e+e-湮没中轻夸克碎裂为粲介子的研究

研究了e+e-湮没中"初始"轻夸克和胶子劈裂产生的组合为介子(包括D-, D-s, 0)或*介子(包括D*-, D*-s, *0)的过程.发现尤其在s=MZ处,其产额相对较大,当限制或*的能量大于20GeV时,它和c夸克碎裂产物的不变质量谱在稍大于2M附近有一个峰,这是该过程区别于其它或*介子产生过程的显著特征.此过程产生的矢量介子基本上是纵向极化的,与实验上观测到的*介子的纵向极化一致.

Fragmentation of Light Initial Quarks into Charm Measons in e+e- Annihilation

We study the process that the light initial quarks produced in e+ e- annihilation combine with the c from glu-on splitting to form D's (D-+D6-+D0) or D 's(D-*+ Ds*-+D*0). The 'light + heavy' bound state is described by light-cone wavefunction. The contribution of this process to D (D ) production at Z0 pole is much larger compared with that in lower energies (e.g. 10.6GeV) . For this special process, the invariant mass of D(D ) and the charm had-ron fragmented from the c quark has a unique spectrum which peaks near 2 MB if we constrain the D(D*) from all processes with energy larger than 20GeV. It is also noticeable that the produced D* in this process is dominantly longitudinally polarized, which is consistent with the OPAL data.