Low-x physics and W and Z production at the LHC

Abstract

W and Z production at the LHC occur at small Bjorken x, and are thus subject to the theoretical uncertainties of low-x physics. The implications of this for the PDF uncertainties on W and Z production are discussed, including the limitations this puts on their usefulness as luminosity monitors. The possibility of using LHC measurements to improve PDF uncertainties is discussed. Measurement of the W lepton decay spectra can improve the gluon PDFs, whereas measurement of the lepton asymmetry can give new information on valence distributions at small x.