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University of Cambridge

Doubly charmed B decays with the LHCb experiment

Abstract

dc:description.abstract

$CP$ violation is a necessary ingredient to create a matter-antimatter asymmetry. However, the amount of $CP$ violation incorporated in the Standard Model is orders of magnitude too small to explain the observed asymmetry. This thesis documents two studies of $CP$ violation with doubly charmed $B$ decays. Both were performed using Run I data collected by the LHCb experiment in $pp$ collisions at the LHC. This corresponds to 1.0 fb-1 collected at a centre-of-mass energy of 7 TeV and 2.0 fb-1 collected at a centre-of-mass energy of 8 TeV. The first analysis is a search for Bc+ decays to two charm mesons, Bc+\to D(*)+(s)D(*), where the second charm meson is either D0 or \overline{D}{}0, which are sensitive to the CKM angle \gamma. No evidence for signal is found and limits are set on twelve decay modes. The second analysis is the measurement of the $CP$ asymmetry in B+\to D+(s) \overline{D}{}0 decays. The results are \begin{align*} \mathcal{A}^{CP}(B^+\to D^+_{s} \overline{D}{}^0) &= (-0.4\pm 0.5\pm 0.5)\%,\\ \mathcal{A}^{CP}(B^+\to D^+ \overline{D}{}^0) &= (+2.3\pm 2.7\pm 0.4)\%, \end{align*} where the first uncertainty is statistical and the second systematic. This is the first measurement of \mathcal{A}CP(B+\to D+s \overline{D}{}0) and the most precise measurement of \mathcal{A}CP(B+\to D+\overline{D}{}0) to date. The results are consistent with $CP$ symmetry.

Degree

thesis:*
Name dc:type.qualificationname
Doctor of Philosophy (PhD)
Level dc:type.qualificationlevel
Doctoral
Grantor dc:publisher.institution
University of Cambridge
Year dc:date.issued
2019

Author and committee

dc:creator, dc:contributor.*
Author dc:creator
  • Tully, Alison Maria
Advisor dc:contributor.advisor
  • Gibson, Valerie

Subjects

dc:subject × 7

Rights

dc:rights
Language dc:language
en

Identifiers

dc:identifier.*
Author Identifier
0000-0002-8712-9055
OAI identifier oai:identifier
oai:www.repository.cam.ac.uk:1810/297741

Chain of custody

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Harvested from
Cambridge University
Base URL
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Last updated
2026-07-22
Source record
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citation

Tully, Alison Maria. Doubly charmed B decays with the LHCb experiment. Doctoral thesis, University of Cambridge, 2019. https://doi.org/10.17863/CAM.44796