Measurement of the CKM angle $\gamma$ and development of a novel, combined GGSZ analysis of $B \rightarrow D^{(*)} h^{(*)}$ decays at LHCb
type: CreativeWork
description: The angle $\gamma$ is a fundamental parameter of the Standard Model, within which it quantifies the degree to which CP violation is permitted. It is presently one of the least well-constrained parameters of the CKM sector, which embodies the description of quark interactions. This thesis details work undertaken by the author at the LHCb experiment with the aim of reducing the uncertainty in $\gamma$. It describes a measurement performed using a Dalitz analysis of $B^0 \rightarrow D K^{*0}$ decays, and a study which extends this work to a simultaneous Dalitz analysis of several $B$-meson decay modes of the form $B \rightarrow D^{(*)} K^{(*)}$. In each analysis, $\gamma$ is extracted by studying the interference between CP eigenstates $D^0$ and $\overline{D^0}$ in the common final state $D \rightarrow K_S^0 \pi^+ \pi^-$, where $D$ represents either a $D^0$ or $\overline{D^0}$ meson. The measurement of $\gamma$ in $B^0 \rightarrow D K^{*0}$ decays includes the full $3\mathrm{fb}^{-1}$ Run 1 dataset gathered at LHCb, and uses a model-dependent approach to yield the 'Cartesian parameters' $\begin{eqnarray*} x_- &=& -0.15 \pm 0.14 \pm 0.03 \pm 0.01,\\ y_- &=& \phantom{-}0.25 \pm 0.15 \pm 0.06 \pm 0.01,\\ x_+ &=& \phantom{-}0.05 \pm 0.24 \pm 0.04 \pm 0.01, \quad \text{and}\\ y_+ &=& -0.65~^{+0.24~~}_{-0.23~~} \pm 0.08 \pm 0.01, \end{eqnarray*}$ where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the $D \rightarrow K_S^0 \pi^+ \pi^-$ amplitude model used. These results imply (the relation between $\{x_\pm,y_\pm\}$, and angle $\gamma$, is described within) a value for $\gamma$ of $\begin{equation*} \gamma = (80^{+21}_{-22} )^\circ. \end{equation*}$ In the simultaneous analysis, both model-dependent and model-independent approaches to the determination of $\gamma$ are studied. Using the full Run 1 LHCb dataset, the model-dependent approach yields preliminary uncertainties of $\begin{eqnarray*} \sigma_{x_-} &=& \pm 0…
abstract: The angle $\gamma$ is a fundamental parameter of the Standard Model, within which it quantifies the degree to which CP violation is permitted. It is presently one of the least well-constrained parameters of the CKM sector, which embodies the description of quark interactions. This thesis details work undertaken by the author at the LHCb experiment with the aim of reducing the uncertainty in $\gamma$. It describes a measurement performed using a Dalitz analysis of $B^0 \rightarrow D K^{*0}$ decays, and a study which extends this work to a simultaneous Dalitz analysis of several $B$-meson decay modes of the form $B \rightarrow D^{(*)} K^{(*)}$. In each analysis, $\gamma$ is extracted by studying the interference between CP eigenstates $D^0$ and $\overline{D^0}$ in the common final state $D \rightarrow K_S^0 \pi^+ \pi^-$, where $D$ represents either a $D^0$ or $\overline{D^0}$ meson. The measurement of $\gamma$ in $B^0 \rightarrow D K^{*0}$ decays includes the full $3\mathrm{fb}^{-1}$ Run 1 dataset gathered at LHCb, and uses a model-dependent approach to yield the 'Cartesian parameters' $\begin{eqnarray*} x_- &=& -0.15 \pm 0.14 \pm 0.03 \pm 0.01,\\ y_- &=& \phantom{-}0.25 \pm 0.15 \pm 0.06 \pm 0.01,\\ x_+ &=& \phantom{-}0.05 \pm 0.24 \pm 0.04 \pm 0.01, \quad \text{and}\\ y_+ &=& -0.65~^{+0.24~~}_{-0.23~~} \pm 0.08 \pm 0.01, \end{eqnarray*}$ where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the $D \rightarrow K_S^0 \pi^+ \pi^-$ amplitude model used. These results imply (the relation between $\{x_\pm,y_\pm\}$, and angle $\gamma$, is described within) a value for $\gamma$ of $\begin{equation*} \gamma = (80^{+21}_{-22} )^\circ. \end{equation*}$ In the simultaneous analysis, both model-dependent and model-independent approaches to the determination of $\gamma$ are studied. Using the full Run 1 LHCb dataset, the model-dependent approach yields preliminary uncertainties of $\begin{eqnarray*} \sigma_{x_-} &=& \pm 0…
author: Smith, Jackson William
language: en
keywords: Physics, CP, hadron, B-meson, decay, LHCb, RICH, gamma, unitarity, isobar model, Dalitz, cfit, multivariate analysis, machine learning, likelihood fitting, roofit, particle, overconstrain, triangle, cartesian, GGSZ, resonance
license: https://www.repository.cam.ac.uk/bitstreams/683f501e-2f95-4cfe-a3b8-55fb80c1e1d2/download
license: https://creativecommons.org/licenses/by-nc-sa/4.0/
date published: 2019-11-30
date modified: 2026-07-22T22:23:56Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.44745