Mu3e pixel detector construction, commissioning and first data analysis

The Mu3e experiment is designed to search for or exclude the rare decay process of a positive muon to two positrons and one electrons with a sensitivity representing an improvement of nearly four orders of magnitude over the previous experimental limits. By studying this decay, the Mu3e experiment seeks to uncover potential new physics beyond the Standard Model, as this decay is forbidden in the Standard Model without lepton flavor violation.

To observe this rare process, Mu3e must detect events from muon decays at rest with exceptional precision. This requires the detector to achieve outstanding vertex and momentum resolution for low-momentum particles. Such precision can only be realized through an ultra-lightweight tracking and vertexing system, achieved with a specialized design using high-voltage (HV) CMOS pixel detectors.

The University of Oxford plays a central role in the Mu3e experiment, with the crucial responsibility of producing and thoroughly testing the outer pixel tracking system. This outer tracker consists of ladders, each built from 18 individual HV CMOS chips, and the reliability of each sensor is paramount to the success of the detector. As part of this project, Aliki will be instrumental in developing a robust testing framework for the CMOS pixel sensors.

Her contributions will include the design and fine-tuning of a large-scale test setup, specifically tailored to assess each sensor's performance and ensure it meets the stringent criteria required for integration into the Mu3e detector. Her work on sensor testing is essential for validating functionality, durability, and reliability, securing the detector's overall performance.

Beyond sensor testing, Aliki will contribute significantly to the development of a quality control (QC) setup tailored for the "ladder" structure, which serves as the essential support framework for the outer pixel tracker. Each ladder must be meticulously assembled and meet rigorous standards to endure the demands of the experiment, and the QC setup is vital to achieving this.

Aliki's contributions to the QC process will streamline evaluation procedures, ensuring each ladder component is precisely constructed, resilient, and ready for long-term operational stability within the Mu3e detector system.

Following the QC and sensor validation phases, Aliki's role will progress to involvement in the initial commissioning and data-taking stages of the Mu3e detector. This phase will likely include an extended attachment to the Paul Scherrer Institute in Switzerland, where she will gain hands-on experience with detector operations and actively support the setup and calibration of the outer pixel tracker.

During this commissioning period-which will involve a sequence of engineering, cosmic, and calibration runs-Aliki is expected to work on developing the data analysis framework for the Mu3e detector. She will contribute to establishing the analysis pipeline, which will facilitate the first analyses of datasets collected by Mu3e. Her contributions in these stages will be critical to achieving the precision and sensitivity Mu3e needs to meet its ambitious physics goals, including potentially identifying evidence for lepton flavor violation in muon decays.

This project not only advances the Mu3e experiment's objectives but also serves as a unique opportunity for Aliki to acquire comprehensive expertise in detector development, testing, and analysis, positioning her to make valuable contributions to both the current project and the field of particle physics at large.