Test Beam Measurements for the Upgrade of the CMS Pixel Detector and Measurement of the Top Quark Mass from Differential Cross Sections

In this dissertation, two different topics are addressed which are vital for the realization ofmodern high-energy physics experiments: detector development and data analysis. The first partfocuses on the development and characterization of silicon pixel detectors. To account for theexpected increase in luminosity of the Large Hadron Collider, the pixel detector of the CompactMuon Solenoid (CMS) experiment will be replaced by an upgraded detector with new front-endelectronics. Comprehensive test beam studies are presented which have been conducted to verifythe design and to quantify the performance of the new front-end in terms of tracking efficiency+0.3and spatial resolution. The tracking efficiency has been determined to be 99.7 −0.5 %, whilethe spatial resolution has been measured to be (4.80 ± 0.29) µm and (7.99 ± 0.23) µm along the100 µm and 150 µm pixel pitch, respectively. Furthermore, a new cluster interpolation method isproposed which utilizes the third central moment of the cluster charge distribution and achievesimprovements of the position resolution of up to 40 % over the conventional center of gravityalgorithm. In the second part of the thesis, an alternative measurement of the top quark massis presented. The mass is measured from the normalized differential production cross sections ofdileptonic top quark pair events with an additional jet. The measurement is performed on data√recorded by the CMS experiment at s = 8 TeV, corresponding to an integrated luminosity of19.7 fb−1 . Using theoretical predictions at next-to-leading order in perturbative QCD, the toppole+4.7quark pole mass is measured to be mt = 168.2 −2.1 GeV with a precision of about 2.0 %. Themeasurement is in agreement with other measurements of the top quark pole mass within theassigned uncertainties.Layer