A model of the basic particles and forces featuring six quarks, three charged leptons, three massless neutral leptons and four fundamental force carrying bosons. The twelve fermions are arranged into three generations, while the bosons serve to explain the electromagnetic interaction plus the strong ...
7
votes
2answers
179 views
Particles mass determined by SO(D-2) vs SO(D-1)
I've recently come across this statement that massless particles arise from $SO(D-2)$ symetry and massive particles from $SO(D-1)$.
I would have guessed that it would be the exact opposite way, but ...
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 ...
4
votes
5answers
3k views
The Higgs field a new Luminiferous aether?
As of this writing it has been made clear to me that classical physics' Luminiferous aether was a terriblly poor discriptor of space. With the advent of Special Relativity and General Relativity, that ...
5
votes
1answer
220 views
Why are WW gg ττ branching ratios so similar for a 115 GeV SM Higgs?
In a previous question on Higgs branching ratios, I find this image
(originally from page 15 here).
I am VERY intrigued by the fact that decays to WW, gg, and ττ are almost equally probable, for ...
2
votes
2answers
266 views
Might the LHC see nothing new at all?
There's no guarantee that supersymmetry (or more exotic new physics) will be seen at the LHC. Meanwhile, it's standard lore that a Higgsless standard model becomes nonunitary somewhere in the vicinity ...
8
votes
1answer
360 views
Do color-neutral gluons exist?
If I'm correct a quark can change color by emitting a gluon. For example a blue up quark $u_b$ can change into a red up quark by emitting a gluon:
$$u_b \longrightarrow u_r + g_{b\overline{r}}$$
...
7
votes
1answer
194 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 ...
4
votes
2answers
407 views
Is the Higgs 3/4 detected already?
Can someone provide an expanded explanation on the statement that the Higgs field is already 3/4 detected?
Link to ref (@nic, sorry I left it off, do a quick search on Higgs to find the right ...
1
vote
1answer
63 views
Fine tuning and parametric modelings
When I perform parametric modeling, if there is significant multicollinearity between variables I think should be independent, but in fact are not, I run into the case where one or more of the ...
0
votes
1answer
200 views
How is fine tuning of standard model conceptual different than the fine tuning of PI?
If I were to try to find pi using a ruler and a compass, I would first try to find out how many rational line segments of the diameter I could fit around the interior circumference and then continue ...
5
votes
0answers
140 views
Chiral fermions from torsion flux in M-theory?
Witten's 1981 paper "Search for a realistic Kaluza-Klein theory" is frequently cited for its observation that, in a compactification of d=11 supergravity on a manifold with SU(3) x SU(2) x U(1) ...
0
votes
0answers
187 views
Does the Standard model allow for radioactive decay prediction? [duplicate]
Possible Duplicate:
Predicting Decay Rates via the Standard Model
More specifically, does (any) current theory allow for approximate or exact predictions of atomic decay rates and types ...
3
votes
2answers
207 views
If dark matter is a new type of particle, what does that imply?
My understanding is that dark matter cannot be (or is at least highly unlikely to be) an exotic form of any known particle. On the other hand, articles about particle accelerators seem to say that the ...
4
votes
1answer
295 views
Detection of W and Z bosons
What specific behaviour confirmed the existence of the W and Z bosons at the UA1 and UA2 experiments?
Thanks!
8
votes
4answers
409 views
strange modulation of radiactive decay rates with solar activity
Recently i found out this uber strange article about nuclear decay rates being somehow showing seasonal variations with a high correlation with sun activity. Two very precise questions:
1) has this ...
10
votes
1answer
807 views
115 GeV, 170 GeV, and the noncommutative standard model
Several years ago, noncommutative geometry was used to describe the standard model, somehow yielding a prediction of 170 GeV for the mass of the Higgs boson, a prediction which was falsified a few ...
6
votes
1answer
458 views
What is the difference between 'running' and 'current' quark mass?
When looking at the PDG, there is a difference between the 'running' and the 'current' quark masses.
Does anyone know which is the difference between these two?
13
votes
2answers
1k views
Did the researchers at Fermilab find a fifth force?
