Double heavy diquark--anti-quark symmetry: The little symmetry that might
U. of Maryland
In the limit of heavy quark masses going to infinity, asymmetry is known to emerge in QCD relating properties of hadrons with two heavy quarks to analogous states with one heavy anti-quark. A key question is whether the charm mass is heavy enough so that this symmetry is manifest in at least an approximate manner. This issue is crucial in attempting to understand the recent reports by the SELEX collaboration of double charmed baryons. This talk will discuss the expectations of the hadronic spectrum in the heavy quark limit, and compare this with the experimental results. It will be argued that the charm quark mass is substantially too light for the symmetry to emerge automatically, as in the heavy quark limit. However, the symmetry could emerge approximately depending of the dynamical details of non-peturbative physics.