Understanding the impact of non-local contributions to  B ̄⁰ →K ̄^*0 μμ transitions

Abstract

The impact of the non-local contributions to B ̄⁰ → K ̄^∗0μ+μ− decays has been assessed through creating a framework suitable to perform a five dimensional, unbinned, maximum likelihood fit to the data collected by the LHCb experiment. Both B ̄⁰ and B⁰ decays are treated equally in this analysis, thus providing a sample rich in B ̄⁰(B⁰) → K ̄^∗0(K^∗0)μ+μ− candidates. The data analysed corresponds to the full Run 1 dataset which equates to an integrated luminosity of 3 fb⁻¹, and the 2016 dataset from Run 2 that amounts to an integrated luminosity of 1.67 fb⁻¹.
The model considers all possible hadronic contributions that contribute to B ̄⁰ → K ̄^∗0μ+μ− decays, in the invariant dilepton mass squared (q²) region of 1.0 < q² < 18.0 GeV²/c⁴. No previous analyses have been published that determine the impact of the non-local contributions in B ̄⁰ → K ̄^∗0μ+μ− decays. Therefore, for the first time, the analysis presented in this thesis tries to understand these contributions.
Recent results published from LHCb reveal anomalous results seen in b → sl+l− transitions. Possible explanations include New Physics, at the TeV scale, or hadronic resonances interfering with the penguin component and causing a sizeable effect that appears like New Physics. This analysis through a fit to the data will determine the latter, demonstrating how the effects seen could be due to our lack of understanding of the non-local contributions.

Date of Award	23 Jan 2020
Original language	English
Awarding Institution	The University of Bristol
Supervisor	Konstantinos A. Petridis (Supervisor)