Measurements of CP violation in mixing of Bs mesons and the Ds production asymmetry at LHCb

Abstract

This thesis reports two measurements performed using proton-proton collision data collected by the LHCb detector in 2011 and 2012, corresponding to an integrated luminosity of 3 inverse femtobarn and centre-of-mass energies of 7 and 8 TeV respectively. The first measures the CP asymmetry in Bs-anti-Bs oscillations, called asls. This is measured in inclusive Bs and anti-Bs to Ds mu nu X decays, where the Ds meson is reconstructed in the final state K K pi. The measurement is performed in three regions in the Dalitz phase space of the Ds decay, and corrected for detection and background asymmetries. A value of asls = (0.39 +/- 0.26(stat) +/- 0.20(syst))% is found, which is the world's most precise measurement of a CP asymmetry in B meson mixing and is consistent with the Standard Model prediction. The second measurement determines the production asymmetry of Ds mesons, and probes non-perturbative QCD models. It is performed in bins of transverse momentum and pseudorapidity in the kinematic region 2.5

Date of Award	17 Oct 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Christopher Parkes (Main Supervisor) & Marco Gersabeck (Co Supervisor)