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I'm trying to conceptualize the mechanism of which the quarks of the baryons and mesons themselves lose energy due to binding energy.

Traditionally, mass defect is explained as the net energy released from liberating the mass of the constituent particles minus the energy to separate them due to the binding energy. But my question is, why do they need to be separated? Can I not just annihilate them as they are?

According to this article: https://news.mit.edu/2019/quark-speed-proton-neutron-pairs-0220 the quarks slow down in Short-Range Correlated pairs as they have a larger volume to move in.

I was wondering if the pions/quarks have less momentum because of the increase in volume and this lower energy state is responsible for mass defect. Or a part of it?

Qmechanic
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TheJeran
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1 Answers1

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The term "mass defect" is useful for nuclear physics, where the constituent particles are neutrons and protons, which form quantum mechanically bound states.

For hadrons, which in current models are composed of quarks and a sea of quark antiquark and gluons there is no mainstream model where one could use the term "mass defect" because the force that binds hadrons in the strong nuclear force and Bohr type models of bound states cannot fit the data. Quantum chromodynamics is studied with lattice QCD.

The proton is also a hadron, and this is how one can image what is happening with the quarks and gluons and antiquarks composing it:

proton

Snapshot of a proton -- and imagine all of the quarks (up,down,and strange -- u,d,s), antiquarks (u,d,s with a bar on top), and gluons (g) zipping around near the speed of light, banging into each other, and appearing and disappearing. (M.Strassler 2010)

The paper you quote is studying a quantum mechanical effect in nuclei due to the number of protons and neutrons in nuclei, but this has little to do with the mass defect of the total nucleus, using the masses of protons and neutrons. Note that the EMC effect is seen in accelerator experiments, which is the only way to measure quark velocities from the high energy jets of particles observed.At most it could be a tiny correction to the measured mass defect.

anna v
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