Probing slepton mass nonuniversality at e+e- linear colliders -: art. no. 095008

There are many models with nonuniversal soft SUSY breaking sfermion mass parameters at the grand unification scale. Even in the MSUGRA model scalar mass unification might occur at a scale closer to M-Planck, and renormalization effects would cause a mass splitting at M-GUT. We identify an experimentally measurable quantity Delta that correlates strongly with deltam(2) = m((e) over tildeR)(2) (M-GUT)-m((e) over tildeL)(2) (M-GUT), and which can be measured at electron-positron colliders provided both selectrons and the chargino are kinematically accessible. We show that if these sparticle masses can be measured with a precision of 1% at a 500 GeV linear collider, the resulting precision in the determination of Delta may allow experiments to distinguish between scalar mass unification at the GUT scale From the corresponding unification at Q similar toM(Planck). Experimental determination of Delta would also provide a distinction between the MSUGRA model and the recently proposed gaugino-mediation model. Moreover, a measurement of Delta (or a related quantity Delta') would allow for a direct determination of deltam(2).