Improved measurement of parton distribution functions and   $\alpha_s(M_Z)$ with the LHeC
  The potential of the LHeC, a future electron-proton collider, for precision Deep Inelastic Scattering measurements is reviewed with particular emphasis on the reduction of uncertainties on the parton distribution functions (PDFs) of the proton and on the measurement of $\alpha_s(M_Z)$. The interpretation of possible Beyond Standard Model (BSM) signals at the LHC is crucially dependent on precise knowledge of the predictions of the Standard Model (SM) and the uncertainties on PDFs and $\alpha_s(M_Z) $are a limiting factor. The LHeC project, running in parallel with later stages of LHC running, would provide much improved precision on the PDFs as compared to the precision expected from LHC data alone. 
A.M.Cooper-Sarkar (for the LHeC study group)
hep-ph hep-ex