精品文档---下载后可任意编辑BESⅢ 上粲偶素到赝标量介子对衰变的讨论的开题报告Title: Study of ηc → pseudoscalar meson pairs decays at BESIIIIntroduction:The ηc meson is a unique particle in the charmonium family due to its JPC quantum numbers being 0-. Studying the decay of ηc to pseudoscalar meson pairs (PP) is important for understanding the nature of non-perturbative QCD. Previous measurements have found that the ηc→π+π-, ηπ+π-, κ+K-, and κ+K*0 decays are suppressed relative to expectations from naive perturbative QCD, indicating the importance of non-perturbative effects. BESIII is a perfect detector to study the non-perturbative effects in ηc → PP decays.Objectives:The main objectives of this study are:1. To measure the branching fractions of the ηc → PP decay channels2. To investigate patterns in the non-perturbative behavior of these decays3. To test the predictions of different theoretical models for these decay channelsMethodology:The ηc mesons will be produced through e+e- annihilation at a center-of-mass energy of 3.773 GeV, which is the peak of the cross-section for the production of charmonium states. The BESIII detector will be used to reconstruct the PP decay products and measure the branching fraction. The non-perturbative effects will be studied by comparing the branching fractions with theoretical predictions from perturbative QCD and other non-perturbative models.Expected Outcomes:We expect to measure the branching fractions for the following decay channels:精品文档---下载后可任意编辑1. ηc → π+π-2. ηc → ηπ+π-3. ηc → K+K-4. ηc → K+K*0We also expect to find evidence for non-perturbative effects in these decays and to test the predictions of different theoretical models. Our study will contribute to the understanding of non-perturbative QCD and shed light on the nature of the ηc meson.
