Study Of ?(3686) Decaying Into ?~-(?)~- Baryonic Pair

This paper is based on the 4.48×108 samples of ?(3686)of BES? detector on the years of 2009 and 2012,which cms energy is 3.686GeV,and study of the processes of baryonic pair decay.On the processes of decay,we use the single tag method which is to reconstruct baryonic ?-(?+)on the process of ?(3686)??-?+,and research on decay of ?(3686)baryonic pair through full reconstruct method to reconstruct the state of the process of decay.Single tag method could improve of the selection efficiency of events and statistics of signal,and could reduce system errors and Statistical error.The measurement's result of The decay branching ratio on the process are as follows:the result of single tag method is(5.4±0.23±0.59)×10-5(marking ?+)and Br =(4.9±0.19±0.59)×105(marking ?+).The result of full reconstruct method is(5.11±0.43±1.25)×10-5,the first item is Center value,the second item is Statistical error,and the third item is System error.My paper has measured the distribution coefficient of cos? in?(3686)??-?+ process,the measurement results show that,there are some differences between marking ?-angular distribution coefficient and marking ?+ angular distribution under the same data samples,and these need further research.the sources of the systematic errors for the branching ratio measurements are analyzed,which include the uncertainties in the total number of the ?(3686)events;charged particle identify;branching fractions quoted from PDG;fitting;vertex and secondary vertex fitting;angular distribution coefficient ?,etc.