Development of the quality test protocol for the DEPFET pixel detectors and top-quark mass measurement at high energy e+^{+}e−^{-} colliders

The need of explanation to the nature phenomenons are unstoppable and likewise the necessity of new machines to continue discovering them. On this content, several projects, with different approaches, are under being developed. The International Linear Collider (ILC) and the Compact Linear Collider (CLIC) will use electrons and positrons collision, on the energy range from hundreds of GeV to the multi-TeV scale. On the other hand, the SuperKEKB, which uses $e^{+}e^{-}$ interaction at intermediate energies, generating unprecedented luminosities to study the $B\bar{B}$ processes with very high accuracy. The work presented here entered on this content to perform a tiny contribution. The thesis was divided in two main topics. First part is dedicated to the study and development of the DEPFET system. DEPFET is an active pixel technology, characterized by its excellent position reconstruction, its low material budget and low power consumption, which is capable to cope with all the requirement of the future $e^{+}e^{-}$ colliders. For this reason, DEPFET is one of the candidates for the (ILC) and the baseline technology for the Belle II PXD (SuperKEKB). On this content, the DEPFET prototypes for Belle II PXD were presented, likewise, the process of construction of the PXD shell, to contextualize and motivated the development of a quality control protocol using a needles card. The process of design and test of the distinct needles card prototypes were described, together with a proposed testing protocol. This work resulted in a complete setup, with all the mechanical parts, the electronic boards and software, mounted and prepared to be used during the PXD production. The second study is focused on the measurement of the top-quark mass. This part has introduced a new observable, $B(m_{t},\zeta_{S'})$, which uses the cross section of the $t\bar{t}$ radiative events to obtain the mass of the top-quark in the continuum. The study has been performed on $e^{+}e^{-}$ collider scenario, to take advantage of this new environment and, potentially, reach unprecedented sensitivities. A partonic level study was done in order to obtain the maximum potential sensitivity achievable on the ILC-$500$ GeV physics scenario. The calculations was performed, independently, using the ISR and FSR particles and then, combining both processes. Afterwards, to approach towards a realistic study, the hadronization and the basic detector effect were included. Moreover, the study was extended to CLIC-$380$ GeV and ILC-$1000$ GeV. $B(m_{t},\zeta_{S'})$ does not require a specific interaction energy the study of the mass can be done not only over the production threshold but in the continuum, therefore, the mass can be defined on a good renormalization system, being sensitive to its running. On this content, the sensitivity to the running of the top-quaks mass was proved. Finally, the study of the systematic errors were performed and a method to minimize its effect was proposed. The results obtained proved that the resolution of $B(m_{t},\zeta_{S'})$ are way below the methods currently used in hadron colliders and in the same order of the threshold measurements on the ILC

Top quark mass measurement in radiative events at electron-positron colliders

In this letter, the potential of linear e+e− colliders to measure the top quark mass in a suitable short-distance scheme in radiative events is evaluated. We present a calculation of the differential cross section for production of a top quark pair in association with an energetic photon from initial state radiation, as a function of the invariant mass of the tt ̄system. This matched calculation includes the QCD enhancement of the cross section around the tt ̄ production threshold and remains valid in the continuum well above the threshold. The uncertainty in the top mass determination is evaluated in realistic operating scenarios for the Compact Linear Collider (CLIC) and the International Linear Collider (ILC), including the statistical uncertainty and the theoretical and experimental systematic uncertainties. With this method, the top quark mass can be determined with a precision of 110 MeV in the initial stage of CLIC, with 1 ab−1 at √s = 380 GeV, and with a precision of approximately 150 MeV at the ILC, with L = 4 ab−1 at √s = 500 GeV. Radiative events allow measurements of the top quark mass at different renormalization scales, and we demonstrate that such a measurement can yield a statistically significant test of the evolution of the MSR mass mMSR(R) for scales R < mt

Data quality monitors of vertex detectors at the start of the Belle II experiment

The Belle II experiment features a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric e+e− collider at KEK in Tsukuba, Japan. The accelerator completed its first phase of commissioning in 2016, and the Belle II detector saw its first electron-positron collisions in April 2018. Belle II features a newly designed silicon vertex detector based on double-sided strip layers and DEPFET pixel layers. A subset of the vertex detector was operated in 2018 to determine background conditions (Phase 2 operation). The collaboration completed full detector installation in January 2019, and the experiment started full data taking. This paper will report on the final arrangement of the silicon vertex detector part of Belle II with a focus on online monitoring of detector conditions and data quality, on the design and use of diagnostic and reference plots, and on integration with the software framework of Belle II. Data quality monitoring plots will be discussed with a focus on simulation and acquired cosmic and collision data

