Tuesday, March 19, 2019

Progress In Estimating Hadron Masses

The scalar and axial-vector meson results are particularly an improvement over past work. Top quarks, of course, do not hadronize, so five valence quark types is appropriate. It is also worth noting that the fundamental parameters of QCD are only known to about 0.5% to 1% significance (or worse), so given the multiple parameters at issue, the 2.4%-2.9% errors are not much different from doing first principles calculations using these fundamental parameters.
Using a confining, symmetry-preserving regularisation of a vector×vector contact interaction, we compute the spectra of ground-state pseudoscalar and vector (fg¯) mesons, scalar and axial-vector (fg) diquarks, and JP=1/2+,3/2+ (fgh) baryons, where f,g,h{u,d,s,c,b}. The diquark correlations are essentially dynamical and play a key role in formulating and solving the three-valence-quark baryon problems. The baryon spectrum obtained from this largely-algebraic approach reproduces the 22 known experimental masses with an accuracy of 2.9(2.4)   %. It also possesses the richness of states typical of constituent-quark models, predicting many heavy-quark baryons not yet observed. This study indicates that diquark correlations are an important component of all baryons; and owing to the dynamical character of the diquarks, it is typically the lightest allowed diquark correlation which defines the most important component of a baryon's Faddeev amplitude.
Pei-Lin Yin, Chen Chen, Gastao Krein, Craig D. Roberts, Jorge Segovia, Shu-Sheng Xu "Masses of ground-state mesons and baryons, including those with heavy quarks" (March 1, 2019).

Details results appear below the fold.

META NOTE: This is the 1600th post at this blog. 

The inputs used in the calculations are as follows:

Meson predictions:

Predictions and experiment compared for mesons:

Diquark predictions:

Prediction and experiment compared for diquarks:

Spin 1/2 baryon predictions:
Prediction and experiment compared for spin 1/2 baryons:
Spin 3/2 baryon predictions:

Prediction and experiment compared for spin 3/2 baryons:

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