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A bestiary of exotic hadrons

(cerncourier.com)
152 points rbanffy | 3 comments | 20 Dec 24 15:29 UTC | HN request time: 0.419s | source
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whatshisface ◴[20 Dec 24 16:02 UTC] No.42472224[source]▶
>The dynamics of quarks and gluons can be described perturbatively in hard processes thanks to the smallness of the strong coupling constant at short distances, but the spectrum of stable hadrons is affected by non-perturbative effects and cannot be computed from the fundamental theory. Though lattice QCD attempts this by discretising space–time in a cubic lattice, the results are time consuming and limited in precision by computational power. Predictions rely on approximate analytical methods such as effective field theories.

I'm glad this was mentioned, non-perturbative effects are not well understood and this is a big part of why it's worthwhile to study bound states of the strong force.

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1. evanb ◴[20 Dec 24 20:31 UTC] No.42474738[source]▶
Give LQCD practitioners resources on the scale of the experiment, the computations will get faster!

I'm not sure what they mean by "Predictions rely on approximate analytical methods such as effective field theories." The predictions of LQCD are ab initio. Sometimes we fit EFTs to LQCD results, that's true. But EFTs are under control and have quantifiable uncertainties, they're not just willy-nilly approximations.

replies(2): >>42474847 #>>42475109 #
2. trentonstrong ◴[20 Dec 24 20:46 UTC] No.42474847[source]▶
May be referring not to LQCD relying on approximate analytical methods but some of the other non-perturbative methods? Example would be trying to apply homotopy analysis method (HAM) or a related transform to whatever field equations to make some semi-analytical predictions.
3. ◴[20 Dec 24 21:14 UTC] No.42475109[source]▶