分别从类空和类时两方面利用电磁探针去研究强子体系，能给出对强子性质更为全面地认识。目前BES， Belle, Babar等e+e-对撞实验装置都观测到大量的末态正反强子对[B\bar{B}] 或者强子的产生过程，如e+e--->pi+pi，rho+rho, N\bar{N},\Lambda\bar{\Lambda} 以及[X+氘核] 等。这些过程能给出非常丰富的强子内部结构的信息。对它们的研究，会从类时角度，加深认识强子内部性质，比如加深理解介子，核子，核子激发态、轻核，奇特强子态等的形状因子的类时行为；深入认识体系内部夸克-胶子的分布，或广义分布振幅（Generalized Distribution Aamplitudes ）。另外，还会对理解通过强子对产生出来的奇特强子态的性质有帮助。本课题与以往大量从类空角度出发的研究课题相互补充， 同时也会对相应物理实验现象的理解有帮助。

By using the electromagnetic probes both in space-like and in time-like regions, an entire description for hadrons can be obtained. So far BES, Belle, Babar and other facilities with e+e-annihilation processes can observe many hadron pair [B\bar{B}] or hadron productions, like e+e--->pi+pi，rho+rho, N\bar{N}, \Lambda\bar{\Lambda}, and [X+deuteron] et al..Those processes can give very rich information about the internal structures of hadrons, particularly in time-like region. For example, the time-like form factors (or transition form factors) of mesons, nucleons, nucleon excitations, light nuclei, and exotic states. Moreover, they also give the generalized distribution amplitudes (GDAs), which are the time-like representation of the generalized parton distributions (GPDs), telling the three-dimensional quark-gluon distributions inside the systems. In addition, one can also get information about the structures of some exotic states in the production processes. It should be stressed that this project is complementary to many other studies, in the literature, in the space-like region, and is helpful for the understaning of experiemtal measurents.