Timeline for Where is the proton mass coming from?
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
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| May 18, 2018 at 3:45 | vote | accept | Juanjo | ||
| May 11, 2018 at 15:33 | comment | added | dmckee --- ex-moderator kitten | @Sean The resolution of the difficulty that Roger discusses is "asymptotic freedom": the observation that as you increase interaction energies, the kinematics of hadronic final states become increasingly similar to those expected if the quarks were free, and because increasing energy implies shorter distance we assign the zero of strong interaction energy to zero separation instead of infinite separation as with other forces. But the system is still bound which means energy grows with separation so the potential energy must be positive. | |
| May 11, 2018 at 9:08 | comment | added | RogerJBarlow | This is more subtle than it appears. Because of confinement, there is no such thing as a 'separated quark'. We can only consider quarks in mesons or baryons or the QGP, where their behaviour depends on the colour-force field they're experiencing. That's why the 'mass of the quark' is not a generally defined concept and the tables of properties always show masses as 'of the order of', especially for light quarks. The analogy with nuclear masses (where there are no problems with considering free protons and free neutrons) is not helpful. | |
| May 11, 2018 at 8:19 | comment | added | Sean E. Lake | @dmckee This doesn't even make sense to me "negative binding energies," because it only makes sense to refer to negative interaction energies as binding energies. Do you mean positive interaction energies (i.e. a repulsive interaction)? | |
| May 11, 2018 at 5:17 | comment | added | dmckee --- ex-moderator kitten | @SeanE.Lake The nuclear force (AKA residual strong force) has negative binding energies. The underlying strong force has positive binding energies—part and parcel of confinement. | |
| May 11, 2018 at 5:06 | vote | accept | Juanjo | ||
| May 11, 2018 at 5:07 | |||||
| May 11, 2018 at 4:40 | answer | added | anna v | timeline score: 3 | |
| May 11, 2018 at 4:34 | history | edited | Qmechanic♦ |
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| May 11, 2018 at 3:47 | answer | added | user4552 | timeline score: 1 | |
| May 11, 2018 at 3:40 | comment | added | Sean E. Lake | "plus their binding energies" That should be minus. 2 protons and 2 neutrons weigh more than a Helium-4 nucleus, for example. | |
| May 11, 2018 at 3:36 | history | asked | Juanjo | CC BY-SA 4.0 |