Distinguishing New Physics Scenarios at a Linear Collider with Polarized Beams

Numerous non-standard dynamics are described by contact-like effective interactions that can manifest themselves through deviations of the cross sections from the Standard Model predictions. If one such deviation were observed, one should try to identify to a given confidence level the actual source among the possible non-standard interactions that in principle can explain it. We here estimate the potential identification reach on different New Physics effective interactions, obtainable from the angular distributions of lepton pair production processes at the planned International Linear Collider with polarized beams. The models discussed are the interactions based on gravity in large and in TeV^{-1} extra dimensions and the compositeness-inspired four-fermion contact interactions. The availability of both beams polarized in many cases plays an essential role in enhancing the identification sensitivity.