Kination models predict the enhanced Hubble rate in the early universe.We investigate the relic density of Weakly Interacting Massive Particles(WIMPs) in the Kination models.We find an approximate analytic formula which can produce the relic particle abundance correctly.We demonstrate that our analytic formula gives the correct relic density
Kolb E W,Turner M S.The Early Universe[M].Redwood City,CA,Addison-Wesley,1990,115-156.
Bertone G,Hooper D,Silk J.Particle Dark Matter:Evidence,Candidates and Constraints[J].Phys Rep,2005,405:279-390.
Salati P.Quintessence and the Relic Density of Neutralinos[J].Phys Lett B,2003,571:121-131.
Scherrer R J,Turner M S.On the Relic,Cosmic Abundance of Stable Weakly Interacting Massive Particles[J].Phys Rev D,1986,33:1585- 1589,Erratum-ibid D,1986,34:3263-3263.
Griest K,Seckel D.Three exceptions in the calculation of relic abundances[J].Phys Rev D,1991,43:3191-3203.