Questions tagged [higgs]

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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Field configuration minimizing the Higgs potential

Why is it that the field configuration that minimizes the Higgs potential is said to be a constant one (meaning $\phi(x) = \phi_0$)? Is it a physical reasoning, which kind of makes sense, since a non ...
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Entangled Material

Recently I saw the case of creating two entangled electrons with opposite spins from the Higgs boson (which has no spin). The electron spins are always opposite to equal zero as a sum - conserving the ...
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Mass terms for scalar lagrangians?

First off, a pre-question: if I got this wrong, then probably the whole reasoning is wrong as well. Studying the lagrangian for a two-particle scalar field with a quartic interaction in the context of ...
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Why does the scalar field have the wrong sign mass term in its Lagrangian to spontaneously break?

In a class, the professor said that there are "some" reasons why the scalar field should have had wrong sign mass term in its lagrangian. What are those reasons? (In undergraduate textbook, Griffiths ...
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What is the total cross section for $H \rightarrow W^{+} W^{-}$?

I need to know the total cross section for the process $H \rightarrow W^{+}W^{-}$, but cannot find it anywhere. Decay widths for Higgs decays are mentioned in Peskin and Schroeder (page 776), but I ...
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Calculating decay rate for $H \rightarrow W^+ W^-$

I calculated an expression for a decay rate of a decay of Higgs boson into two $W$ bosons. The expression is as follows $$ \Gamma = \frac{g^2\sqrt{1-4\frac{M_W^2}{M_H^2}}}{64\pi \hbar} \frac{M_H^3}{...
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To which symmetry group is the original symmetry group of a theory broken when we add to the theory a scalar field with a VEV?

If one has a gauge theory with a specific symmetry group and we add to it a scalar field with a non-zero VEV, how do we know in general to which symmetry group will the original symmetry be ...
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How a discrete z2 symmetry removes flavour changing neutral current from Two Higgs Doublet Model?

By applying a discrete Z2 symmetry to the theory of Two Higgs Doublet Model it is ensured that fermions of one type couples to only one doublet. But how FCNC is removed by doing so? Because if all ...
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Mass and breaking in SSB

I actually have two different sub-questions, both based on the understanding of the quadratic term of the lagrangian, so the answer is probably linked. I will use the example of the linear-$\sigma$ ...
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When does a VEV induce another VEV?

If we have a theory with more than one Higgs doublet, when do the VEV of a scalar field of one of those doublets must induce a nonzero VEV on a scalar field of another of those doublets?
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What do massive photons have to do with superconductivity?

I keep reading that the idea of massive photons leads to an explanation of the Meissner effect but I fail to see how photons are involved with the repulsion of fields inside a superconductor. How ...
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Hypercharge of the Higgs field

I am puzzled by the hypercharge of the Higgs field. Under the entry "Higgs Mechanism" in Wikipedia, it is written: Its (weak hypercharge) U(1) charge is 1 However, under the entry "...
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Electric charge of the Higgs field

The Higgs field is \begin{equation} \Phi = \frac{1}{\sqrt{2}} \left( \begin{array}{cc} \phi_{1} + i\phi_{2} \\ \phi_{3} + i\phi_{4} \end{array} \right) \tag{1} \end{equation} with $\phi_{1}...
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Symmetry group describing the electroweak interaction

I have a question about the spontaneous symmetry breaking (SSB) and its effect on the group symmetries of the Standard Model. If I understand correctly, before SSB (at high temperatures/energies) the ...
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Trying to work out the CP-transformation property of the Higgs potential

The parity transformation property of a complex scalar field $\phi(x)$ is given by: $$P\phi(t,\textbf{x}) P^{-1}=\eta_P\phi(t,-\textbf{x})$$ where $\eta_P=\pm 1$. The charge conjugation property of a ...
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Why is the term $\bar{L}\phi R$ invariant under $SU(2)_L \times U(1)_Y$ where $\phi$ is the Higgs field?

