Why Do Hadrons Weigh More Than the Sum of Their Quarks?

In summary: Gluons are constantly being exchanged and created within the proton, and there is no limit to the number that can exist at any given time. However, the average number of gluons within a proton is estimated to be around 2-3, depending on the energy scale at which it is measured. This number is not precise and can vary. In summary, the extra mass of a hadron comes from the energy present in the system, and there is no simple formula for calculating the mass of hadrons from their quark components. Additionally, the number of gluons within a proton is not a fixed quantity and can vary.
  • #1
roberto85
53
0
why is it that a composite particle such as a hadron have a mass which is more than the combined rest mass of it's components? For example the proton has mass 938.27... MeV/c^2 whereas the quarks have masses only totalling approximately 8-12MeV/c^2?

I assume there is a formula used to calculate the combined mass of these particles, if so could someone please let me know it? Id like to be able to use it to be able to calculate masses of mesons and baryons from their quark components. Many thnaks
 
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  • #2
roberto85 said:
why is it that a composite particle such as a hadron have a mass which is more than the combined rest mass of it's components? For example the proton has mass 938.27... MeV/c^2 whereas the quarks have masses only totalling approximately 8-12MeV/c^2?

The extra mass comes from the energy present in the hadron (recall E=m c^2). It's a relativistic, highly energetic system.


roberto85 said:
I assume there is a formula used to calculate the combined mass of these particles, if so could someone please let me know it? Id like to be able to use it to be able to calculate masses of mesons and baryons from their quark components.

Sounds great. I'd like that too! Unfortunately, our tools for calculating things non-perturbatively in QCD are extremely limited, and the masses of hadrons are not quantities that can be calculated in perturbation theory. The only method that I know of that can be used for such a thing is http://en.wikipedia.org/wiki/Lattice_QCD" , which is extremely computationally expensive, but has already been used successfully to calculate the mass of, e.g., a proton. There's definitely no simple analytic formula, as nice as that would be.
 
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  • #3
oh yes lattice qcd. another question is how many gluons are in a proton?

the_house said:
The extra mass comes from the energy present in the hadron (recall E=m c^2). It's a relativistic, highly energetic system.




Sounds great. I'd like that too! Unfortunately, our tools for calculating things non-perturbatively in QCD are extremely limited, and the masses of hadrons are not quantities that can be calculated in perturbation theory. The only method that I know of that can be used for such a thing is http://en.wikipedia.org/wiki/Lattice_QCD" , which is extremely computationally expensive, but has already been used successfully to calculate the mass of, e.g., a proton. There's definitely no simple analytic formula, as nice as that would be.
 
Last edited by a moderator:
  • #4
roberto85 said:
oh yes lattice qcd. another question is how many gluons are in a proton?

A proton does not have a definite number of gluons.
 

What are subatomic particle masses?

Subatomic particle masses refer to the mass of particles that make up atoms, such as protons, neutrons, and electrons. These particles are extremely small and have a minuscule mass compared to larger objects.

How are subatomic particle masses measured?

Subatomic particle masses are measured using a unit called atomic mass units (amu). This unit is based on the mass of a single proton or neutron, which is approximately 1 amu. Scientists use techniques such as mass spectrometry and particle accelerators to measure the masses of subatomic particles.

What is the most massive subatomic particle?

The most massive subatomic particle is the top quark, which has a mass of approximately 173 GeV/c2 (gigaelectronvolt per speed of light squared). This is much larger than the masses of other particles, such as protons and neutrons, which are around 1 GeV/c2.

Do all subatomic particles have mass?

No, not all subatomic particles have mass. Photons, which are particles of light, do not have a rest mass. They only have a mass when they are moving at the speed of light, as described by Einstein's theory of relativity.

Why is understanding subatomic particle masses important?

Understanding subatomic particle masses is important because it helps us understand the fundamental building blocks of matter and the forces that hold them together. It also has practical applications in fields such as nuclear energy, particle physics, and medical imaging.

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