Tagged Questions
9
votes
0answers
87 views
infrared free QED and Higgsless standard model phenomenology
This is one of those "what if" fantasy world type questions. I like hard sci-fi so please no "well, you changed one thing about the world so now anything goes." :)
What if the Higgs had no vev?
That ...
1
vote
1answer
73 views
How to find the Higgs coupling with a mixing matrix?
It is known that the couplings to the Higgs are proportional to the mass for fermions;
$$g_{hff}=\frac{M_f}{v}$$
where $v$ is the VEV of the Higgs field. I'm trying to figure out why this is true ...
4
votes
1answer
39 views
Higgs VEV in terms of measurements on an ensemble?
Let $A$ be a Hermitian operator corresponding to some observable. If we prepare $N$ identical systems in the state $\psi$ and measure this observable in each system, the average of the measurements ...
1
vote
0answers
91 views
Mirror Matter Hypothesis?
What is the current state of the hypothesis of mirror matter today?
Are there any experimental data or theoretical arguments that exclude it by now, or is it still considered viable among physicists?
...
5
votes
0answers
52 views
Does the Standard Model plasma develop a spontaneous magnetisation at finite temperature?
Reference: arXiv:1204.3604v1 [hep-ph] Long-range magnetic fields in the ground state of the Standard Model plasma.
Alexey Boyarsky, Oleg Ruchayskiy, Mikhail Shaposhnikov.
The authors of this paper ...
4
votes
0answers
95 views
Does the Standard Model have a Landau pole?
I have seen the statement that the Standard Model has a Landau pole, or at least it its believed that it does at $\sim 10^{34}$ GeV. Has this actually been proven (at least in perturbation theory, as ...
5
votes
0answers
113 views
Are QFT solitons expected to represent standard model particles? Or strings?
Is work on solitons in QFT's focused on finding solutions that could represent the fundamental particles of the Standard Model, or is the work focused on finding particles Beyond The Standard Model? ...
2
votes
0answers
113 views
Do all the particles acquire mass in the Standard Model due to the Higgs mechanism only?
I know that a mass term for an intermediate boson is not compatible with the gauge symmetry. But in principle a mass term for the electron field does not violate a gauge symmetry. However to build an ...
1
vote
2answers
177 views
What is the expectation value of the number operator when the vacuum has a VEV?
The number operator N applied to a field whose vacuum has zero VEV gives $N|0>=0$. What if we apply it to the Higgs field?
The background of this question is that in popular scientific accounts, ...
3
votes
1answer
259 views
What is the hierarchy problem?
BACKGROUND
So far I understood that the hierarchy problem was the large difference between the gravitational scale, $M_{pl}\sim 10^{18}\; [GeV]$, compared with the electroweak scale, $M_{ew}\sim ...
4
votes
3answers
226 views
Do strong and weak interactions have classical force fields as their limits?
Electromagnetic interaction has classical electromagnetism as its classical limit. Is it possible to similarly describe strong and weak interactions classically?
2
votes
2answers
192 views
Fermion Field of Standard Model
Why fermion field is treated as anti-commuting and boson field as truly classical in standard model?
3
votes
1answer
230 views
What's the deepest reason why QCD bound states have integer charge?
What's the deepest reason why QCD bound states have integer electric charge, i.e. equal to an integer times the electron charge?
Given that the quarks have the fractional electric charges they do, ...
0
votes
1answer
260 views
What is the relationship between the Higgs field and quarks?
I have some difficulty considering the relative size of each and the meaning behind the shape of Higgs boson. I ask relating to the structures of both the Higgs field and quarks. How is it that the ...
0
votes
0answers
95 views
What would the universe be like if Electroweak symmetry were unbroken? [duplicate]
Possible Duplicate:
What happens to matter in a standard model with zero Higgs VEV?
What if the Higgs did not have a "Mexican hat" potential and the therefore it's vacuum expectation value ...
4
votes
0answers
109 views
Relation among anomaly, unitarity bound and renormalizability
There is something I'm not sure about that has come up in a comment to other question:
Why do we not have spin greater than 2?
It's a good question--- the violation of renormalizability is linked
...
1
vote
1answer
116 views
Lepton masses in the Standard Model
Some simple questions regarding leptonic masses in the Standard Model (SM):
Why there is not an explicit mass term in addition to the effective mass term that arises from the Yukawa terms after ...
2
votes
2answers
98 views
Charges of quarks and leptons
Are there any theoretical restrictions within the framework of QFT that fix the relative sign between charged leptons and up-type quarks?
We know that in our universe, they have opposite signs -- ...
3
votes
0answers
268 views
On the naturalness problem
I know that there are several questions about the naturalness (or hierarchy or fine-tunning) problem of scalars masses in physics.stackexcange.com, but I have not found answers to any of the following ...
4
votes
0answers
105 views
What is the rate of B violation expected in the standard model during high energy collisions?
In a recent question Can colliders detect B violation? I asked about detecting B violation in collisions. Here I am interested in the theory aspect. (I asked both questions originally in the same ...
5
votes
2answers
228 views
How does Annihilation work?
I'm wondering why matter and antimatter actually annihilates if they come into contact. What exactly happens? Is that a known process? Is it just because of their different charges? Then what about ...