Please consider the publication
Invariant Mass Distribution of Jet Pairs Produced in Association with a W boson in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV
by the CDF-Collaboration, ...
4
votes
2answers
407 views
Predicting Decay Rates via the Standard Model
Question 7584 illustrated a procedure to forecast the decay rates of isotopes with known long average lifetimes. Lifetimes of the many U isotopes vary from micoseconds to gigayears. F has only one ...
1
vote
2answers
299 views
Gravity and the Standard Model
Gravity is ignored in the SM. The proton rest mass is ~0.938 GeV/$c^2$. LHC protons will move with 7 TeV energy, presumably with a relativistic mass about 7,450 times rest mass. A cosmic ray with the ...
3
votes
1answer
205 views
Why should the mass of leptons to be near of proton and QCD/chiral scales?
The mistery of the mass of the top being in the electroweak scale can be justified by the Higgs mechanism itself; in some sense the top mass is the only "natural" mass, the other masses of fermions ...
4
votes
4answers
544 views
Why are neutrino oscillations considered to be “beyond the Standard Model”?
Is this just a historical artifact - that the particle physics community decided at some point to call all of the pre-oscillation physics by the name the "Standard Model"? The reason I ask is because ...
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
912 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, ...
5
votes
2answers
486 views
Other possible theories (other than string theory) which are generalizations of the standard model with incorporation of gravity
The only finite mathematical framework that incorporates both the standard model of particle physics and gravity under one umbrella that I am aware of is string theory. I would like to know whether ...
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 ...
1
vote
2answers
249 views
Is there a relationship between Berry-Pancharatnam phase and CP violation in quark mixing?
Berry-Pancharatnam phase is the phase that quantum systems exhibit when they pass through a sequence of states and return to their original state. It's a complex phase and it is different from the ...
7
votes
2answers
500 views
Why do leptons and quarks mix?
Is the fact that weak eigenstates are not mass eigenstates completely arbitrary? Or is there a deeper reason for the existence of the PMNS and CKM matrices?
4
votes
2answers
444 views
“Space” in General Relativity and “vacuum” in Standard Model, is it the same thing?
And expansion of space is equal to expansion of vacuum?
14
votes
7answers
1k views
What Do We Get From Having Higher Generations of Particles?
Background: I have written a pop-science book explaining quantum mechanics through imaginary conversations with my dog-- the dog serves as a sort of reader surrogate, popping in occasionally to ask ...
32
votes
5answers
2k views
Why do we think there are only three generations of fundamental particles?
In the standard model of particle physics, there are three generations of quarks (up/down, strange/charm, and top/bottom), along with three generations of leptons (electron, muon, and tau). All of ...
4
votes
1answer
667 views
Why are there 3 quarks in proton?
A few quark related questions (I don't knowmuch about them other than there are 2 flavours concerning protons and neutrons)
Why are there 3 quarks in a proton or neutron? Why not 2 or 4?
Is there an ...
11
votes
3answers
880 views
Why are quark types known as flavors?
There are six types of quarks, known as flavors.
Why where these types called flavors?
Why do the flavors have such odd names (up, down, charm, strange, top, and bottom)?
19
votes
5answers
1k views
Could gravity be an emergent property of nature?
Sorry if this question is naive. It is just a curiosity that I have.
Are there theoretical or experimental reasons why gravity should not be an emergent property of nature?
Assume a standard model ...
8
votes
2answers
306 views
Do current models of particle physics explain the chemical properties of elements/compounds?
I have a particle system of seven protons and seven (or sometimes eight) neutrons (each formed by their appropriate quarks, etc.) bound together in a state that can be macroscopically described as a ...
28
votes
4answers
2k views
What is needed to claim the discovery of the Higgs boson?
As I understand the Higg's boson can be discovered by the LHC because the collisions are done at an energy that is high enough to produce it and because the luminosity will be high enough also.
But ...
15
votes
2answers
1k views
If the LHC doesn't find the Higgs Boson, what would be the implications for the Standard Model?
What would be the implications to the Standard Model if the Higgs Boson hadn't been found with the LHC?
Also, if the Higgs Boson had not been found with the LHC, would it have been successfully ...
