Dispersive analysis of low energyγN→πN process and studies on the N^*(890)resonance

作     者：Yao Ma Wen-Qi Niu De-Liang Yao Han-Qing Zheng 马垚;牛文奇;姚德良;郑汉青

作者机构：Department of Physics and State Key Laboratory of Nuclear Physics and TechnologyPeking UniversityBeijing 100871China School of Physics and ElectronicsHunan UniversityChangsha 410082China Collaborative Innovation Center of Quantum MatterBeijing 100871China 

出 版 物：《Chinese Physics C》 (中国物理C（英文版）)

年 卷 期：2021年第45卷第1期

页      面：252-264页

核心收录：

学科分类：0709[理学-地质学] 08[工学] 0708[理学-地球物理学] 0804[工学-仪器科学与技术] 0827[工学-核科学与技术] 082701[工学-核能科学与工程] 0703[理学-化学] 0704[理学-天文学] 0702[理学-物理学] 

基　　金：Supported by National Nature Science Foundations of China(NSFC)(11905258,11975028,10925522) by the Fundamental Research Funds for the Central Universities(531118010379) 

主　　题：dispersive representation nucleon resonance pion photoproduction off the nucleon 

摘      要：We present a dispersive representation of the γN→πN partial-wave amplitude based on unitarity and *** this representation,the right-hand-cut contribution responsible for πN final-state-interaction effects is taken into account via an Omnes formalism with elastic πN phase shifts as inputs,while the left-hand-cut contribution is estimated by invoking chiral perturbation *** fits are performed to pin down the involved subtraction *** fit quality can be achieved with only one free parameter,and the experimental data regarding the multipole amplitude E0+ in the energy region below the △(1232) are well ***,we extend the γN →μN partial-wave amplitude to the second Riemann sheet to extract the couplings of the N*(890).The modulus of the residue of the multipole amplitude E0+(S11pE) is 2.41 mfm·GeV2,and the partial width of N*(890)→ yN at the pole is approximately 0.369 MeV,which is almost the same as that of the N*(1535) resonance,indicating that N*(890) strongly couples to the πN system.