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1 vote

Why can't we insist that the strong interactions must preserve $CP$?

The answer is pretty simple. To make $$ \bar{\theta} = \theta + Arg det M = 0 $$ you have to chirally rotate the quarks so that $$ Arg det M = -\theta $$ The chiral rotation of quarks such as $$ \psi \...
MadMax's user avatar
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2 votes

Why so much kinetic energy inside a proton?

"First, it gets some mass from the masses of its quarks, and some more from their movements. Next, it gets mass from the strong force energy that glues those quarks together, with this force ...
crimper's user avatar
  • 21
18 votes

Why so much kinetic energy inside a proton?

I'm sure the word 'quantum' will begin to show up around here, but the question that bugs me is, would it be possible, theoretically, to take the components of a proton, and very carefully place them ...
naturallyInconsistent's user avatar
33 votes

Why so much kinetic energy inside a proton?

The simplistic answer is that a proton is very small. The quarks are not free, but are confined to a small region. By the uncertainty principle a small uncertainty in the position of the quarks ...
Dale's user avatar
  • 100k
5 votes

Quark condensate and VEV of $\pi^0$

Nonono! You've made a bad hash of standard notation. The interpolating operator for the neutral pion you wrote is far too schematic/complacent, and lacks an all-important $\gamma^5$. You might ...
Cosmas Zachos's user avatar
-1 votes

Why does strong interaction increase with distance?

The strong force, described by quantum chromodynamics (QCD), is indeed a non-perturbative theory at low energies. This means that traditional perturbative techniques, which are typically used for ...
Adversing's user avatar
  • 161
2 votes

Quark Combination of Hadrons

You are confusing two different things: If you see the notation $\pi^+ = u \bar{d}$ (e.g. in the Particle Data Tables), this simply means that the quark content of a charged pion is given by an up-...
Hyperon's user avatar
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