# Tagged Questions

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

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### What is cause of quantization of charge? [duplicate]

What is cause of quantization of charge? When we rub two objects only an integral number of electrons or charges can be transferred is this the reason? Why electron has the smallest possible charge? ...
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### What maximum energy can be stored in a gluon field flux tube

Question is as clear as stated in title. What is the maximum energy that can be stored in a gluon field flux tube without production of an quark anti-quark pair? And how much it usually store in a ...
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### What are the six quark mass values when extrapolated to Planck energy?

Let us assume that the standard model is correct up to Planck mass. (Yes, I know, this is a big assumption.) If we continue the running of quark masses with energy (due to renormalization), what are ...
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### Quarks in a hadron- where does the mass come from

We know that the sum of the masses of the quarks in a proton is approximately $9.4^{+1.9}_{-1.3}~\text{MeV}/c^2$, whereas the mass of a proton is $\approx931~\text{MeV}/c^2$. This extra mass is ...
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### Can the up quark still be massless?

It used to be commonly discussed that the bare mass of the up quark can be $0$. This was because we can't observe its effect directly. To my knowledge the up quark can only be measured by its effect ...
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### Quark model in particle physics

As we all know that baryons are made up of three quarks while mesons are made up of a quark and an anti-quark. Is it possible for a particle to exist with five or seven quarks? Can a particle exist ...
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### Collision symmetry and measuring the asymmetry in the Drell-Yan process

I saw a talk the other day about an asymmetry in the Drell-Yan process caused by CP-violation: Apparently one way this can be measured (ATLAS is doing this) is to collide protons and observe the ...
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### Can quarks be considered real and elementary?

In our current theories all hadrons are made up of quarks and gluons. This view reduces considerably the big family of hadrons by providing a very logical structure in which all quantum properties ...
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### What makes neutron heavier than a proton? [duplicate]

The mass of proton is 1.672*10¯²7 kg while it is 1.675*10¯²7 kg. Both are made up of 3 quarks each. Then what makes proton lighter than a neutron?
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I wanted to know what is the Feynman rules for current-current vertex like this one: $${\cal{ L}} = G^\prime_F \hspace{2mm} \bar{d} \gamma^\mu (1-\gamma^5) u\hspace{3mm} \bar{s}\gamma_\mu (1-\gamma^... 2answers 229 views ### How and why the phrase “quark force increases with distance”? I have seen that phrase "force between quarks increases with distance" at many resources, some even relatively credible (albeit written for general audience). What is the reason behind that, when ... 3answers 245 views ### The Makeup of the Pentaquark Why is it that when they have the artist's rendition of the Pentaquark it shows two downs, two ups, and one anti-strange quark? Is this or is this just for show? Follow up to this question: if this ... 0answers 102 views ### How do quarks have no spatial extent? I found an answer to a question I had and that is that quarks have no spatial extent. But how is that possible? Everything has to have some spatial extent; to keep continuing on and on, right? 2answers 254 views ### Pentaquark spin prediction Is there a straightforward way to see what the spin of the recently-discovered pentaquark states should be, from the representation theory of SU(3)\times SU(2)\subset SU(6)? I can see that from the ... 1answer 181 views ### How many combination can quarks form? How many different combinations can quarks produce? E.g. 2 up quarks + 1 down quark = proton. Is this value going to be infinite? 0answers 22 views ### heavy quark pair spin states Apparently, heavy quark pair can have "axial-vector" spin state, "vector" spin state, and two different "tensor" spin states. Can anyone explain to me what they are and why this is the case? Thank ... 1answer 59 views ### Is there a theoretic temperature where single quarks might become individually stable? This question is what lead me to ask this. Strong force between quarks that are out of causal contact and my understanding of the standard model is that the answer is no - but the standard model ... 1answer 88 views ### Strong force between quarks that are out of causal contact This is a rather artificial scenario, but it has been bugging me lately. Background Due to the confinement in QCD, quarks are bound in color-neutral configurations. Any attempt to separate a quark ... 1answer 204 views ### Particle Physics Decay Question - Eta Prime Decay Parity/Angular Momentum Conservation I was hoping someone could clarify why the following decay does not occur:  \eta ^{'0} \rightarrow \pi ^{0} + \rho ^{0} The quark compositions and spin parity are as followed:  \eta ^{'0} : (u\... 1answer 277 views ### What is the motion of quarks inside nucleons? [duplicate] Nucleons consist of quarks which are charged particles. Proton has the quark content of uud and neutron of udd. So, it may be visualized that the down quark always remain between the up quarks inside ... 1answer 33 views ### Quark decay implies particle decay? For example, since$$s\rightarrow u+\overline{v_e}+e^{-}$$, then sticking a \overline{u} next to the quarks (s and u) we get$$s\overline{u}\rightarrow u\overline{u}+\overline{v_e}+e^{-}, ...
Problem: Prove that the reaction $p+p\rightarrow p+K^+$ is impossible, where $p=\text{proton}$, $K^+=\text{kaon}$. (Side question: Is there a specific name for a positive Kaon, just like a "positive ...