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Kinetic energy of quarks and mass of proton

I assume the energy carried by the gluons is referring to the binding energy of the three quarks by the strong force. It is more complicated than this. See how the strong interaction is figuratively ...
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Is there a law stating why a quark never decays weakly into a quark of the same weak-isospin ($T_3$)?

The law is called: "There are no flavor-changing neutral currents", given the association of $T_3$ with electric charge—the hyper charge remaining invariant, naturally. At tree level, it ...
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Is there a law stating why a quark never decays weakly into a quark of the same weak-isospin ($T_3$)?

The term in the standard model lagrangian which couples quarks of different flavors looks like $$(\overline{u}_L,\overline{c}_L,\overline{t}_L)\gamma^\mu V_{CKM} \begin{pmatrix}d_L\\s_L\\b_L\end{...
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1 vote
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$\rho$ and $\omega$ mesons decays

In particle physics, a rho meson is a short-lived hadronic particle that is an isospin triplet The isospin of the omega meson is zero In nuclear physics and particle physics, isospin (I) is a ...
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$\rho$ and $\omega$ mesons decays

The $\rho$ forms an isospin triplet ($I=1$)and the $\omega$ is an isospin singlet ($I=0$). The $g$-parity $$ g= Ce^{i\pi I_2} $$ that determines the odd versus number of pions in the decay goes ...
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1 vote

Does the Higgs field have an energy?

Higgs field is the result of a charged scalar field (where scalar means that it has no spin, charged means that it has a charge for the interaction you want to give mass) which oscillates around a ...
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1 vote

Why does the Strange Quark have Strangeness -1?

The sign of additive quantum numbers is set up to a convention. Take for example the case of the electric current: we use to say in electronics that current is a positive flow of charge, that is a ...
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4 votes

Why does the Strange Quark have Strangeness -1?

From the Wikipedia article Strangeness: The terms strange and strangeness predate the discovery of the quark, and were adopted after its discovery in order to preserve the continuity of the phrase; ...
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Is Lepton Flavour Universality an accidental symmetry of the Standatd Model?

In the Standard Model of particle physics the three charged leptons are identical copies of each other, apart from mass differences, and the electroweak coupling of the gauge bosons to leptons is ...
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2 votes
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Is Lepton Flavour Universality an accidental symmetry of the Standatd Model?

It is not accidental, at least in the sense that this term is used. The accidental symmetry is the symmetry that is forced on you by the renormalizability - i.e. for a given field set you can't write ...
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1 vote

Is color charge a quantum mechanical observable?

Usually, the charge we refer to in QFT means the Noether charge of some global (i.e physical) symmetry. For example, the Noether charge associated with a global $U(1)$ transformation in QED is called ...
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What does it mean for the $\textbf{B}$-field (Hypercharge) to be in the 0 representation within the SM?

This is just a notational issue - for non-Abelian groups, we often label their representations by their dimension $n$ as $\mathbf{n}$. For the Abelian $\mathrm{U}(1)$, all representations are one-...
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Can Higgs particles move faster than the speed of light in the high energy (temperature) regime?

Can Higgs particles move faster than light if the temperature/energy is high enough? No.
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2 votes
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Confused about helicity suppression in the decay $\pi^- \rightarrow \mu^- \overline{\nu}_\mu$

There are literally dozens of questions on this site dealing with chirality (Lorentz-invariant, but violated by masses) and helicity (conserved, but not Lorentz invariant). They are very hard to ...
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4 votes

What is the Mathematical description of Weak Interaction at low energies?

... how can I study the weak interaction separated from strong interaction and eletroweak unification? You cannot. It is impossible, for a good reason. At very low energies, the weak interactions ...
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3 votes
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In the unified electroweak theory, do the gauge bosons couple to right handed states?

Absolutely (yes)! While the charged current weak interactions, mediated by the W bosons, only coupled to left-chiral fermions (and right chiral anti fermions), both the EM and the neutral current weak ...
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1 vote
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Charged current $e^-e^+$ weak interaction Feynman diagram

Observe the fields in your lagrangian density $$ \mathcal{L}_{int}^{CC} = \frac{g}{2\sqrt{2}}\left[ \bar{\psi}_{\nu_e}\gamma^{\mu}(1-\gamma_5)\psi_e W^{+}_{\mu}+J^{\mu \dagger}\bar{\psi}_e\gamma^{\mu}(...
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