title: Development and calibration of a same side kaon tagging  algorithm and measurement of the B_s^0 – B_s^0 bar oscillation frequency Δm_s at the LHCb experiment
creator: Krocker, Georg Alexander
subject: ddc-530
subject: 530 Physics
description: This thesis presents a so called same side kaon tagging algorithm, which is used in the determination of the production flavour of B_s^0 mesons. The measurement of the B_s^0 – B_s^0 bar oscillation frequency ΔDelta ms in the decay B_s^0 -> D_s^- π^+ is used to optimise and calibrate this algorithm. The presented studies are performed on a data set  corresponding to an integrated luminosity of L = 1.0 fb^-1 collected by the LHCb experiment in 2011. The same side kaon tagging algorithm, based on multivariant classifiers, is developed, calibrated and tested using a sample of about 26,000 reconstructed B_s^0 -> D_s^- π^+ decays. An effective tagging power of ε_eff = ε_tag(1 - 2ω)^2 = 2.42 +- 0.39% is achieved. Combining the same side kaon tagging algorithm with additional flavour tagging algorithms results in a combined tagging performance of ε_eff = ε_tag(1 - 2ω)^2 = 5.13 +- 0.54%. With this combination, the B_s^0 – B_s^0 bar oscillation frequency is measured to be Δm_s = 17.745 +- 0.022 (stat.) +- 0.006 (syst.) ps^-1, which is the most precise measurement to date.
date: 2013
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/15769/1/KrockerThesis.pdf
identifier: DOI:10.11588/heidok.00015769
identifier: urn:nbn:de:bsz:16-heidok-157693
identifier:   Krocker, Georg Alexander  (2013) Development and calibration of a same side kaon tagging algorithm and measurement of the B_s^0 – B_s^0 bar oscillation frequency Δm_s at the LHCb experiment.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/15769/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng