The quark model postulates that the hadrons such as protons and neutrons have an inner structure; quarks.

learn more… | top users | synonyms (1)

0
votes
1answer
20 views

Is it possible to make use of the gluon field's energy to use is applications?

As we know most of the mass of the proton comes from the energy caused due to the interactions of the quarks with the gluon fields (reference link of this statement ...
1
vote
2answers
35 views

Where does the mass of particle that is decaying go?

The particle of a heavy quark (such a s a bottom quark) into either an up or down is an actually change I'm mass (if I know what I'm talking about, which I don't think I do, but that's what this is ...
-2
votes
0answers
38 views

Which quarks will I find in a neutron? [closed]

A: Three up quarks. B: Two up quarks and a down quark. C: Two down quarks and an up quark. D: One charm quark, one up quark and one down quark. please expain why
5
votes
1answer
322 views

Is color charge a quantum mechanical observable?

If I had 2 pions that were identical, except one was comprised of a red and anti-red, and the other was comprised of a green and anti-green, would I be able to perform an experiment that distinguishes ...
2
votes
1answer
54 views

Ratio of electrons and protons in Universe

What is the relation between amount of electrons and protons in Universe? I expect that the Universe should not be charged, so the estimation is 1:1. But then, why there should be the same amount of ...
5
votes
1answer
51 views

Why does gg fusion dominate over q qbar annihilation at the LHC?

The cross section of top quark pair production is dominated at the LHC by gluon-gluon fusion, whereas at Tevatron, quark-antiquark annihilation is more prevalent. Why is this? I know the fundamental ...
0
votes
0answers
32 views

The Interior of A Nucleon

Just like, in a Bohr model, the atom has a particular structure, what is it like inside of a Nucleon? Like, are there particular ways the quarks are arranged, and what about the binding energy that ...
2
votes
1answer
30 views

Parameterization of an arbitrary element of $U(2)_L \times U(2)_R$ (Chiral symmetry with two quarks)

When you write down the Lagrangian for two quarks : \begin{equation} \mathcal{L}_\text{QCD}^0 = -\frac{1}{4} G_{\mu\nu}^a G^{a\mu\nu}+ \bar\Psi i \gamma^\mu D_\mu \Psi \end{equation} you find an ...
1
vote
1answer
93 views

Why do the quarks constantly change colors?

In a hadron the quarks constantly change colors.They,then exchange gluons to remain color neutral.For example a red quark becomes blue by emitting a red and anti blue gluon and then the blue quark ...
1
vote
3answers
104 views

Quark anti-quark pair creation. Do we need a gluon?

What is the difference between these diagrams? Is the presence of the gluon taken for granted in the second one? and EDIT: I just zoomed into the picture, it is not a single quark state. ...
0
votes
1answer
69 views

What do quarks look like?

I've heard everything from zero-dimensional points, to squares, and I would love to know what they really look like, or if they have any physical shape.
1
vote
1answer
62 views

Where does the mass of a nucleon originate in an atom?

The mass of the three quarks in the nucleons make up only about one to two percent of the mass of the nucleons. What makes up the other 98 percent?
0
votes
1answer
49 views

Can the density of quarks be more than density of black hole? [duplicate]

I have found this list of densities here: http://wiki.chemprime.chemeddl.org/index.php/Density_of_Black_Holes and I am looking for the density of quarks but I have not found it. I was wondering if ...
5
votes
2answers
101 views

SU(3) antiquark triplet transformation

I'm reading a rather elementary particle physics text, Modern Particle Physics by Thomson. He is staying away from the heavy group theoretic stuff. He derives the transformation law for an SU(2) ...
1
vote
0answers
23 views

How to calculate U-spin for baryons

I am trying to calculate U-spin for sigma baryons. I don't know why U-spin for (sigma+) and (sigma-) and (sigma*+) is 1/2 but for (sigma*-) is 3/2? I know that (sigma+) and (sigma-) are octet and ...
1
vote
0answers
20 views

How to calculate D0->K+K- decay with QCD factorization?

