Luminosity determination in ALICE with T0 and V0 detectors

The contributions of the two ALICE forward detectors, V0 and T0, to the luminosity and multiplicity study, and beam diagnostics are discussed. Already the runs during the LHC commissioning period should provide sufficient data for luminosity and multiplicity determination and for establishing the position of the interaction point along longitudinal and transverse axis. Precise determination of the relative luminosity and its monitoring is required as it enters to the cross section calculations of all physics processes. The goal is to keep the systematic error of the relative luminosity in ALICE within 5 %