Multiquark Correlations in Light Mesons and Baryons from holographic QCD

摘要

A hadron's multiquark content reflects itself in the quark composition of the interpolator with which it has maximal overlap. The AdS∕CFT dictionary translates the anomalous dimension of this interpolator into a mass correction for the corresponding dual mode. Hence such bulk‐mass corrections can carry specific information on multiquark correlations. Two prominent examples are studied by implementing this robust and universal holographic mechanism into AdS∕QCD gravity duals. In the baryon sector bulk‐mass corrections are used to describe systematic good (i.e. maximally attractive) diquark effects. The baryon sizes are predicted to decrease with increasing good‐diquark content, and the masses of all 48 observed light‐quark baryon states are reproduced with unprecedented accuracy. Our approach further provides the first holographic description of a dominant tetraquark component in the lowest‐lying scalar mesons. The tetraquark ground state emerges naturally as the lightest scalar nonet whereas higher excitations become heavier than their quark-antiquark counterparts and are thus likely to dissolve into the multiparticle continuum.