NEUTRALINO DARK MATTER SEARCHES

We consider the lightest neutralino, a general combination of photino, zino and higgsinos in the minimal supersymmetric extension of the standard model, as a component of the dark matter in the halo of our galaxy. We compute the neutralino cosmological relic abundance to estimate its contribution to the dark halo density. Due to its spin-independent coherent interactions with nuclei, mediated mainly by Higgs bosons, neutralinos may be efficiently captured by the earth and the sun or interact in detectors. They could thus be detected in indirect and direct searches. Accelerator bounds have recently severely restricted the parameter space. We study neutralinos lighter than the W-boson and find that present dark matter searches impose practically no bounds in the regions allowed by accelerators. We show that part of those regions will be accessible to improved searches in the near future (particularly, looking for upgoing muons in underground detectors).