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 ...
4
votes
3answers
569 views
Why are there 4 Dimensions and 4 Fundamental Forces?
Is it a coincidence that there are four fundamental forces and four spacetime dimensions ? Does a universe with three spacetime dimension contain four fundamental forces? Can magnetism be realized in ...
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 ...
3
votes
3answers
148 views
What barriers exist to prevent us from turning a baryon into a anti-baryon?
At present the only way we can produce anti-matter is through high powered collisions. New matter is created from the energy produced in these collisions and some of them are anti-matter particles ...
2
votes
1answer
130 views
Similar masses and lifetimes of the $\Delta$ baryons
Why do the four spin 3/2 $\Delta$ baryons have nearly identical masses and lifetimes despite their very different $u$ and $d$ quark compositions?
2
votes
1answer
334 views
Why does the Higgs field only couple to opposite-chiralities fermions?
According to the Wikipedia page on the Standard Model, the Higgs field interact with fermions through a Yukawa interaction coupling only left to right chiralities. What is the reason for that? Is that ...
3
votes
1answer
467 views
What's the Standard Model width of a 125 GeV Higgs?
There's a fairly broad mass spread in the new results out of Atlas and CMS. I'm curious how this fits with the expected SM width.
2
votes
1answer
171 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
0answers
188 views
Has CERN recently found evidence for a Z-prime boson?
In the recent Higgs seminar at 73:38 Guido Tonelli the spokesman for CMS, makes a mistake and refers to a Z-prime in a context that would imply that they see them frequently. He swiftly backpedals ...
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 ...
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 ...
3
votes
2answers
577 views
Are quarks and leptons actually fundamental particles? [duplicate]
Possible Duplicate:
What are quarks made of?
Are quarks and leptons actually fundamental, or are they made up of even more fundamental particles? And is it true that many consider quarks ...
-1
votes
1answer
169 views
How to verify a standard model correct or not? [closed]
How to verify a standard model correct or not?
which data can be applied to standard model to see its effect, and where can find these data?
could you demonstrate how to apply it
5
votes
1answer
353 views
Is there a concise-but-thorough statement of the Standard Model?
I’m a grad student in high-energy physics. I’m familiar enough with the Standard Model, but I’ve always wondered whether there existed a canonical statement of, effectively, “what we talk about when ...
1
vote
1answer
100 views
What lepton neutrino would be in this reaction?
If I have a reaction (shown below), and I'm supposed to work out what the products will be, what would the lepton neutrino $\nu$ be? e.g electron neutrino:
$$ \nu + p \to $$
2
votes
1answer
191 views
Do neutrinos 'become' other types of particles between oscillations?
In light of the recent kurfuffle of FTL neutrinos I wonder, do neutrinos 'become' other particles between their oscillations between the different flavors of neutrino? I'm slightly familiar with ...
0
votes
0answers
83 views
Masses of all the particles in the Standard Theory [duplicate]
Possible Duplicate:
If photons have no mass, how can they have momentum?
I'm sure this question has been asked here before but I wasn't able to find it clearly answered in one q/a session. ...
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 ...
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 ...
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 ...
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 ...
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 ...
4
votes
1answer
296 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!
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 ...
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 ...
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 ...
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 ...
4
votes
4answers
546 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 ...
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 ...
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 ...
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 ...
7
votes
2answers
501 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?
11
votes
3answers
881 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)?
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 ...
4
votes
2answers
445 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?
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 ...
4
votes
1answer
669 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 ...
