Detecting Primordial Black Holes With The Earth-Moon Binary System

Primordial black holes(PBHs)are of great value to the research of cosmology,astronomy and fundamental physics,which have attracted wide attention recently.First of all,PBHs,as a kind of black holes formed in the early universe,contain a lot of information about the early universe.Second,PBHs are a good candidate for explaining the origin of black holes that do not form in standard astrophysical processes;Finally,primordial black holes can be candidates for the dark matter.At present,there is still a wide window about the proportion of the PBHs in the dark matter and the continuous improvement of the accuracy of the lunar laser ranging experiment provides certain conditions to fill this window.In this thesis we propose a new way to detect sublunar-mass PBHs by direct observations of the Earth-Moon binary system.Our method is based on treating PBH as a perturbation term,by assuming that the PBH is sweeping across the solar system with a sublunar mass and is far away from the Earth-Moon binary(much greater than 1AU).Under this perturbation treatment,a framework is proposed in this paper to calculate the orbits of a general binary system,such as the Earth-Moon system.We calculate the time evolution of the orbital elements and the variation of the change in the Earth-Moon distance under the influence of PBH perturbations.In addition,we also quantitatively study the numerical results of the variation in Earth-Moon distance change over time for different initial conditions and its dependence on the parameters(i,Ω,ω,m2,b)in the initial conditions.Our numerical results show that the EarthMoon distance is sensitive to the initial values of the system.In most cases,the longduration interactions between the PBH and the Earth-Moon system can induce lasting imprints on the Earth-Moon’s orbit,and these imprints can accumulate over time,eventually giving rise to the deviation of the moon’s orbit can be observed,which can be used to infer the properties of the PBH.