The influence of residual vertical dispersion on LEP performance

During LEP Operation for Luminosity production, the closed orbit is systematically corrected towards a reference orbit which has been empirically found to produce high luminosities. Machine studies have been undertaken to try and understand the mechanism by which the vertical closed orbit affects the luminosity. The dominant parameter has been found to be the residual vertical dispersion, in particular the residual vertical dispersion at the interaction points. This paper reports on studies to investigate how the quality of the closed orbit affects the residual vertical dispersion and especially the residual vertical dispersion at the interaction points.