All Questions
31
questions
3
votes
1
answer
96
views
Are Higgs mechanism and SSB different phenomena?
In the Standard Model, the Higgs mechanism is associated with the Spontaneous Symmetry Breaking (SSB).
My understanding is that it is the Higgs field which breaks the $SU(2) \times U(1)$ symmetry at a ...
- 1,669
2
votes
0
answers
68
views
Masses of $SU(2)$ gauge bosons
I'm currently learning quantum field theory and I'm wondering one thing.The way I understood it is that in the $SU(2)$ Yang-Mills theory, all gauge bosons have the same mass due to the spontaneous ...
- 43
2
votes
1
answer
219
views
Cosmic Strings as Topological Defects (heuristics)
I have a lot of troubles to understand heuristically the principle behind Kibble's model for genesis of cosmic strings via Kibble mechanism. More precisely I not understand how to interpret following ...
- 1,395
-1
votes
1
answer
135
views
Hey there I'm a beginner in particle physics trying to "selfstudy" from online resources. I want to ask how much of what I learned is correct? [closed]
The information I have gained thus far regarding the standard model is;
fermions and how their intrinsic nature.
they have half spin, non zero mass, a charge, a weak hypercharge (for leptons), a ...
5
votes
0
answers
164
views
Intuition/Motivation behind necessity of Spontaneous Symmetry Breaking to generate massive gauge bosons
In field theory textbooks, it is shown that while any gauge invariant Lagrangian must involve massless gauge fields, to obtain massive gauge bosons, we must postulate the existence of a Higgs scalar ...
- 1,588
3
votes
1
answer
203
views
Gauge invariance at the quantum level post SSB in the case of Abelian Gauge theory
On page 690 in Peskin & Schroeder's book, the Higgs mechanism is discussed in the context of an Abelian Gauge theory. After the SSB, among the many terms that appear, there is a mass term for the ...
- 823
2
votes
1
answer
293
views
How does one define massive Higgs-ed gauge fields nonperturbatively?
The Higgs mechanism can be used to produce massive spin $1$ particles in a unitary and renormalizeable way. Showing that the gauge fields gain a mass is always done at weak coupling, where tree level ...
- 3,514
1
vote
0
answers
59
views
Spontaneous Symmetry Breaking vs Addition of 'Mass terms' by hand [duplicate]
Let consider an $SU(2)$ doublet of bosons $\Phi =(\phi_A, \phi_B)$
which is described by the Lagrangian
$$L = (\partial_{\mu}\Phi)^{\dagger}(\partial_{\mu}\Phi) +a^2 V(\Phi^{\dagger} \Phi)
-\frac{\...
- 1,395
2
votes
1
answer
808
views
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 ...
- 5,931
3
votes
1
answer
368
views
When does a VEV induce another VEV?
If we have a model 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?
- 313
1
vote
2
answers
55
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 ...
- 313
3
votes
1
answer
105
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 ...
- 31
4
votes
2
answers
598
views
Gauge fixing, Lorentz invariance and positive definite metric of Hilbert space
Updated 0n ${\bf 02.04.2020}$
$\large{\bf Context}$
In the first $3$ minutes of this video lecture (based on the presentation here) on the subject matter of Goldstone theorem without Lorentz ...
- 26.8k
7
votes
1
answer
833
views
Vacuum expectation value (VEV) of a Gauge theory - Spontaneous Symmetry Breaking (SSB) - Higgs Mechanism
I am dealing with a sort of scalar QED with a term of SSB
\begin{equation}
\mathcal{L}=\left|D_{\mu} \phi\right|^{2}-\frac{1}{4}\left(F_{\mu \nu}\right)^{2}-V\left(\phi^{*} \phi\right)
\end{equation}
...
- 900
0
votes
0
answers
101
views
Physical degree of freedom and gauge fixing?
I'm confused with the gauge fixing in the Higgs mechanism.
So if we have an action like
$$S=\int |D\phi|-\frac{1}{4}F^2 -V(\phi) ~ ,\tag{1}$$
then expand around some non-trivial vacuum, then we have ...
- 311