Lifetime of Doubly Charmed Baryons

In this work,we evaluate the lifetimes of the doubly charmed baryons（?）;,（?）;,and Ω;.We carefullycalculate the non-spectator contributions at the quark level,where the Cabibbo-suppressed diagrams are also included.The hadronic matrix elements axe evaluated in the simple non-relativistic harmonic oscillator model.Our numericalresults are generally consistent with that obtained by other authors who used the diquaxk model.However,all thetheoretical predictions on the lifetimes are one order larger than the upper limit set by the recent SELEX measurement.This discrepancy would be claxified by the future experiment.If more accurate experiment still confirms the value of theSELEX collaboration,there must be some unknown mechanism to be explored.