Scalar Neutrino Dark Matter In BLMSSM

Since the 1920s,with the further development of scientific research on the universe,sci-entists have discovered that some observational facts contradict with the existing physical the-ories.These observational facts have prompted people to construct a model of matter named”dark matter”to bridge the gap between actual observation and theory.As the main component of matter and energy in the universe,dark matter has attracted more and more attention in recent years.But there's still a lot of confusion about what it is.In this paper,we discuss the possibility of the lightest scalar neutrino as dark matter can-didate in the BLMSSM model using particle physics methods.BLMSSM is an extension of the Minimum Supersymmetric Standard Model(MSSM).Its local gauge symmetry group is SU(3) _C×SU(2) _L×U(1)_Y×U(1)_B×U(1)_L.Assuming that the lightest scalar neutrino is the dark matter candidate,we calculate the numerical results of the remnant density in detail and find a reasonable parameter space.Finally,the numerical discussion can limit the parameter space and provide some reference for the future study and exploration of dark matter.The first part of this paper introduces the foundation of Standard Model(SM)and MSS-M at length.The second chapter is the observation facts of dark matter and the related basic knowledge.In chapter 3,the BLMSSM model is introduced in detail,and its superpotential,soft break term and some matrices are given.The next part shows some of the knowledge in cosmology,from which we can calculate the density of relics;In Chapter 5,our calculation results are presented,and the correctness of the model can be verified by bringing the results back to the formula of relic density in the previous chapter.And then there's some analysis of the results that we did;The last chapter is a more concise discussion and summary of this work.