views

How do Higgs field provide mass to other particles? [closed]

I know this question has been posted so many times here but still I have some confusions about Higgs mechanism. I watched some videos relating to Higgs mechanism and they says the Higgs field provide ...
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If it was to turn out that there are five different Higgs Fields how would each interact differently with other particles?

I have read before that there may be five different types of Higgs Fields. If this was to turn out to be the case then which Higgs Fields would give which particles mass?
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Can we in the far future have an energy source made from vacuum energy, antimatter, dark energy, Higgs boson? [closed]

Can we in the far future have an energy source made from vacuum energy, antimatter, dark energy, Higgs boson and all kind of these like stuffs?
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How do we know that A is a pseudoscalar (CP-odd) Higgs?

Starting from a model with two complex Higgs doublets (as e.g. in the MSSM) we arrive at 5 physical Higgs bosons (instead of 1 as in the Standard Model), 2 of which are charged and 3 are neutral. One ...
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2answers
115 views

Origin of Mexican hat potential in Higgs mechanism

I have recently read a layman's version of the Higgs mechanism with a Mexican hat potential. The only thing I don't get is what actually causes the Higgs potential to have a Mexican hat shape?
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1answer
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Restoration of spontaneously broken symmetry at high energy

It is common to find books saying that above a certain energy, a certain symmetry in particle physics is restored, e.g. the $SU(2)\times U(1)$ electroweak symmetry was unbroken between $10^{-36}$ to ...
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35 views

A question relating to the Higgs boson scalar field

Just wondering. The potential for the Higgs boson is given by: $$ V(\varphi)=\lambda(\varphi^{2}-v^{2})^{2} $$ where $v≃$ 246 GeV is the vacuum expectation value required to explain mass in the ...
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1answer
25 views

How to calculate the decay rate of Higgs to lepton pair?

In class, the generic formula we've been given for calculating scattering amplitudes for the weak decay (at low energies so that the interaction is effectively point-like) is $$ M= ...
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2answers
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Chiral symmetry breaking and confusion with terminology

I am confused about Chiral symmetry breaking and the terminology we use. First of all, I think the symmetry is started with taking quark masses zero and writing the Lagrangian as; $$ ...
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3answers
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Why do we need to “create our own” Higgs boson in order to see one?

I understand that the LHC found the Higgs boson by pumping so much energy into a tiny space (via near light speed proton-proton collisions) that a Higgs boson appeared momentarily, then instantly ...
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1answer
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Is there any Higgs Model that has 4 Charged Higgs and 1 Neutral?

There is a 2HDM that predicts 3 neutral and 2 charged Higgs particles. There are also many more models out there. I already did some searching, but there is a large body of work here, and various ...
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1answer
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why does the higgs mechanism need to exist?

I feel like this is kind of a pleb question but I'm gonna ask it anyway. As far as I know, mass is fundamentally the property that a field has when it can have energy without having momentum. But why ...
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1answer
64 views

Why do some fields have a distance limit and other don't? [closed]

I'm not a mathematician or a physicist but interested in quantum mechanics/gravity/relativity. I'm trying to understand some ideas that are presented for laymen, and a lot of them talk about different ...
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1answer
95 views

Reason for not using Higgs mechanism to solve mass gap problem

I am curious as to precisely why one can't introduce masses for gluons in Yang-Mills by a Higgs-type mechanism as in electroweak theory. Is it because then one would end up with an unwanted massless ...
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1answer
55 views

Correct Yukawa Term with a SU(2) Higgs Triplet?

Given $SU(2)$ doublet fermions $\Psi^1$ and $\Psi^2$ and a $SU(2)$ triplet Higgs $H$, how does the correct Yukawa term look like in tensor notation? Schematically, we have $$ 2 \otimes 2 \otimes 3 ...
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1answer
32 views

Does having inertial mass demand that the particle must have (Higgs and other) potential energy?

My understanding is that a photon is pure kinetic energy and has no inertial mass of its own (or probably too low to be significant). But for a box with two photons whose momentums cancel, the photons ...
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Feynman rules complex field in polar form

I am trying to derive the Feynman rules for this field: $$L=-\partial \phi^*\partial \phi - \frac{\lambda}4 (|\phi|^2-v^2)^2 $$ With this coordinates $\phi = \frac 1 {\sqrt2}\rho \exp(i \theta)$, ...
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Feynman diagrams with ghosts and symmetry breaking

Let us think of an abelian gauge theory, precisely a scalar QED with 3 complex components of the scalar field and a 4-degree auto-interaction mixing components. Let us consider a spontaneously ...
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79 views

$\rho$-parameters for several Higgs multiplets

I'm studying the Higgs mechanism of the spontaneus symmetry breaking in the SM. The expression for the $\rho$-parameter is $$ \rho=\frac{M^2_W}{{\cos^2\theta_w}M^2_Z}, $$ that, in the case of a ...
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31 views

Why does Higgs break the symmetry

Usually classical analogies are given of the form: A ball sits on top of a mexican hat potential, rolls down spontaneously and will come to rest at at minimum. But classical systems of balls on hills ...