Recent results from the jade collaboration* at petra on e+e− annihilation to multihadrons

A search for production of a new quark flavor in multihadronic states from e+e− annihilation has been made up to an energy of 35.8 GeV in the center of mass. No evidence is seen for such production. A new statistical analysis by the JADE collaboration of the combined data of four PETRA experiments from a fine energy scan in the region 29.90 to 31.46 GeV in the center of mass sets new upper limits on the integrated cross section for a bound state consisting of a new flavor quark and antiquark. The ability of the JADE detector to measure dE/dx provides new upper bounds on the production of fractionally charged particles such as free quarks, or of heavy, integrally charged states such as long‐lived B mesons. Finally the fractions of the final state energy carried by gamma rays and by neutral particles of all kinds are measured at center of mass energies from 12 to 35 GeV. The gamma ray and neutral energy fractions are approximately 26% and 38% respectively, while the fractional energy carried by neutrinos is less than 15%.