光生反应γp→π-Δ++中的核子激发态

doi:10.7523/j.ucas.2021.0042

中国科学院大学学报 ›› 2024, Vol. 41 ›› Issue (1): 35-41.DOI: 10.7523/j.ucas.2021.0042

光生反应γp→π^-Δ⁺⁺中的核子激发态

朱一鸣, 杨富中

中国科学院大学物理科学学院, 北京 100049

收稿日期:2021-04-19 修回日期:2021-05-11 发布日期:2024-01-13
通讯作者: 杨富中，E-mail:fzyang@ucas.ac.cn
基金资助:
国家自然科学基金(11475178)资助

Nucleon resonances in γp→π^-Δ⁺⁺ photoproduction

ZHU Yiming, YANG Fuzhong

School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

Received:2021-04-19 Revised:2021-05-11 Published:2024-01-13

摘要/Abstract

摘要： 运用有效拉氏量方法分析LEPS合作组首次发布的关于γp → π^-Δ⁺⁺反应的高精度微分截面和极化观测量Beam asymmetry(Σ)的实验数据。把t道的π和ρ交换，u道的Δ交换，s道的核子N交换以及使光生反应振幅满足规范不变性的推广接触项作为背景项，尝试在s道进一步引入核子激发态交换的贡献以描述此实验数据。分析表明，如果在模型计算中不引入s道核子激发态交换的贡献，背景项的理论计算结果虽然能够大体上描述γp→π^-Δ⁺⁺反应的微分截面的实验数据，但是无法描述极化观测量Σ的实验数据；在s道中引入核子激发态N(1860)5/2⁺，模型计算结果就能够很好地同时描述LEPS实验组的微分截面和极化观测量Σ的实验数据。

关键词: 光生反应, 核子激发态, 有效拉氏量方法

Abstract: The first measured high-precision data on the differential cross sections and polarization observable beam asymmetry Σ for the γp→π^-Δ⁺⁺ reaction from the LEPS collaboration are analyzed within a tree-level effective lagrangian approach. In addition to the t-channel π and ρ exchanges, the u-channel Δ exchange, the s-channel N exchange, and the interaction current that is required by the gauge invariance, the s-channel nucleon resonance exchanges are further taken into account to reproduce the data of LEPS. Numerical results show that, the data on Σ can not be well reproduced when no contributions from the s-channel resonance exchanges are introduced. Further analyses show that, by including the contribution from the resonance N(1860)5/2⁺, both the data on the differential cross sections and beam asymmetry Σ can be well reproduced.

Key words: photoproduction reaction, nucleon resonances, effective lagrangian approach

中图分类号:

O572.33

朱一鸣, 杨富中. 光生反应γp→π^-Δ⁺⁺中的核子激发态[J]. 中国科学院大学学报, 2024, 41(1): 35-41.

ZHU Yiming, YANG Fuzhong. Nucleon resonances in γp→π^-Δ⁺⁺ photoproduction[J]. Journal of University of Chinese Academy of Sciences, 2024, 41(1): 35-41.

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光生反应γp→π^-Δ⁺⁺中的核子激发态

Nucleon resonances in γp→π^-Δ⁺⁺ photoproduction

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光生反应γp→π-Δ++中的核子激发态

Nucleon resonances in γp→π-Δ++ photoproduction

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光生反应γp→π^-Δ⁺⁺中的核子激发态

Nucleon resonances in γp→π^-Δ⁺⁺ photoproduction