Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.728130
Title: Flavour studies with LHCb : b-meson mixing, lepton-flavour violation and the velo upgrade
Author: Bird, Thomas
ISNI:       0000 0004 6497 9430
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2016
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Abstract:
Semileptonic B decays of the type Bq⁰→Dq⁻μ⁺ν (where Dq⁻→K⁻K⁺pie⁻) are selected and their lifetimes are corrected using a statistical simulation-based correction called the k-factor. Using 1 fb⁻¹ of LHCb data the B⁰ and Bs⁰ mixing frequencies are measured to be Deltamd = ( 0.503 ± 0.011 (stat) ± 0.013 (syst) ) ps⁻¹ and Deltams = ( 17.93 ± 0.22 (stat) ± 0.15 (syst) ) ps⁻¹. We exclude the null hypothesis of no mixing for the B⁰ and Bs⁰ by 5.8 and 13.0 standard deviations respectively. This is the first observation of Bs Bsbar mixing using only semileptonic B decays. The lepton flavour violating decay D⁰→eμ is searched for, using tagged D⁰ decays from D*→D⁰pie, and the measurement is normalised using D⁰→K⁻pie⁺ decays. No evidence is seen of an excess over the expected background and so a limit is placed B(D⁰→eμ) < 1.3×10⁻⁸ at a 90% confidence level using 3 fb⁻¹ of LHCb data. This improves the previous measurement by a factor of 20 and is the world's best measurement. Possible upgrades to the LHCb VELO detector are simulated and aspects of the upgraded detector are optimised to ensure that all tracks within the angular acceptance can be detected with high precision. Finally the simulated performance of the current and upgraded VELO detectors are compared.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.728130  DOI: Not available
Keywords: Flavour physics ; B mixing ; Lepton flavour violation ; LHCb ; VELO upgrade
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