The Phenomenology Of WIMP Dark Matter Model

The concept of dark matter has been proposed for a hundred years,but we still know little about it.Dark matter has become one of the most important fundamental scientific problems to be solved in this century.Although many astronomical and cosmological evidences show that there is a large amount of dark matter in the universe,almost all of these evidences can only prove that dark matter has gravitational characteristics.If dark matter is a fundamental particle,what is its mass?Does it participate in other interactions besides gravity?If so,how strong are the interactions?The Standard Model cannot explain these questions.Scientists have proposed various dark matter models,and the mass range of dark matter candidates reaches an astonishing 80 orders of magnitude.This makes a challenge for the search for dark matter,because no single experiment can cover such a wide range of dark matter mass.Therefore,in recent decades,dark matter experiments have focused more on the most theoretically motivated dark matter candidate,Weakly Interacting Massive Particles(WIMPs).According to the theoretical characteristics of WIMPs,scientists have proposed three detection methods to search for dark matter particles:indirect detection(searching for ordinary particles produced by the annihilation or decay of dark matter particles in the universe),direct detection(searching for observable signals produced by the collision of dark matter particles with target nuclei or electrons in underground laboratory),and collider detection(accelerating high-energy particle beams to collide and produce dark matter particles).After years of experimental search,some suspected WIMP signals have been detected,such as the Galactic Center GeV gamma-ray Excess(GCE),the AMS-02 antiproton excess and the positron spectrum excess,etc.In addition,the anomaly or excess found in other particle physics experiments may also be evidence left by WIMPs,such as the CDF Ⅱ W-boson mass excess and the muon g-2 anomaly,etc.In fact,we cannot draw qualitative conclusions about dark matter based solely on a single experimental signal.However,by combining multiple anomalous or excess signals from different experiments,we can more rigorously constrain many important model parameters including the WIMP mass.Moreover,this can provide theoretical basis and predictions for future experimental tests.This is the research motivation of this thesis.We first studied the W-boson mass excess based on one of the simplest dark matter models,the inert two Higgs doublet model(i2HDM).This study obtained two important conclusions:(1)Considering W-boson mass anomaly,the parameter space with dark matter mass heavier than 500 GeV is likely to have been completely excluded;(2)Dark matter with a mass between 54 and 74 GeV can naturally explain the W-boson mass excess,and dark matter within this range can produce detectable GeV γ-ray and antiproton signals in the Galaxy without the parameter fine-tuning.These two signals are likely to be the GCE and the antiproton excess observed by Fermi-LAT and AMS-02.The Next-to-Minimal Supersymmetric Standard Model(NMSSM)is the second simplest Supersymmetry.Inspired by the fact that light sparticles can contribute to additional muon g-2,we found that dark matter with a mass between 180 and 280 GeV can jointly explain the excess of W boson mass and muon g-2 anomaly measured by E989.More importantly,this mass range for dark matter will soon be fully tested by direct detection experiments.We also conducted a systematic study on muonphilic dark matter models.We found that in order to fit the GCE spectrum well and satisfy the correct dark matter relic density,resonance mechanism must be introduced by fine-tuning model parameters.Moreover,to better understand the possible physical connections between positron/electron cosmic ray excesses and dark matter,it is important to further investigate and understand the astrophysical backgrounds.Therefore,in the final part of thesis,we studied the possibility of explaining the primary electron excess by nearby supernova remnants.We found that the nearby source Monogem can not only contribute to the excess of primary electrons but also explain the structural features of the proton spectrum measured by DAMPE.