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Symmetry between up and down quarks is more broken than expected

(phys.org)
87 points terminalbraid | 1 comments | 29 Mar 25 10:12 UTC | HN request time: 0.208s | source
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ptsneves ◴[31 Mar 25 15:17 UTC] No.43536027[source]▶
What are the consequences for this breakage? The article says current models do not easily fit the asymmetry but does not state what parts of our understanding will break if those models are wrong.
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fpoling ◴[31 Mar 25 15:31 UTC] No.43536209[source]▶
Strong interactions are notoriously difficult to calculate from the first principles. So typically it is not done, but rather theoreticians try to guess the result and use the experimental data to partially fill the calculation gaps.

So I expect in this cases the guesses were wrong and the Standard Model will manage to explain that as well.

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facile3232 ◴[31 Mar 25 22:23 UTC] No.43540611[source]▶
> Strong interactions are notoriously difficult to calculate from the first principles.

??? Where does empiricism come in? Surely you need some kind of data to feed even raw assumptions. Maybe I'm just misinterpreting how "first principles" is employed here.

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1. fpoling ◴[31 Mar 25 23:58 UTC] No.43541359[source]▶
The first principles here refer to the basic equations of the Standard Model. There were a lot of alternative theories in sixties and seventies but eventually they were disproven experimentally and only SM survived.

But the problem with SM is that when one deals with strong interactions, nobody so far came with good ways to calculate things. For example, in theory the mass of proton can be derived. But in practice it is not. So one uses that as an extra parameter and tries to use that to constrain calculations in other areas.