The Research On Relic Density Of Asymmetric Dark Matter In Non-standard Cosmology

The existence of dark matter is one of the most important discoveries in the field of particle cosmology.And supported by a series of astronomical observations.It is shown that the dark matter dominates in our universe and the ordinary baryon matter only gives a small contribution.The study of dark matter in the universe has become a hot spot in astrophysics,particle physics and Cosmology.among them The observation of the cold dark matter has become one of the hottest research fields nowadays.The most popular candidate for dark matter is the weakly interacting massive particles(WIMPs)which are assumed in the supersymmetric model.In our work we have focus on The non-standard cosmological scenarios consid-ered higher dimensional universe models(braneworlds).the relic density of symmetric dark matter particles(where particleχ and antiparticle-χare identical and therefore self-annihilating)and asymmetric dark matter particles(where particleχ and antiparticle-χare not self-conjugateχ≠χ)is calculated in several non-standard cosmological scenar-ios(scalar-tensor cosmology and quintessence)that predict a modified Hubble expansion rate in the pre BBN era.In terms of the dark matter particle interactions,we adopt a model independent approach and choose a generic form for the annihilation cross section(σv = a + 6bT/mχ(where T is the temperature of the universe and mχ is the dark matter particle mass),calculating results for both the S-(b = 0)and P-(α = 0)wave annihilation cases.Furthermore,Knowing the present dark matter density ΩDMh2 = 0.1138 ± 0.0045 is a precisely measured quantity,the relic abundance calculations are inverted to deter-mine the annihilation cross section<σv>,required to provide the observed density.In this work,we use the same method as the work above,The relic density of asymmetric dark matter is calculated in braneworld cosmology.and the Brane world cosmological scenario is a non-standard cosmolohical model.Hubble expansion rate is enhanced in brane world cosmology and it affects the relic abundance of asymmetric Dark Matter particles.In the context of asymmetric dark matter models,we found that the modified decou-pling predicted in non-standard cosmological models can either ’wash out’or amplify the asymmetry between the majority and minority dark matter components depending on whether the early time expansion rate is faster or slower than the standard expansion law respectively.We analyze how the relic abundance of asymmetric Dark Matter is changed in this model.We show that in such kind of nonstandard cosmological scenario,indirect detection of asymmetric Dark Matter is possible if the cross section is small enough which let the anti-particle abundance kept in the same amount with the particle.We show the indirect detection signal constraints can be used to such model only when the cross section and the 5 dimensional Planck mass scale are in appropriate values.