关于不稳定强子衰变性质的研究

Some unstable hadrons (resonances) mainly decay into two final states in a very short time. This paper estimates how far at most these two final states can travel away from each other in the half-life of the initial unstable hadron. As examples, this distance is about 2.5 fm for $ ho ightarrow pi pi$, 1.8 fm for $Delta ightarrow N pi$, and 0.6 fm for $f_0(500) ightarrow pi pi$. This paper calculates this distance for altogether 181 hadrons, among all the 324 ones listed in PDG2012. It is around one femtometer for many hadrons, which is of the same order of magnitude as the hadronic radii. This paper also estimates this distance for altogether 15 unstable nuclei. It is about several femtometers for some of them, which is of the same order of magnitude as the nuclear radii.