%0 Generic
%A Grabowski, Jascha
%C Heidelberg
%D 2022
%F heidok:31115
%R 10.11588/heidok.00031115
%T Amplitude Analysis of the Decay B0s→ψ(2S)π+π- with the LHCb Experiment
%U https://archiv.ub.uni-heidelberg.de/volltextserver/31115/
%X This thesis presents the first analysis of the hadronic amplitudes in the decay B0s → ψ(2S)π+π− . The pions originate from the ss quark system of the weak B0s decay, which removes contributions from Isospin 1 resonances. This allows to test a novel dispersive approach for a process-independent description of the dipion isoscalar S-wave. Additionally, the tetraquark candidate Z(4430)− is known to contribute to ψ(2S)π−  in B0→ ψ(2S)K+π− . An observation of this state in the ψ(2S)π± systems in B0s→ψ(2S) π+π− would give insights into its production mechanism and internal structure. The search for this state among the intermediate hadronic states of the B0s→ ψ(2S)π+π− decay is thus also part of the thesis. Using proton-proton collision data collected by the LHCb experiment in the years 2011, 2012, 2015-2018 at 7, 8, and 13 TeV corresponding to integrated luminosities of 1, 2, and 5 fb^-1 , the fit fractions of S-wave and the individual f_2 states are determined and the process-independence of the S-wave parametrisation is shown. Furthermore, a search for the exotic tetraquark candidate Z(4430)± in B0s → Z(4430)±π∓ with Z(4430)± →ψ(2S)π± is performed. No significant exotic contribution is measured and an upper limit on the fraction of decays proceeding via Z(4430)± is found to be F (Z) < 1.0 % at 95 % confidence level.