Measurement of the Raw Asymmetry Ratio in the Decay Λ 0 b → Λ 0 (→ pπ−)J/ψ (→ e +e −)

De Mare, Ludovica (2024) Measurement of the Raw Asymmetry Ratio in the Decay Λ 0 b → Λ 0 (→ pπ−)J/ψ (→ e +e −). Bachelor's Thesis, Physics.

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Abstract

It is essential to confirm that no CP violation (CPV) is observed in the Λ 0 b → Λ 0 (→ pπ−)J/ψ (→ e +e −) decay in order to use it as a normalization channel for testing CPV in the Λ 0 b → e +e −Λ 0 decay. In this thesis, an analysis is conducted on LHC Run 2 data (years 2016–2018), corresponding to an integrated luminosity of 5.57 fb−1 , collected by the LHCb experiment from proton-proton collisions at √ s = 13 TeV. From the data, events compatible with the signal decay are selected and a suppression of the background process B0 → J/ψK0 s based on kinematic properties is applied. In order to test for detection asymmetries, events taken at the two different polarities of the LHCb dipole magnet are analyzed, separately. Signal yields of Λ 0 b and Λ0 b along with the raw asymmetry ratio, are extracted through binned fits for each sample and the combined dataset. No detection asymmetry is observed and a raw asymmetry ratio of Araw = 0.029 ± 0.032 is measured for the combined dataset, leading to the conclusion that, in this study, no CP violation is observed in the decay.

Item Type:	Thesis (Bachelor's Thesis)
Supervisor name:	Perrevoort, A. and Hoekstra, S.
Degree programme:	Physics
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	17 Oct 2024 07:22
Last Modified:	17 Oct 2024 07:22
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/34324

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