Does E=mc^2 apply to the proton

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SUMMARY

The discussion centers on the application of Einstein's equation E=mc² to protons, emphasizing that the proton's rest mass primarily consists of energy. It clarifies that the mass of a system, such as a proton made of three quarks, is not merely the sum of the individual masses but includes kinetic and potential energies. The conversation highlights that while a photon possesses energy, it lacks rest mass, illustrating that energy does not equate to rest mass. The distinction between rest mass and energy content is crucial for understanding particle physics.

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  • Understanding of Einstein's equation E=mc²
  • Basic knowledge of particle physics, specifically quark composition
  • Familiarity with concepts of kinetic and potential energy
  • Knowledge of the properties of photons and their relationship to mass
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  • Research the implications of E=mc² in particle physics
  • Study the composition and properties of protons and quarks
  • Explore the differences between rest mass and relativistic mass
  • Learn about the role of energy in particle interactions
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Students and professionals in physics, particularly those focused on particle physics, energy-mass equivalence, and the fundamental properties of matter.

ftr
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Most of the proton REST mass is energy anyway. So how does that work?
 
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In general, the mass of a system of particles (e.g. the proton which is a system of three quarks) is not the sum of the masses of the constituent particles.

The total energy of the system equals the sum of (a) the rest-energies E0 of the constituent particles (which correspond to their individual masses via E0 = mc2), (b) their kinetic energies, and (c) the potential energy of the system. The total energy corresponds to the mass of the system via E = mc2, if the system "as a whole" is at rest, i.e. if the total (vector) momentum is zero.

(By "mass" I always mean what is often called "rest mass.")
 
ftr said:
Most of the proton REST mass is energy anyway. So how does that work?

This doesn't make any sense.

A photon has energy, yet it has no rest mass! So having energy does NOT automatically equate to having rest mass.

A rest mass has an EQUIVALENT energy content. But an object such as a proton does NOT just have "energy content". It may have other properties as well, such as charge, spin... and yes, rest mass.

Zz.
 

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