title: Measurement of the CP-violating phase phis using Bs->J/Psi Phi and Bs->J/Psi pi+pi- decays with the LHCb experiment
creator: Linn, Christian
subject: ddc-530
subject: 530 Physics
description: This thesis presents a measurement of the CP-violating phase phis, arising in the interference of Bs mixing and the amplitudes of Bs->J/Psi Phi and Bs-> J/Psi pi+pi- decays.  The phase phis is an observable with very high sensitivity for physics phenomena beyond the Stamdard Model. New, heavy particles could contribute to the mixing process and influence the measured  value of phis. As the prediction for phis is very precise, already small deviations of the measured value would be a hint for new physics effects.   The presented measurement is done with a data set corresponding to an integrated luminosity of L=1.0invfb, collected during 2011 with the LHCb experiment.  The determination of phis with Bs->J/Psi Phi decays requires a time-dependent analysis, depending also on the decay angles of the Bs to separate the CP-eigenstates of the decay.  A four-dimensional maximum likelihood fit, including as well information of the Bs production flavour, is used to determine phis from the corresponding measured time and angular distributions.  The measurement of the strong phase difference between K+K- P-wave and S-wave amplitudes,  as a function of the invariant K+K- mass, allows to resolve a twofold ambiguity (phis <-> pi - phis) in the differential Bs->J/Psi Phi decay rate. The measured value is  phis  = 0.069 +- 0.091 (stat.) +- 0.014 (syst.) rad. Performing a combined analysis of Bs->J/Psi Phi and Bs->J/Psi pi+pi- decays a value of  phis  = 0.043 +- 0.076 (stat.) +- 0.014 (syst.) rad is determined. The obtained results are in agreement with the prediction.
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/14992/1/linn_thesis.pdf
identifier: DOI:10.11588/heidok.00014992
identifier: urn:nbn:de:bsz:16-heidok-149924
identifier:   Linn, Christian  (2013) Measurement of the CP-violating phase phis using Bs->J/Psi Phi and Bs->J/Psi pi+pi- decays with the LHCb experiment.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/14992/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng