Constrains On WIMP Parameters From Dark Matter Direct Detection Experiments

Beginning from the invention of “Dark Matter”, the dissertationintroduces that the non-baryonic matter dominates the dark matter contentin the universe. Among the various dark matter candidates, the neutralinopredicted by super-symmetric theory is now the most popular one. Wheninterpreting the data from a direct detection result, one must take intoconsideration the uncertainty from experiments, such as energy detectionefficiency, threshold cut-off and energy resolution, and the uncertaintyfrom the cosmological parameters as well. After some analysis of theimpacts on the calculation results from theses uncertainties, the detailedcalculation process of WIMP parameters is given under the assumptionthat the background events are well understood for the experiments.However, limitations are shown for these simplified calculation methods.To have a general view of all the existing dark matter direct detectionresults, a model independent method is introduced in the last Chapter ofthis dissertation. Using the model independent method, the WIMP-nucleoncoupling constants and their limits for both spin independent and spindependent interaction are obtained. Thus a conclusion is given that noconclusive evidence has been found by the direct detection experiments ofdark matter. The model independent calculation is a more general methodto be used in the comparison of different experiments results.