Q-balls Formation And The Production Of Gravitational Waves With Non-minimal Gravitational Couplings

In order to explain the phenomenon of baryon asymmetry in the universe,several baryogenesis mechanisms have been proposed on the premise of satisfying Sakharov's condition.Among them,the Affeck-Dine mechanism can effectively generate baryon number asymmetry in the supersymmetry theory.The Minimum Supersymmetric Standard Model(MSSM)is the simplest supersymmetric extension of the Standard Model.In MSSM,the direction of many fields has a scalar potential of almost zero,that is,a large vacuum expectation.These directions are called flat directions,which are generally composed of squarks and sleptons.In the period of inflation,these squarks and sleptons move freely in the potential to form scalar condensates.At the end of inflation,the condensates will be broken up due to the effect of the primary disturbance of the universe.During the decay process,the squarks and sleptons will be converted into baryon/lepton number of ordinary particles.So the flat direction in MSSM is a natural candidate for AD field in the Affeck-Dine mechanism.Q-ball depends on the effective potential of the scalar field,which had been discussed for different SUSY breaking types.On the other hand,the AD fields can have a direct coupling to the Ricci scalar R,which can change the shape of the effective potential and possibly amend the GW signals.Our work mainly surveys the impact of the non-minimal couplings of AD fields to gravity in gravity mediated supersymmetry breaking.By simulating the evolution of the AD field motion of equation and the energy-momentum tensor equation,we found that 1)Adding the non-minimum gravitational coupling,the potential can still form the Q-ball.And the growth rate and peak frequency of GWs depend on the non-minimum coupling parameter.2)Without the non-minimum gravitational coupling,the value of K must be less than zero(-0.01?-0.1),and no Q-ball will be formed when K=0.In our work,the new contribution in the potential enables the formation of the Q-ball even when K=0 and K>0,which has not been studied before.On September 14,2015,the LIGO detector in the United States detected gravitational wave(GW)for the first time,which confirmed Einstein's prediction about gravitational waves and also opened a new window of gravitational wave astronomy.Gravitational wave is the disturbance of space-time itself,which is not penetrated or absorbed and carries the whole information of the source.The information of the source can be obtained by detecting and studying the gravitational wave signal.After the end of cosmic inflation,the flat direction in the theory of supersymmetry can form the Q-ball.The formation process is inhomogeneous,non-spherical and anisotropic,which will inevitably lead to the generation of gravitational waves.This kind of gravitational wave signal contains the state of the early universe and the physical information of high energy scale,so the research on the formation of Q-ball is of great significance.As the gravitino mass is given by8)_3/2=F/(?)3M_p,low SUSY breaking scale F may cause low GW frequencies.If such stochastic GW signal are detected,it may give interesting information on SUSY breaking scale.