Dark Matter Detection in Supersymmetric Models with Non-Universal Gaugino Masses

SUSY is one of the most promising new physics ideas, and will soon be tested at high energy accelerators like the CERN LHC. Moreover SUSY provides a good candidate for cold dark matter (CDM). In this dissertation, we investigated phenomenology of SUSY models with non-universal gaugino masses (NUGM) at colliding experiments using event generators such as ISAJET and examined direct and indirect detection rates of relic neutralino CDM in the universe. The motivation of these models is that in most of mSUGRA parameter space, the relic density $Omega_{ z_1}h^2$ is considerably larger than the WMAP measurement, and it is well known that if non-universal gaugino masses are allowed, then qualitatively new possibilities arise that are not realized in the mSUGRA model. Our first NUGM attempt is to allow a mixed wino-bino lightest SUSY particle (LSP) by lowering $SU(2)$ gaugino mass $M_2$ at the weak scale from its mSUGRA value while keeping the hypercharge gaugino mass $M_1$ fixed ({it Mixed Wino Dark Matter}). In this model, wino-like $ ilde{Z_1}$ with sufficiently low $M_2$ compared to $M_1$ enhances $ ilde{Z_1} ilde{Z_1} ightarrow W_{1}^{+} W_{1}^{-}$ annihilations to reach the WMAP measured relic density. The second attempt is study on the NUGM model with different signs of $M_1$ and $M_2$ ({it Bino-Wino Co-Annihilation Scenario}). In this case, there is little mixing, so that $ ilde{Z_1}$ remains nearly a pure bino or a pure wino. By increasing $M_1 simeq M_2$, enhanced bino-wino co-annihilation can achieve the relic neutralino abundance. The final attempt of NUGM models is lowering the $SU(3)$ gaugino mass to diminish the effect of the large top quark Yukawa coupling in the running of the higgs mass, so that the value of superpotential $mu$ parameter gets efficiently low to give rise to mixed higgsino dark matter ({it Mixed Higgsino Dark Matter}). Consequences of these NUGM model studies show us that relaxing universality of gaugino masses in SUSY models leads to enhanced direct and indirect dark matter detection rates and reduced $m_{ ilde{Z_2}}-m_{ ilde{Z_1}}$ mass gap so that the LHC and ILC can distinguish each NUGM model from others. Finally, we found that models with well-tempered neutralinos, where the composition of the neutralino is adjusted to give observed relic density, yield target cross sections which are detectable at proposed experiments.