Real-time alignment of the LHCb vertex detector and observation of charmless baryonic decays B(s) --> p anti-p h+ h'-

Abstract

This thesis presents measurements of the branching fractions of the charmless baryonic decays B(s) --> p anti-p h+ h'-, where h(') denotes a kaon or a pion. Three new modes (B --> p anti-p pi+ pi-, Bs --> p anti-p K+ K- and Bs --> p anti-p K+(-) pi-(+)) are observed for the first time and evidence is found for a fourth (B --> p anti-p K+ K-). The inclusive branching fraction of B --> p anti-p K+(-) pi-(+) is measured for the first time and the upper limit is set on the branching fraction of the Bs --> p anti-p pi+ pi- decay. This represents the first observation of four-body charmless baryonic decays of a Bs meson and one of the first observations of baryonic Bs decays. The implementation of the real-time alignment of LHCb's vertex detector is also described. The novel real-time alignment and calibration strategy adopted by LHCb is essential to allow more stable data taking conditions and an optimal ``offline-quality'' reconstruction to be performed at the trigger level, ensuring more efficient trigger selections and the possibility to perform physics analyses directly on the trigger output.

Date of Award	1 Aug 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Christopher Parkes (Supervisor) & George Lafferty (Supervisor)