I am studying the decay of D0->K+K- and I calculated the result of Branching Ratio by Naive QCD and I wrote all the equations for amplitude and branching Ration and Hamiltonian and... for this decay ...
2
votes
6answers
588 views

On the foundations of quantum physics

Quantum physics has to be validated by experiments. But experiments are to be interpreted in the context of quantum physics. Isn'it like a snake biting its own tail? For example, using a scanning ...
1
vote
0answers
32 views

What is the physical meaning of U- and V-spin?

$SU(3)$ group has three $SU(2)$ subgroups. The first one (with generators $\lambda_{1}, \lambda_{2}, \lambda_{3}$ of corresponding algebra) is called I-spin, the second one (with generators ...
2
votes
0answers
22 views

Has the formation of a new quark pair as we separate two quarks been observed or is it only a prediction? [duplicate]

Because of quark confinement we know that as we try to separate quarks appart the energy required will increase, but if the force is strong enough (I do not know if possible in the lab, but at least ...
1
vote
0answers
111 views

Simplify QCD Lagrangian

How we can derive the electric charge of the field theory for each field? For example lets say that we have the u-quarks (3-colors) and electron that we know that has charge -e) free Lagrangian ...
5
votes
4answers
1k views

What are Quarks made of and will they ever decay to this? [duplicate]

What is it that quarks are actually made of? Will they decay into this substance? As the up and down quarks are the lightest type of quark do they not decay? I was thinking that if this could happen, ...
2
votes
2answers
277 views

Is a quark bomb possible?

I am wondering about the possibility of making a bomb out of the binding energy of quarks inside hadrons. I know that about confinement and all that, but I wonder if there is a way to harness this ...
2
votes
1answer
61 views

What does the mass of a quark mean?

The mass of an electron includes the mass of the electric field it creates. If electrons have a radius, it's known to be small enough that the mass of the electric field would be more than the total ...
1
vote
1answer
93 views

What's inside a quark? [duplicate]

What particles make up a quark? We all know quarks (3, uud) make up a proton. I read on Wikipedia they are called "hadrons" ,but how do they work? Is the collection wave functions of the components ...
6
votes
2answers
161 views

Quarks falling in a black hole?

All I know about quarks is that they make up protons and neutrons and you can't really pull a quark pair apart, you just end up with 2 quark pairs because of all the energy you added becomes 2 new ...
2
votes
2answers
48 views

At what energy do up and down quarks unbind?

At what energy do up and down quarks unbind? Google does not seem to have a clear answer. Could someone please represent this mathematically?
0
votes
1answer
88 views

What would be the best way to explain color confinement in quarks? [duplicate]

To someone who is not so experienced in advanced physics, how do you explain or teach them why something as complex as color confinement prevents us from being able to see or prove that there are any ...
3
votes
0answers
47 views

How could we find preons?

If I understand correctly, scientists were able to find strong evidence for the existence of quarks by using deep inelastic scattering. If quarks (hypothetically) are composed of preons, could we use ...
0
votes
1answer
40 views

What underlying structure/framework defines the charge of an antiparticle or regular particle (specifically a proton)? [duplicate]

I can't seem to find an answer to this. For a given configuration, say for a Hydrogen atom: the proton has properties which give it a positive charge. This is a known truth. Now lets take Hydrogen's ...
0
votes
1answer
41 views

Unitarity of CKM matrix?

The CKM matrix is known to be unitary. Now, is it just found experimentally? Is the following idea correct? We know that the weak force eigenstate $ \left( \begin{array}{c} d' \\ s' \\ b' ...
1
vote
0answers
57 views

Origin of CP violation in CKM matrix?

I have already seen this question but I am not very familiar with the group theoretical framework of the Standard Model and was hoping for a more diluted answer. So I have come across this slide: ...
4
votes
2answers
174 views

Origin of quark masses

Does all the mass of the quarks in the standard model come from the Higgs sector or is there also a contribution to quark masses due to QCD chiral symmetry breaking?
2
votes
1answer
79 views

Why does the $Z$ boson not change quark flavour?

Is it just an observation from Particle Accelerators data? I was trying to understand what is it that mathematically stops the $Z$ boson from changing quark flavour, if it is known?
0
votes
1answer
45 views

Gluons, the Weak Force, or both?

