11 ms·

Does this help as a starting point? http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/scatele.html#c1 http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/scate

Does this help as a starting point? http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/scatele.html#c1 http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/scatele.h...

cperciva 8y ago
Yes, I think that answers my question -- if I'm reading it right, the scattering behaviour of low-energy electrons indicates that they're hitting something "proton-like" rather than something "quark-like" inside the nucleus?
- ahazred8ta 8y ago
  Yes, exactly. At low energies we can see that most of the atom's mass is in a nucleus. At medium energies we see that there are proton and neutron sized lumps in the nucleus. At very high energies we can see that the protons etc have quark sized lumps inside them. (Full disclosure: FWIW I took a physics course from one of the professors on the team which discovered gluons.)
- raattgift 8y ago
  Yes. Nucleons and quarks represent internal degrees of freedom (DoFs) inside the nucleus resp. proton that can receive momentum-energy from a scattering electron. This is measured as a loss of the sum of the kinetic energies of the electron and its target. At low energies, the transfer to internal DoFs is negligible, so the scattering is elastic. At higher energies the transfer is relatively large, so the scattering is inelastic. At sufficiently high energy, the nucleus disintegrates into components and new particles, and in the target's centre-of-momentum frame the sum of all their kinetic energies matches the change of the electron's. But at even higher energy there is again an apparent loss of kinetic energy, so there must be further internal DoFs within the components. Those are in the proton. The higher energy scatterings are "deep". As one does deep inelastic scattering, the proton's internal DoFs absorb electron momentum-energy. At sufficiently high energy levels the proton disintegrates into many new particles. There are also differences in the scattering angle -- the amount by which the scattered electron is deflected from its beam path. Scattering angles are low in elastic scattering, and high in inelastic scattering. This gives further information about the internal DoFs. For more see Mott scattering, deep inelastic scattering, and the parton model.

Does this help as a starting point? http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/scatele.html#c1 http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/scatele.h...

cperciva 8y ago

Yes, I think that answers my question -- if I'm reading it right, the scattering behaviour of low-energy electrons indicates that they're hitting something "proton-like" rather than something "quark-like" inside the nucleus?

ahazred8ta 8y ago
Yes, exactly. At low energies we can see that most of the atom's mass is in a nucleus. At medium energies we see that there are proton and neutron sized lumps in the nucleus. At very high energies we can see that the protons etc have quark sized lumps inside them. (Full disclosure: FWIW I took a physics course from one of the professors on the team which discovered gluons.)
raattgift 8y ago
Yes. Nucleons and quarks represent internal degrees of freedom (DoFs) inside the nucleus resp. proton that can receive momentum-energy from a scattering electron. This is measured as a loss of the sum of the kinetic energies of the electron and its target. At low energies, the transfer to internal DoFs is negligible, so the scattering is elastic. At higher energies the transfer is relatively large, so the scattering is inelastic. At sufficiently high energy, the nucleus disintegrates into components and new particles, and in the target's centre-of-momentum frame the sum of all their kinetic energies matches the change of the electron's. But at even higher energy there is again an apparent loss of kinetic energy, so there must be further internal DoFs within the components. Those are in the proton. The higher energy scatterings are "deep". As one does deep inelastic scattering, the proton's internal DoFs absorb electron momentum-energy. At sufficiently high energy levels the proton disintegrates into many new particles. There are also differences in the scattering angle -- the amount by which the scattered electron is deflected from its beam path. Scattering angles are low in elastic scattering, and high in inelastic scattering. This gives further information about the internal DoFs. For more see Mott scattering, deep inelastic scattering, and the parton model.