In the explanation for the fermion masses, the term $$\bar{L}\phi R$$ is added to the Lagrangian where $L$ is a left-handed $SU(2)$ doublet, $\phi$ is the Higgs left-handed $SU(2)$ doublet and $R$ is ...
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Is it possible, that just as a boson of mass exist (Higgs boson) a boson of charge exists as well? [closed]

If that is the case would it be possible for those bosons to interact with other particles directly? Meaning the field associated with those bosons, interact with the field associated with other ...
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Instantons in 1+1 dimensional Abelian Higgs model

Let's consider the Abelian Higgs model in 1+1 dimensions in Euclidean space-time: $$L_E=\frac{1}{4e^2}F_{\mu\nu}F_{\mu\nu}+D_\mu\phi^\dagger D_\mu\phi+ \frac{e^2}{4}(|\phi|^2-\zeta)^2$$ where $\zeta&...
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How did Supersymmetry (incorrectly) predict the mass of the Higgs Boson?

In an article by CERN states The minimal version of supersymmetry predicts that the Higgs boson mass should be less than 120-130 GeV How was this conclusion reached? I could not find any answers on ...
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Is the mass of the $Z$ due to mixing with the photon “precursor” $B$ or to interaction with the Higgs?

I want to get something clear that I do not seem to understand. I used to read that the photon $A$ and the $Z$ boson are (different) linear combinations between the $\mathrm{W}^0$ (neutral weak boson ...
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QFT: Higgs mechanisms covariant derivative under gauge transformation

So we have a Maxwell field coupled to a complex $\Phi(x)$ (charged) scalar field with mass and self-interaction terms: $$L=-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}+D_{\mu}\Phi^*D^{\mu}\Phi-m^2\Phi^*\Phi-\...
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Electroweak scalar triplet coupled to Higgs

Suppose we add to the SM the following electroweak scalar triplet with hypercharge $Y_T=-1$ $$T=\begin{pmatrix} t^0 & t^-/\sqrt{2} \\ t^-\sqrt{2} & t^{--} \end{pmatrix}$$ where the ...
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Need help comparing the mass of predicted and experimented Higgs Boson mass

I have been researching for countless hours and I can not find any relevant information on calculated/predicted Higgs Boson mass for my physics report. I have looked into super-symmetry, breaking ...
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Two-field Symmetry Breaking unitary gauge

Let's consider the following theory: $$L= -\frac{1}{4}F_{\mu \nu}F^{\mu\nu} +{1\over 2} |D_\mu \Phi|^2 +{1\over 2}|D_\mu \chi|^2 + \lambda_1\bigl(|\Phi|^2-\frac{v_1^2}{2}\bigr) +\lambda_2\bigl(|\chi|^...
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About the decay of Higgs into 2 $Z$-bosons

I need to know if I understand this point. The factor of $HZZ$ vertex in the SM Lagrangian is half the value of the Feynman rule which appears in Diagrammatica. When I calculate the decay of Higgs ...
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Interacting Quantum Fields in Curved Spacetime

I was thinking this night that how would the fields interaction or the vacuum expectation value of Higgs field changes when spacetime is not flat? e.g., the higgs field interact with the electron ...
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Why is the Higgs boson chargeless?

Well, I know if this question was asked about another particle the answer would be that the charge of a particle in an intrinsic property and that’s that(as far as we currently know), and that might ...
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What is the remaining values of $\tan{\beta}$ of MSSM, not excluded by experimental searches?

What is the remaining values of $\tan{\beta}$ of MSSM, not excluded by experimental searches ?
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Is the analytical dependence of the theoretical Higgs potential with temperature known?

At the very beginning of the unvierse, the Higgs potential had a paraboloid shape. After the electroweak Symmetry Breaking, it took the mexican hat shape. Is the analytical dependence of Higgs ...
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Effect of linear terms on a QFT

I was told when first learning QFT that linear terms in the Lagrangian are harmless and we can essentially just ignore them. However, I've recently seen in the linear sigma model, \begin{equation} {\...
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Charge vs Mass in QFT: Photons vs Higgs-graviton “pair”

When we think about electric charge, one particle namely Photons is responsible of two important feature in particle physics: The property we call electric charge of an electron is statement about ...
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How is the higgs field excited to give a Higgs boson?

I understand that the excitation of the Higgs field itself is the Higgs boson, and not the Higgs field itself, which does fit somewhat into the little String theory I've read (The excitations of the ...
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Why do people say that neutrinos are either Dirac or Majorana fermions?

