The First Observation Of J/??K~-?(?~0)(?)+c.c. And Studies On Excited States Of Hyperon

The study of baryon is an important part for High-energy physics.Many excit-ed baryon states predicted by quark model are not found experimentally,among them about 30 states are(?)*s of double strangeness.Up to now,very limited experimental in-formation is known about the(?)*s except(?)(1530),(?)(1820).The J/? particle has been found in 1974,and J/? decays regarded as a promising place to study excited baryon s-tates.After upgraded the BESIII collected about(1310.6±7.0)× 106 J/? events.It is the largest J/? data sample in the world which provides a unique experimental condition for us to study charmonium decays and search for the excited baryon states.Based on these J/? data samples collected by BESIII,the decays of J/??K-?(?0)(?)+ + c.c.are observed and measured accurately,the branching ratios of these channels have been presented.The(?)(1690)observed in J/??K-?(?0)(?)+ + c.c.are measured,including mass,width and spin parity.As the phase space in these channels is quite small,and the momentum of the final particles is very low,a series of difficulties correlated had been solved by some unique methods,which not only suppressed the backgrounds,but also ensured the efficiency of event selection.The results,including statistic error and systematic error as below.branching ratios:The decays of J/??K-?(?0)(?)+ + c.c.are firstly observed and measured,the signals clear and the results of(?)(1690)are consistent with the value in PDG.