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.

Filter by
Sorted by
Tagged with
0
votes
2answers
71 views

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 ...
2
votes
1answer
57 views

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-$\sigma$ ...
1
vote
0answers
33 views

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?
1
vote
2answers
34 views

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 ...
1
vote
1answer
94 views

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 ...
0
votes
1answer
70 views

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 ...
0
votes
1answer
41 views

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}{...
1
vote
0answers
24 views

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&...
4
votes
1answer
95 views

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 ...
0
votes
0answers
18 views

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 ...
0
votes
1answer
32 views

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 ...
1
vote
1answer
72 views

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|^...
0
votes
0answers
13 views

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 ?
1
vote
1answer
53 views

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 ...
1
vote
1answer
39 views

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 ...
0
votes
2answers
71 views

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 ...
1
vote
1answer
41 views

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 ...
0
votes
1answer
38 views

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
0
votes
2answers
82 views

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.
0
votes
0answers
21 views

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 ...
1
vote
1answer
67 views

$SU(2) \to I$ 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 ...
2
votes
1answer
32 views

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 ...
0
votes
1answer
34 views

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 $\mu$ ...
0
votes
0answers
43 views

How does the unitary gauge make Goldstone modes disappear?

I know that, in the Glashow-Weinberg-Salam model of electroweak theory, small oscillations of the Higgs field about the minimum \begin{equation} \phi_0= \begin{pmatrix} 0\\ a \end{pmatrix} \end{...
1
vote
1answer
81 views

Where does the Goldstone couplings go in the unitary gauge?

Imagine that you have some model with an enlarged scalar potential, such that there is, for instance, a quartic coupling $\kappa$ between the Higgs charged component and three other scalars, which do ...
0
votes
2answers
55 views

What defines the strength of a Higgs Field?

How can the strength of a Higgs Boson Field be measured?It is a scalar field and doesn't have a source unlike other fields such as gravity.What would the units be for a strength of the field at a ...
0
votes
2answers
84 views

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 ...
-3
votes
2answers
142 views

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" ...
3
votes
2answers
100 views

Can Higgs potential provide a cosmological constant?

Usually, in particle physics, people do not care about a constant term in scalar field potential. Rather, attentions are paid to the local profile at the minimum. But in the context of cosmology, the ...
0
votes
0answers
46 views

Does Supersymmetry really assures that the Higgs self-energy contributions cancel out?

The well-known "Supersymmetry Primer" from Stephen Martin explains in his introduction that for the cancellation of the Higgs self-energy diagrams (Fig. 1.1 a + b) generated by fermions and their ...
0
votes
0answers
38 views

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 ...
1
vote
2answers
64 views

Can a GUT be spontaneously broken mutiple ways?

Say we have a GUT e.g. $SU(5)$, if the Higgs field breaks this it can break it down to $SU(3)\times SU(2)\times U(1)$ if the Higgs field acquires values proportional to the weak hypercharge. But can ...
-4
votes
1answer
69 views

Objects falling in a black hole [closed]

I was wondering : object approaching the event horizon of a black hole reach relative velocities ~ c ( But since the object has relative velocities of nearly c then its buildings blocks have ...
0
votes
0answers
14 views

Is there a symmetry breaking model possible for mirror fermions in $E_8$?

I've often been struck by how nicely the Standard model seems to fit into (supersymmetric) $E_8$. Specifically if we write the root vectors of $E_8$ as $(R,G,B,W,H,F,S,T)$. With colour being the ...
2
votes
1answer
168 views

Review: If true, what makes the vacuum of a local ${\rm U(1)}$ gauge theory unique?

Long back, I posted a question with title "Is the vacuum of a local U(1) gauge theory unique?", which, as the title suggests asked whether the vacuum of a "spontaneously broken" the gauge theory is ...
1
vote
0answers
33 views

Higgs mechanism to break $E_8$ down to $SU(8)$?

Say you had the group $E_8$ and you wanted to break it down to $SU(8)$ via a Higgs symmetry breaking potential. Is this possible? (We know it is a subgroup at least since $E_8$ contains $O(16)$). For ...
1
vote
2answers
77 views

Apparent coincidence of spin-connection term and Higgs field?

In curved space time, there is a spin-connection term $\overline{\psi}\gamma^\mu\sigma^{ab}\omega^{ab}_\mu\psi$. Here's my apparent problem. If there were no Higgs field and no gravity, all particles ...
-5
votes
2answers
83 views

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 ...
1
vote
0answers
31 views

Does the order in which elements are placed in a Feynman diagram's amplitude equation matter?

When writing the maths expression for the amplitude of a Feynman diagram I started from the right to the left and ended up with something like: $$\epsilon^*(z_3) \epsilon^*(z_4) ....... \epsilon (z_2)...
1
vote
1answer
62 views

How do I calculate the amplitude of an $s$-channel Feynman diagram?

What is is the starting point to measure the amplitude in an $s$-diagram like the one below where two particles collide and create a propagator followed by the final product? I know that in $t$-...
0
votes
0answers
23 views

How am I meant to use momenta and polarisation vectors in a Feynman diagram?

I'm trying to calculate the tree-level amplitude of a diagram and I am given the momenta and the polarisation vectors. How do I use these to get to the simplest form of the amplitude. What is the ...
0
votes
0answers
41 views

What is the meaning of the structure constant for the $\rm SU(3)$ group and how I can find its values? [duplicate]

To calculate the tree-level amplitude for: $$Z(p_1) + Z(p_2) \to Z(p_3) +Z(p_4)$$ I must take into the consideration, amongst other cases, the amplitude for: I know the values shown in another post ...
0
votes
1answer
44 views

How do I find the values for the structure constants ($f^{abc}$) of a gauge group?

How do I find the values for the structure constants ($f^{abc}$) of a gauge group, as a mean to find the tree-level amplitude for a process in which one of the tree-level diagrams is: the process ...
3
votes
0answers
52 views

The Higgs mechanism in a quiver gauge model

I've been reading chapter 20 in Peskin and Schroeder about the Glashow-Weinberg-Salam Theory for a $U(1)$ gauge symmetry with gauge coupling strengths $g$, and a complex scalar $\phi$, specifically ...
14
votes
3answers
992 views

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, ...
0
votes
0answers
42 views

Higgs vev: diagonal or not?

I've read at different, places (for instance, this answer) that you can choose the vev of an adjoint Higgs to correspond to a generator of the Cartan subalgebra of the symmetry you are trying to break....
2
votes
2answers
99 views

Symmetry breaking and higgs representation

I was wondering if there is a criterion for the representation the Higgs should change under or if it's a case by case scenario. For instance, electroweak symmetry breaking is done with a higgs in ...
0
votes
1answer
52 views

Photons, Gravity and Higgs field [closed]

(a) A photon's path bends towards a large mass, so we say it has gravitational attraction (or that the large mass bends spacetime so that the photon's path curves towards it). But if the photon feels ...
0
votes
0answers
57 views

Energies needed for massive particles to reach light speed, such as W/Z bosons at electroweak energy levels - limitation of special relativity?

I have learned that before 10^-32 s after the big bang, when the universe was at 10^15 degrees Kelvin, particles that carry the weak nuclear force, the W and Z bosons (which have mass), no longer ...
0
votes
0answers
38 views

What is the energy of the vaccuum : is it the average of $<\phi_H>$, or the value of the potential?

If we consider Higgs boson theory, the Higgs potential which is introduced is a mexican hat potential. Before electroweak symmetry breaking, the field is exactly 0, and the potential is non null. ...

1
2 3 4 5
17