Study on the Energy Dependence of the Source Size of Jets by the HBT Correlation Method in $e^+e^-$ Collisions
Chen Zheng-Yu (Physics Department, School of Mathematics and Physics, China University of Geosciences, 430074 Wuhan, China); Chen Gang (Physics Department, School of Mathematics and Physics, China University of Geosciences, 430074 Wuhan, China); Wang Mei-Juan (Physics Department, School of Mathematics and Physics, China University of Geosciences, 430074 Wuhan, China); Xie Yi-Long (Physics Department, School of Mathematics and Physics, China University of Geosciences, 430074 Wuhan, China); Liang Zhu (Physics Department, School of Mathematics and Physics, China University of Geosciences, 430074 Wuhan, China)
The energy dependence of the source size of jets are studied in detail by the HBT correlation method using Monte Carlo Simulation generator {\sf Jetset7.4} to produce 40,000,000 events of $e^+e^-$ collisions at $\sqrt s = 30$, 50, 70, 91.2, 110, 130, 150 and 170~GeV, respectively. The source size of jets are measured using the HBT correlation method with the indistinguishability of identical final state pions. The average source radii of quark-jets and gluon-jets in $e^+e^-$ collisions are obtained at the end of parton evolvement. It is found that the average source radii of quark-jets are obviously larger than those of gluon-jets and the average source radii measured with $\pi^0$ meson are smaller than those with $\pi^+$ or $\pi^-$ meson.
