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If you look at the standard model you will only find gluons. This is very clear and should settle any doubts. (Pions are a historical relic of the middle of the twentieth century which only provide an approximation.)

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I imagine that the simplest experiment you could do to show the non-specialist would be measuring the pion charge ratios near the pion-production threshold on the first few light targets ($^1\mathrm{H}$, $^2\mathrm{H}$, $^3\mathrm{He}$ $^4\mathrm{He}$). That is we're looking at the reactions \begin{align} e^- + {}^Z\!A &\longrightarrow e^- + ... 11 The centripetal acceleration that the protons feel as they circulate in the LHC is roughly: a = \gamma^2 \frac{v^2}{r}  This is the usual equation for centripetal acceleration but multiplied by a factor of $\gamma^2$ to allow for the time dilation the protons experience. The speed $v$ is approximately $c$. The radius of the LHC is about 4.3km but the ...

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Looking at the literature, and please tell me if I am wrong, it seems that the yukawa couplings fail to unify. This seems to counter the intuition that all the particles in a multiplet should have the same mass, but surely it can be argued that the mass of the multiplet is zero until the higgs mechanism is activated. (Still, comments are welcome about this; ...

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If we continue the running of quark masses with energy (due to renormalization), what are the mass values we get for the six quarks at Planck energy? Is the sequence of mass values the same at Planck energy or do some quarks "catch" up with others? Here is the definition of Planck energy: Note the 10^19GeV. The electroweak symmetry breaking is at ...

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I think that your idea of mass is a little wrong. The quark mass is given in a renormalization scheme, if you change it you would have different masses for quarks. But for example the pair production is a physical process, in fact, if you do a pair production with all the radiative corrections you will find the same energy with whatever renormalization you ...

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You say: Now, when we talk about energetically favourably bound systems, they have a total mass-energy less than the sum of the mass-energies of the constituent entities. and this is perfectly true. For example if we consider a hydrogen atom then its mass is 13.6ev less than the mass of a proton and electron separated to infinity - 13.6eV is the ...

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This happens because of a property of the strong force, called Asymptotic Freedom. This causes the interaction between quarks to get asymptotically weaker as the distance between them decreases. This is the reason why quarks are always found in a bound state and are not freely available in nature. The strong force confines quarks to a region where they ...

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My own impression is that the ball got stuck in someone' roof, but I am partial because some of my numerology did coincide with the relationship $(m_u,m_d,m_s) \propto (0, 2 - \sqrt 3, 2+\sqrt 3)$ proposed by Harari Haut Weyers (1978) (presented by Harari here) when trying to find some first-principled calculation of Cabibbo angle. My understanding is that ...

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This admittedly, isn't much of an answer, as I'm merely repeating information from the Particle Data Group page about the up-quark, which I consider up-to-date. Their current combination is that $m_u = 2.3^{+0.7}_{-0.5}\,\text{MeV}$, but they warn that The $u$-, $d$-, and $s$-quark masses are estimates of so-called "current-quark masses," in a ...

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Since you asked this question there have been a couple of confirmation of exotic particles which consist of four or more quarks. For example, Z(4430) recently observed in LHCb, was already discovered by Belle long time ago. This exotic particle has a $c\bar{c}d\bar{u}$ quark structure. This would lead us to think how color confinement would be satisfied? As ...

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