Precision study of supersymmetry at future lineare+e−colliders

We discuss a possible strategy for supersymmetry searches and studies at future linear ${\mathit{e}}^{+}$ ${\mathit{e}}^{\mathrm{-}}$ colliders. We demonstrate their effectiveness by Monte Carlo analyses with full angular correlations under realistic experimental conditions including initial state radiation and beamstrahlung effects. The importance of precision measurements of supersymmetry parameters is emphasized. We demonstrate that the precision on mass measurements can be as good as 1% for leptonic and 3% for hadronic final states. A detailed study on the first superparticle alone gives us an upper bound on the next superparticle. We can also test the basic mass relations assumed in grand unified models or supergravity, such as the gaugino mass relations or the universal scalar mass assumption in a variety of ways. The polarized electron beam plays a crucial role in this study.