A Proposal for a Luminosity Monitor for CMS Based on Small Angle Pixel Telescopes

Measurement and monitoring of the luminosity in the CMS experiment will be essential both for physics measurements (e.g., production cross sections of top, Higgs and SUSY) and for accurate simulation of rate dependent detector characteristics. Although, in principle, the luminosity can be determined from the LHC beam parameters, it will be crucially important for each experiment to independently determine its luminosity. We present here a modest proposal for a CMS luminosity monitoring system consisting of a set of small angle pixel telescopes. This system is based largely on components and technologies already developed or being developed for the CMS pixel detector including the CMS pixel readout chip. The proposed system will determine the individual bunch- to-bunch luminosity variations to a precision of better than 1% over a 1 s time scale.