Identification of large extra spatial dimensions at the LC

Abstract

We discuss the possibility to cleanly distinguish, in electron-positron annihilation into fermion pairs at a high energy collider, the indirect manifestations of graviton exchange from those of four-fermion contact interactions. The method is based on cross section asymmetries emphasizing the spin-2 character of graviton exchange and is explicitly applied to the ADD scenario for gravity in extra dimensions. The availability of initial beams longitudinal polarization is also taken into account. For typical c.m. energies and time-integrated luminosities foreseen at the International Linear Collider [\sqrt s=0.5-1 TeV, L_{int}=50-1000 fb^{-1}], a 5\sigma identification reach as high as 3.5-5.8 TeV for the mass scale M_H relevant to the ADD model can be obtained, while the size of the reach on the mass scales Lambda characterizing four-fermion contact interactions can be of the order of 45-65 TeV.