I've recently been reading about how the Weak Force holds quarks together to make protons and neutrons. But before learning about that specifically, I found out about Quark-Gluon Plasma, leading me to ...
1
vote
3answers
520 views

Anti-neutrons, anti-quarks, isospin: What is observed and what is derived?

I would be a little more restrained with the existence of antineutrons. First at all - if I understood right - the existence of antiquarks is hypothetical. If one not agree with this please refer to ...
0
votes
1answer
68 views

If one is talking about antineutron production, what is the charge exchange?

In this question was given the antineutron production in the way $$ p + \bar{p} \rightarrow n + \bar{n}. $$ Internet search gives one source only where the charge exchange is mentioned. They talk ...
3
votes
1answer
311 views

Why isn't the quark charge taken as primitive?

Why are electrons taken implicitly to be the elementary charge? It would save a lot of fractions in particle physics problems.
4
votes
1answer
140 views

Electron Charge is 150%?

Is there a theory for why the charge of an electron is precisely 50% larger (magnitude) than a quark's? I have usually thought of this the other way around: the charge of a quark being 2/3 (or -2/3) ...
0
votes
1answer
32 views

Spatial configuration of quarks?

Is there anything known about the spatial configuration of the quarks within a proton of pion? Or are they just considered to be two or three overlapping points?
0
votes
1answer
67 views

Wavefunctions and Quark Confinement

While I have a decent knowledge of general relativity (and, of course, classical mechanics), I am quite a novice when it comes to quantum mechanics, so I apologize if this is a rather basic question. ...
3
votes
2answers
104 views

What is the axial transformation of a group, i.e. $SU(3)$?

The Gell-Mann matrices $\lambda^\alpha$ are the generators of $SU(3)$. Applying an SU(3) - transformation on the triple $q = ( u , d, s )$ of 4-spinors looks like this: $$ q \rightarrow q' = e^{i ...
4
votes
2answers
96 views

Can quarks of different colors annihilate?

Wikipedia: "Antiparticles have exactly opposite additive quantum numbers from particles, so the sums of all quantum numbers of the original pair are zero." Is it possible to annihilate a ...
1
vote
1answer
49 views

Does quark have fixed energy?

Does a quark, for example a up-quark has a fixed energy? The standard model gives well defined masses in MeV which is energy too.
1
vote
1answer
104 views

Pions as a superposition of quark states

in Isospin space there are two fundamental states called up and down quarks, which satisfy the following eigenvalue equations: $I u = (1/2) u$, $I d = (1/2) d$ and $I_3 u = (1/2) u, I_3 d = (-1/2) ...
1
vote
1answer
73 views

What does the size of an object have to do with it's color?

Stephen Hawking mentions in his book 'A Brief History of Time' that quarks are much smaller than the wavelength of visible light so they do not have any color in the normal sense. What exactly does ...
8
votes
1answer
100 views

Would a high energy bottom quark 'decay' to a top quark?

The reason for the long life time of $B$-hadrons is that the CKM element $|V_{tb}| > 0.999$, meaning that the preferred decay of the $b$-quark is to a $t$-quark (and vice versa). However because ...
0
votes
0answers
49 views

Why are quark up and down an isospin doublet?

I have some difficulties in understanding the isospin of quarks. As far as I am concerned, the isospin formalism is used to express the physical property of electric charge. I mean: what I know ...
4
votes
1answer
274 views

Does the Anti-Up, Anti-Strange, Anti-Strange Quark combination form a Baryon?

I was using this applet: http://www.lon-capa.org/~mmp/applist/q/q.htm And I saw that the up, strange, strange quark combination formed this Baryon: But the anti-up, anti-strange, anti-strange ...
0
votes
0answers
54 views

Quark confinement

What is the reason why quarks moving freely in confined nucleus do not radiate energy like any accelerated charge banging around in a bag? If the answer is that they have distinct energy levels like ...
4
votes
0answers
72 views

Why does strong interaction increase with distance?

I read numerous times that strong interaction increases with distance. But how can one actually derive the force-distance relation from the lagrangian (quark field + gluon field + gauge coupling)? ...