Radiation Hard Hybrid Pixel Detectors, and a bbbar Cross Section Measurement at the CMS Experiment

Measurements of heavy flavor quark production at hadron colliders provide agood test of the perturbative quantum chromodynamics (pQCD) theory. Itis also essential to have a good understanding of the heavy quark productionin the search for new physics. Heavy quarks contribute to backgrounds andsignals in measurements of higher mass objects, such as the Higgs boson. Akey component to each of these measurements is good vertex resolution. Inorder to ensure reliable operation of the pixel detector, as well as confidencein the results of analyses utilizing it, it is important to study the effects ofthe radiation on the detector.In the first part of this dissertation, the design of the CMS silicon pixeldetector is described. Emphasis is placed on the effects of the high radiation environment on the detector operation. Measurements of the chargecollection efficiency, interpixel capacitance, and other properties of the pixelsensors as a function of the radiation damage are presented.In the second part, a measurement of the inclusive b¯ production cross sectionbusing the b → µD0 X, D0 → K π decay chain with data from the CMS experiment at the LHC is presented. The data were recorded with the CMS experiment at the Large Hadron Collider (CERN) in 2010 using unprescaled singlemuon triggers corresponding to a total luminosity of 25 pb−1 . The differential cross section is measured for pDT