【摘要】 大统一理论（GUT）预言了超重磁单极存在。如果磁单极是二级（或弱一级）相变产生的。那么在宇宙早期核子合成时代,磁单极密度的估计值将远大于观察值的上限。本文提出一类新的大统一模型,它以SU_L（2）×U₁（1）×…×U_n（1）为弱电规范群。由于其中必定存在Z弦相互作用,因而它所预言的宇宙早期磁单极与标准热大爆炸宇宙学预言的没有矛盾。更多还原

【Abstract】 Grand Unified Theories predict the existence of superheavy magnetic monopoles.Under the assumption that if the transition during which monopoles are created is second order（or weakly first order）,the monople number density at the time of nucleosynthesis has been estimated to be unacceptablly large. A SU_L（2）×U₁（1）×…×U_n（1）electroweak gauge group is studied in a framework of the unified scheme and the problem of magnetic monopoles conflicting with the standard Big Bang cosmology is naturally avoided,更多还原