在LEPⅡ及NLC能量下e~＋e~－→b_b~－Z^0和t_t~－Z^0过程中Higgs粒子的观测效应

On the Observation Effects of Higgs Particle in e￣+e￣-→ b_b￣-Z￣0和t_t￣-Z￣0 at LEP Ⅱ and NLC

根据最小标准模型及双Ｈｉｇｇｓ二重态的扩展标准模型理论，计算了ＬＥＰⅡ以及ＮＬＣ能量下ｅ＋ｅ－→ｂＺ０和ｔＺ０的总截面和微分截面以探求Ｈｉｇｇｓ粒子的观测效应．我们发现，只要Ｈｉｇｇｓ粒子的质量ＭＨ≤１４０ＧｅＶ，对ｅ＋ｅ－→ｂＺ０的测量就能清楚地提供Ｈｉｇｇｓ粒子的信息．然而对ｅ＋ｅ－→ｔＺ０，不论Ｈｉｇｇｓ粒子是轻或重，它的效应都被淹没在弱电过程的本底中，没有观测的可能．

According to the Minimal Standard Model and the Extended Standard Model with two Higgs doublets, we calculated the total cross sections and differential cross sections for the e+e-→bZ0 and tZ0 at the LEP Ⅱ and NLC energies in order tO study the possible observational effects of the Higgs particle. We found that the observation for the e+e-→ bZ0 can give the information on the Higgs particle as long as the mass of the Higgs particle MH≤140GeV. However, for the e+e-→tZ0 the effect from Higgs particle will be completely suppressed by the electrowead background and cannot be observed, no matter whether the Higgs particle is heavy or light.