夸克模型认为强子由一对正反夸克或三个正（反）夸克组成，然而量子色动力学允许强子以胶球、混杂态、多夸克态等“新型强子”组成方式。实验寻找和研究新型强子，对深入了解强子组成、检验和发展低能区量子色动力学具有重要意义。pi_1(1600)发现于上世纪80年代，是最重要的1-+混杂态候选者。迄今pi_1(1600)只在piN散射和ppbar湮灭过程中被观测到，仅有一例报道在chi_c1的强衰变过程中观测到可能存在的迹象，因统计量限制无法给出确定结论。BESIII实验采集了世界上最大的psi'衰变样本，前期研究中我们使用该样本在chi_c1->eta'pi+pi-过程中观测到pi1_(1600)粒子存在，显著性超过7sigma。我们计划使用BESIII的chi_c1衰变数据，测量pi_1(1600)质量、宽度及衰变分支比，寻找pi_1(1600)的其它衰变模式，以及寻找其它的1-+奇特态。

In quark model, hadrons consist of a pair of quark-antiquark or three quarks (antiquarks). However, the QCD theory of strong interaction allows existence of the so called new types of hadron such as glueball, hybrid, multiquark state etc. Search for and research of new types of hadron is essential for understanding how hadrons form, examining and developing the QCD theory in low energy region. The pi_1(1600), being a 1-+ exotic state, has been considered as a hybrid candidate for a long time. Up to now, pi_1(1600) was only observed in piN scattering and ppbar annihilation. Only one reported evidence of pi_1(1600) in chi_c1 decays, but no solid conclusion was made due to limited statistics. BESIII experiment has collected the world largest psi' decay sample (hence the largest chi_c1 decay sample), providing a perfect place for search for pi_1(1600) and other 1-+ exotic states in chi_c1 decays. In early studies, we have already observed the pi_1(1600) in chi_c1->eta' pi+ pi- with 7sigma significance. With BESIII's data sample, we plan to 1) measure pi_1(1600)'s mass, width, branching ratio, and 2) search for pi_1(1600) in its other decay modes, and 3) search for other 1-+ exotic states.