Photoproductionγp→K^(+)Λ(1690)in an effective Lagrangian approach  

作　　者：Neng-Chang Wei Ai-Chao Wang Fei Huang 韦能昌;王爱超;黄飞(School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 101408,China

出　　处：《Chinese Physics C》2022年第5期44-51,共8页中国物理C（英文版）

基　　金：Partially supported by the National Natural Science Foundation of China(12175240,11475181,11635009);the Fundamental Research Funds for the Central Universities,the China Postdoctoral Science Foundation(2021M693141,2021M693142);the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(Y7292610K1)。

摘　　要：A gauge-invariant model is constructed for theγp→K^(+)Λ(1690)reaction within a tree-level effective Lagrangian approach to understand the underlying production mechanisms and study the resonance contributions in this reaction.In addition to the t-channel K and K^(∗)exchanges,s-channel nucleon exchange,and interaction current,the s-channel nucleon resonance exchanges are included in constructing the reaction amplitudes to describe the data.It is found that the contributions from the s-channel N(2570)5/2^(−)exchange are required to describe the most recently measured total cross-section data forγp→K^(+)Λ(1690)from the CLAS Collaboration.Further analysis indicates that the interaction current dominates the γ p→K^(+)Λ(1690)reaction near the threshold as a result of gauge invariance.The t-channel K exchange contributes significantly,while the contributions from the t-channel K^(∗)exchange and s-channel nucleon exchange are ultimately negligible.The contributions from the s-channel N(2570)5/2^(−)exchange are found to be responsible for the bump structure shown in the CLAS total cross-section data above the center-of-mass energy W≈2.7 GeV.The predictions of the differential cross sections forγp→K^(+)Λ(1690)are presented and discussed,which can provide theoretical guidance for future experiments.

关 键 词：K^(+)Λ(1690)photoproduction effective Lagrangian approach gauge invariance 

分 类 号：O571[理学—粒子物理与原子核物理]