Large next-to-leading-order QCD corrections to pentaquark sum rules

Using configuration space techniques, we calculate next-to-leading order (NLO) five-loop QCD corrections to the correlators of interpolating pentaquark currents in the limit of massless quarks. We obtain very large NLO corrections to the spectral density which makes a standard sum rule analysis problematic. However, the NLO corrections to the correlator in configuration space are reasonable. We discuss the implications of our results for the phenomenological sum rule analysis of pentaquark states.

Figure 1

LO contribution (a) and examples for the NLO propagator (b) and dipropagator corrections (c).