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 ...

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3
votes
2answers
193 views

$\left(H^\dagger H\right)^2$ is invariant under $U(1)\times SU(2)$?

Is it true that $\left(H^\dagger H\right)^2$ is invariant under $U\left(1\right) \times SU\left(2\right)$ where $H$ is the Higgs field $(1,2,1/2)$? Does this invariance imply that its hypercharge ...
3
votes
2answers
914 views

What is difference between the different 'flavours' of neutrinos?

Moreover, how-come scientist know that muon-neutrino are different from electron-neutrino when they didn't even know what the difference was? Did they interact differently with other particles?
2
votes
1answer
187 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?
1
vote
1answer
1k views

Quark Radius Upper Bound

If quarks had internal structure (contradicting current beliefs), what is the lowest upper bound on their "radius" based on current experimental results? If possible, I'd prefer to only consider ...
1
vote
2answers
405 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 ...
0
votes
0answers
50 views

Size of an elementary particle [duplicate]

Do we have a well defined mathematical expression denoting the size of a fundamental particle with no internal structure (electron for example) ? If we do, how does it fit in with the uncertainty ...
0
votes
1answer
110 views

Why doesn't a changed particle ever lose energy by interacting with others by radiation of virtual photons? Are all virtual photons exchanged?

I've had it explained to me in a separate post that charged particles are constantly exchanging virtual particles with other charged particles and their energy is a steady state. How it is a surety ...
0
votes
2answers
328 views

Energy of quarks and the mass of the proton

We know that energy of quarks inside the proton can not be exactly fixed because if it,the 'proton decay' must not be exist. My question is if the energy of quarks inside the proton is not exactly ...
0
votes
1answer
171 views

Symmetry groups [closed]

I am quite new to this subject. I am just repeating in a few words, what I have learned so far: There are 4 fundamental forces of nature: strong, weak, electromagnetism and gravity. Physicists are ...
0
votes
1answer
609 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
1answer
58 views

What mechanism produced the baryon excess in the universe?

A baryon is a composite subatomic particle made up of three quarks (as distinct from mesons, which comprise one quark and one antiquark). Baryons and mesons belong to the hadron family, which are the ...
-3
votes
1answer
427 views

Pion Decay and Fractional electric Charge disappeared, why?

Since the charged pions decay into two particles, a muon and a muon neutrino Fractional electric Charge disappeared, why? The decay proceeds by the weak interaction $W^{+}$ and can be visualized in ...