Detector characterization and Λb measurements with the upgrades of the ALICE Inner Tracking System

Abstract

The ALICE experiment at CERN is dedicated to study the properties of the strongly interacting matter and the Quark Gluon Plasma through heavy ion collisions at the LHC. During the 2020s, ALICE is entering a new era of measurements in the heavy flavour sector benefiting from the detector upgrades that will enhance its capabilities. The first part of this thesis provides an overview of the detector characterization and classification that was performed during the (pre) production phase of the upgrade of the ALICE Inner Tracking System (ITS) during the Long Shutdown 2. A detailed description of the tests that were used for the evaluation of the electrical response of the detector components and the data transmission are presented and accompanied by indicative results that reflect the detector quality. In the second part of the thesis, the impact of a further ITS upgrade, during the Long Shutdown 3, is studied on the beauty sector of heavy flavour and more precisely on the measurement of the Λb baryon. The significance and the signal over background ratio of measuring the Λb particle were estimated and compared for the two upgrades. Benefiting from the improved pointing resolution that the proposed future ultra-low mass detector will offer, an improvement especially in the low momentum region is reported. The research performed in this thesis reflects how well the latest technological advances combine with high energy physics and contribute to the understanding of our universe.