The question of whether a given particle "is" a Dirac or Majorana fermion is more subtle than is sometimes presented. For example, if we just consider the "old" Standard Model with massless neutrinos, ...
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Higgs Feynman Diagrams

We have been told to compute the amplitude of these diagrams: I am struggeling with some basic points (I've only computed QED diagrams such as Bhabha scattering). Do you use $\epsilon$ for the ...
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Why are the Higgs field and the electroweak field so closely related?

To my understanding, the Higgs field condensed at the same time as the electroweak symmetry was broken. The fields' doublet components merged, while the singlet components became the Higgs boson and ...
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Higgs boson positive parity, and zero spin

Can we predict the positive parity, and zero spin of the Higgs boson from the decay mode: 𝐻 → 𝛾𝛾
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How SUSY solves the hierarchy problem?

I am struggling to understand the argument for why the introduction of a stop in SUSY can solve the hierarchy problem. The quadratic divergence from the top loop in the higgs mass calculation gives a ...
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Computation of the Higgs particle decays in $ZZ$ and $WW$

I am looking for some relevant literature reporting the full computations of the decay rates of the Higgs particle into a couple of vector bosons, when one or both the particles in the pair are ...
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What would happen if the Higgs boson and the $Z$ boson collided?

I am thinking the $z$ boson would remain with the combined mass of both the $Z$ boson and the Higgs boson. This is because the Higgs boson is a spin-0 boson and the $Z$ boson is a spin-1 boson.
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Is it true that gauge boson mix only around after the electroweak symmetry breaking, while mathematics do not explicitely state that?

Is it true that gauge boson mix only around after the electroweak symmetry breaking, while mathematics do not explicitely state that ? Indeed, in the mathematical description of the linear ...
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Higgs Bosons and photons [duplicate]

The higgs boson is an elementary particle so how it can decays into another elementary particle; the photon? And why the photon doesn't interact with the Higgs field?
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Higgs Field and its application [duplicate]

Today I was wondering about how elementary particle gets the mass. Well, you know that's the Higgs Field and we all know a lot about it. It is well known that more a elementary particle interacts ...
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What corresponds to the radial component of the axion potential?

An axion can be understood as an oscillation of the axion field in some potential. In the Higgs mechanism, there are 4 degrees of freedom. The Higgs boson is the radial oscillation and 3 remaining ...
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Is the Higgs field responsible for gravity? [closed]

Since everything gets their mass by subatomic particles which get their mass by interaction with the Higgs field , we can write the mass-energy tensor of GR as the sum of the interactions of the ...
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$SU(2) \to I$ symmetry breaking

In "Cosmic strings and other topological defects" by A. Vilenkin and E. P. S. Shellard, section 2.1.3, they detail some examples of spontaneous symmetry breaking. In the first example, they discuss ...
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Higgs boson in LHC

Recently,the higgs bosons are discovered in LHC. My question is How did they come to know that the particle that are created are actually Higgs boson? On the basis of which properties,they ...
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What breaks the symmetry between the electromagnetic and weak nuclear force?

I know the electromagnetic force is mediated by a photon and the weak nuclear force is mediated by two massive bosons. Are there any other insights into why the masses are so different?
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Was photon *defined* according to Standard Model *before* electroweak symmetry breaking ? Or were there only $W_3$ and $B$?

Was photon defined according to Standard Model theory before electroweak symmetry breaking ? Or were there only $W_3$ and $B$ ? Indeed, in Electroweak to Electro/Weak Bosons? Aman pawar answers "no" ...
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SUSY $SU(5)$ GUT chiral adjoint repersentations

when you have a chiral superfield in the adjoint representation in your theory (i.e the Higgs $\Sigma_{24}$ in $SU(5)$), you can write it as a $5\times5$ Matrix: $(\Sigma_{24})_i^j=\Sigma^a (t^a)_i^j$ ...
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Non-quadratic terms in Higgs Lagrangian after the expansion about the minimum

Let's consider the Higgs Lagrangian \begin{equation} \mathcal{L}= -(\partial^\mu\phi+B^\mu\phi)^\dagger(\partial_\mu\phi+B_\mu\phi)-V(\phi^\dagger\phi) \end{equation} where $B^\mu$ is the $\mu$ ...

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