Anomalous line shape of the cross section for e{+}e{-}--> hadrons in the center-of-mass energy region between 3.650 and 3.872 GeV

Phys Rev Lett. 2008 Sep 5;101(10):102004. doi: 10.1103/PhysRevLett.101.102004. Epub 2008 Sep 5.

Abstract

We observe an obvious anomalous line shape of the e;{+}e;{-}--> hadrons total cross sections in the energy region between 3.700 and 3.872 GeV. It is inconsistent with the explanation for only one simple psi(3770) resonance with a statistical significance of 7sigma. The anomalous line shape may be explained by two possible enhancements of the inclusive hadron production near the center-of-mass energies of 3.764 and 3.779 GeV, indicating that either there is likely a new structure in addition to the psi(3770) resonance around 3.773 GeV, or there are some physics effects reflecting the DD[over ] production dynamics.