EVIDENCE FOR A NARROW RESONANCE AT 10.01 GeV IN ELECTRON-POSITRON ANNIHILATIONS

The observation of the T meson [1,2] as a narrow resonance in e l ec t ron-pos i t ron annihilations in the DORIS storage ring indicates that the T is a bound jPC = 1 state of a new quark and its antiquark. If this interpretat ion is correct, there should be narrow excited states of the T, in analogy with the J / ¢ family. The FNAL experiment [3], which originally discovered the q" in p ro ton-nuc leus interactions, found evidence for further peaks in the mass spectrum at 10.0 ( T ' ) and 10.4 ( T " ) GeV. As the T, T ' and T " are generally interpreted as 1S, 2S and 3S states, the determinat ion of their exact mass is of great importance: once the level spacing between the different T states and their decay widths are known, the shape of the q u a r k q u a r k interaction potential Can be determined with high accuracy [4,5].