Alignment for the first precision measurements at Belle II

International audienceOn March 25th 2019, the Belle II detector recorded the first collisions delivered by the SuperKEKB accelerator. This marked the beginning of the physics run with vertex detector.The vertex detector was aligned initially with cosmic ray tracks without magnetic field simultaneously with the drift chamber. The alignment method is based on Millepede II and the General Broken Lines track model and includes also the muon system or primary vertex position alignment. To control weak modes, we employ sensitive validation tools and various track samples can be used as alignment input, from straight cosmic tracks to mass-constrained decays.With increasing luminosity and experience, the alignment is approaching the target performance, crucial for the first physics analyses in the era of Super-BFactories. We will present the software framework for the detector calibration and alignment, the results from the first physics run and the prospects in view of the experience with the first data

Alignment for the first precision measurements at Belle II

On March 25th 2019, the Belle II detector recorded the first collisions delivered by the SuperKEKB accelerator. This marked the beginning of the physics run with vertex detector. The vertex detector was aligned initially with cosmic ray tracks without magnetic field simultaneously with the drift chamber. The alignment method is based on Millepede II and the General Broken Lines track model and includes also the muon system or primary vertex position alignment. To control weak modes, we employ sensitive validation tools and various track samples can be used as alignment input, from straight cosmic tracks to mass-constrained decays. With increasing luminosity and experience, the alignment is approaching the target performance, crucial for the first physics analyses in the era of Super-BFactories. We will present the software framework for the detector calibration and alignment, the results from the first physics run and the prospects in view of the experience with the first data

Data quality monitors of vertex detectors at the start of the Belle II experiment

The Belle II experiment features a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric e+e− collider at KEK in Tsukuba, Japan. The accelerator completed its first phase of commissioning in 2016, and the Belle II detector saw its first electron-positron collisions in April 2018. Belle II features a newly designed silicon vertex detector based on double-sided strip layers and DEPFET pixel layers. A subset of the vertex detector was operated in 2018 to determine background conditions (Phase 2 operation). The collaboration completed full detector installation in January 2019, and the experiment started full data taking. This paper will report on the final arrangement of the silicon vertex detector part of Belle II with a focus on online monitoring of detector conditions and data quality, on the design and use of diagnostic and reference plots, and on integration with the software framework of Belle II. Data quality monitoring plots will be discussed with a focus on simulation and acquired cosmic and collision data

International Large Detector: Interim Design Report

The ILD detector is proposed for an electron-positron collider with collision centre-of-mass energies from 90~\GeV~to about 1~\TeV. It has been developed over the last 10 years by an international team of scientists with the goal to design and eventually propose a fully integrated detector, primarily for the International Linear Collider, ILC. In this report the fundamental ideas and concepts behind the ILD detector are discussed and the technologies needed for the realisation of the detector are reviewed. The document starts with a short review of the science goals of the ILC, and how the goals can be achieved today with the detector technologies at hand. After a discussion of the ILC and the environment in which the experiment will take place, the detector is described in more detail, including the status of the development of the technologies foreseen for each subdetector. The integration of the different sub-systems into an integrated detector is discussed, as is the interface between the detector and the collider. This is followed by a concise summary of the benchmarking which has been performed in order to find an optimal balance between performance and cost. To the end the costing methodology used by ILD is presented, and an updated cost estimate for the detector is presented. The report closes with a summary of the current status and of planned future actions

The ILD detector at the ILC

The International Large Detector, ILD, is a detector concept which has been developed for the electron-positron collider ILC. The detector has been optimized for precision physics in a range of energies between 90 GeV and 1 TeV. ILD features a high precision, large volume combined silicon and gaseous tracking system, together with a high granularity calorimeter, all inside a 3.5 T solenoidal magnetic field. The paradigm of particle flow has been the guiding principle of the design of ILD. In this document the required performance of the detector, the proposed implementation and the readiness of the different technologies needed for the implementation are discussed. This is done in the framework of the ILC collider proposal, now under consideration in Japan, and includes site specific aspects needed to build and operate the detector at the proposed ILC site in Japan