Studies of the J/Ψ → anti-Σ0Σ0 Reaction with BESIII : Event Selection Development

Abstract: The apparent symmetry between matter and antimatter raises the question of why the universe consists of mostly matter. Via an academic exchange to USTC Hefei, a reaction was studied that aims to give insight into this question. Through their electromagnetic decay, Σ0 hyperons provide an exciting opportunity to search for physics beyond the Standard Model of particle physics, and try to answer the question of matter-antimatter asymmetry in the universe. Over 1010 data events have been detected at the BESIII-experiment in Beijing. This project develops an event selection algorithm to select J/Ψ → anti-Σ0Σ0 events from background. This project uses a secondary vertex fit and a kinematic fit, as well as mass cuts, to filter out signal events with an efficiency of 15% at a background level of under 0.5%. The results are verified using signal Monte-Carlo data, and simulated background. Cut parameters have been optimized by tracking which reactions pass selection. Experimental data showed no significant difference to simulations. The method shows promise for precision studies of J/Ψ → anti-Σ0Σ0.