A time-integrated analysis of Bd → π+π−π+π− at LHCb and simulations for Low Gain Avalanche Detectors (LGAD)

Friday, David (2023) A time-integrated analysis of Bd → π+π−π+π− at LHCb and simulations for Low Gain Avalanche Detectors (LGAD). PhD thesis, University of Glasgow.

Abstract

This thesis presents the time-integrated amplitude analysis of Bd → π+π−π+π− at the LHCb experiment during Run 2 data taking. It presents data selection of Bd mesons, with a yield of 126725 ± 504, and shows the amplitude model and full fits to the Run 2 (2015-2018) dataset. A longitudinal polarisation fraction of fL = 0.721 ± 0.01 ± 0.03 is reported with comparision to previous analyses. The extension of the analysis to a time and flavour-dependent analysis is discussed in the context of extracting a single solution to the unitarity angle α. Novel simulations of Low Gain Avalanche Detectors (LGAD) for the high luminosity LHC are also presented. Work was completed showing consistent behaviour at the device edge using trench termination, and through new radiation simulations, the gain degradation of LGAD devices was reported. Gain recovery was shown not to be feasible at fluences in excess of 1 × 1015 φneq.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Supervisor's Name: Soler, Professor Paul and Eklund, Professor Lars
• Date of Award: 2023
• Depositing User: Theses Team
• Unique ID: glathesis:2023-83485
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 16 Mar 2023 11:52
• Last Modified: 23 Mar 2023 09:58
• Thesis DOI: 10.5525/gla.thesis.83485
• URI: https://theses.gla.ac.uk/id/eprint/83485