Ruhr-Universität Bochum

Project leader: Prof. Dr. Alfons Khoukaz

In the scope of the research project suggested here, available and future data gathered with the BESIII experiment shall be used for a systematic investigation in the search for exotic particles and the study of their properties. For the proposed work, extensive datasets stemming from e⁺e^– collisions exist, which will be enlarged at the BEPCII storage ring with direct participation of our working group. At the center of our interest are the high energy data between √s=3.70 GeV and √s=4.60 GeV, which had recently been used to extract valuable information regarding the exotic particle candidates Y(4260) and Y(4360) using their decay to the J∕ψπ⁺π^– final state. The main objective of the research project suggested here is the investigation of reactions with a proton-antiproton pair in the final state. In more detail, the channels e⁺e^– → pp, e⁺e^– → ppγ, e⁺e^– → ppω, e⁺e^– → ppη, e⁺e^–→ ppϕ and e⁺e^–→ ppππ shall be studied. Here, it is possible to detect these reactions both directly as well as in initial state radiation processes, e.g., in e⁺e^–→γ_ISRppX. Data collected with the BESIII experiment will allow to search for possible resonances in the quoted energy region. In addition, the search for resonances in the pp subsystem is of high interest with regard to the future PANDA experiment, in which proton-antiproton collisions will be used for direct searches of exotic particles in the charmonium sector. As a member of the PANDA collaboration, a close cooperation between both collaborations will be facilitated.

Additionally, the production of the possibly exotic state X(3915) shall be studied in the reaction e⁺e^–→ X(3915)ππ, with the X(3915) decaying into the prominently seen J∕ψω channel. Using a partial wave analysis, the currently ambiguous spin-parity assignment of the X(3915) state as either J^PC = 0⁺⁺ or J^PC = 2⁺⁺ can potentially be resolved.