2
votes
1answer
216 views
Higgs potential
The potential for the Higgs field is standard a quartic one (Mexican hat). Is this done for simplicity or are there fundamental reasons for this choice? I can imagine further contributions to this ...
0
votes
1answer
152 views
How to calculate Rest Mass practically with Standard Model?
With relativistic physics, we can apply force to see resistance against acceleration. It'd give us relativistic mass and we have well established formula to get to the Rest Mass as long as we know the ...
3
votes
2answers
496 views
Does Dark Matter interact with Higgs Field?
Dark matter does have gravitational mass as we know from its discovery. Does it have inertial mass?
4
votes
2answers
380 views
Is the Higgs a quantum field or a particle?
The Higgs is not detected in the asymptotic data, so it is possible that there is no particle interpretation for the Higgs quantum field. Indeed, the Higgs potential is only positive definite if the ...
1
vote
1answer
357 views
Origin of the Higgs field
Are there any attempts in the literature at addressing the origin of the Higgs field? And, which lines of research that find it inevitable to address this question?
1
vote
1answer
129 views
Particle mixing and indistinguishability
Neutral kaons have two flavor combinations: $\mathrm{d}\bar{\mathrm{s}}$ and $\mathrm{s}\bar{\mathrm{d}}$. They can also be weak eigenstates: $\mathrm{\frac{d\bar{s} \pm s\bar{d}}{\sqrt{2}}}$.
But ...
5
votes
1answer
256 views
How do physicists know that mass of possible Higgs particle is limited between two values?
How do physicists know that mass of possible Higgs particle is limited between two values 90 GeV/c$^2$ and 145 GeV/c$^2$?
8
votes
4answers
2k views
Why don’t photons interact with the Higgs field?
Why don’t photons interact with the Higgs field and hence remain massless?
2
votes
1answer
185 views
In SUSY why does electroweak symmetry breaking only happen in the SM sector?
This is a difficult question to phrase succinctly, so I hope the title makes sense. What I want to understand is what seems like a lack of symmetry (besides SUSY-breaking) between the SM sector and ...
16
votes
1answer
224 views
Why is there no theta-angle (topological term) for the weak interactions?
Why is there no analog for $\Theta_\text{QCD}$ for the weak interaction? Is this topological term generated? If not, why not? Is this related to the fact that $SU(2)_L$ is broken?
18
votes
2answers
160 views
Values of SM parameters at one certain scale
The general question is:
What are the values of Standard Model parameters (in the $\bar{MS}$ renormalization scheme) at some scale e.g. $m_{Z}$? As its parametrization in Yukawa matrices is not unique ...
2
votes
1answer
170 views
Why are the quarks so named?
Quarks have a variety of names (or flavours):
Up
Down
Strange
Charm
Bottom or Beauty
Top or Truth
Why do they have such odd names?
2
votes
1answer
201 views
If LHC searches of a Higgs boson won't be a success, what consequences for the theory of electroweak interaction it can bear?
Whether it is necessary to search still for variants of an explanation of spontaneously breaking gauge symmetry, giving masses for a W, Z-bosons?
Goldstone bosons are bosons that appear necessarily ...
6
votes
4answers
265 views
AQFT and the Standard Model
The German physicist Rudolf Haag presented a new approach to QFT that centralizes the role of an algebra of observables in his book "Local Quantum Physics". The mathematical objects known as operator ...
7
votes
3answers
657 views
Left and Right-handed fermions
Is there a simple intuitive way to understand the difference between left-handed and right-handed fermions (electrons say)?
How to experimentally distinguish between them?
3
votes
0answers
95 views
How does one place QFT's reality in context with that of other areas of physics? [closed]
Okay, so I'm learning some QFT, I read through Bogoliubov, Shirkov Introduction to Quantized Fields up to the section on renormalization, and then wanted to see a more modern point of view- so I ...
7
votes
1answer
192 views
Is there literature on a continuous mass spectrum for the Higgs field?
Various masses for the Higgs field are compatible with experiment, but is it possible that the Higgs field is not observable because it has a continuous mass spectrum?
Work in the 60s and 70s on free ...
10
votes
1answer
987 views
What are the alternatives to the Higgs mechanism?
Can someone summarize, with references if possible, all of the alternatives to the simplest model (that requires only a single scalar Higgs field with the Mexican Hat potential) of spontaneous ...
13
votes
4answers
911 views
What is the need for the Higgs mechanism and electroweak unification?
The Higgs mechanism allows massless fields to acquire mass through their coupling to a scalar field. But if the masses cannot be predicted because the couplings have to be fixed, what really is the ...
11
votes
5answers
2k views
Are W & Z bosons virtual or not?
W and Z bosons are observed/discovered. But as force carrying bosons they should be virtual particles, unobservable? And also they require to have mass, but if they are virtual they may be off-shell, ...
15
votes
6answers
2k views
Why should the Standard Model be renormalizable?
Effective theories like Little Higgs models or Nambu-Jona-Lasinio model are non-renormalizable and there is no problem with it, since an effective theory does not need to be renormalizable. These ...
10
votes
2answers
2k views
Shape of the Higgs branching ratio to ZZ
I've been looking at the, now very popular, graph of the SM Higgs decay branching ratios:
You see that the ZZ branching ratio has a funny dip around the $170\, GeV$, very different from the WW ...
