报告时间地点：10月22日(周四)下午3：30，理六二楼多功能厅

Title:  Pion-Nucleon Scattering within Covariant Baryon Chiral
Perturbation Theory

Abstract:

Pion-nucleon scattering is an important process for the understanding
of chiral QCD dynamics and strong interactions. In this talk, I will
show our result of the analytic and complete pion-nucleon scattering
amplitudes up to O(p^4), and regularize it in the
extended-on-mass-shell scheme which faithfully respects analyticity.

Numerical fits to partial wave phase shift data are performed to pin
down the free low energy constants, and a good convergence for the
chiral series at O(p^4) is achieved. Based on the amplitudes, a
phenomenological discussion is made on the pion-nucleon sigma term,
which is the main source of uncertainty in the interpretation of
direct searches of supersymmetric dark matter.

个人简介：

陈云华，2012年7月北京大学理论物理专业博士毕业。2012.7-2015.2，中科院高能物理研究所理论物理室博士后。

2015.2至今，德国波恩大学博士后。研究方向主要是用手征有效理论和色散关系研究粒子物理中的强子物理和核物理，其中在pi-N散射，通过光生过程研究重子谱，介子的电磁衰变和形状因子等方面发表Phys.Rev.D 和 Phys.Rev.C
文章若干篇。