Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)




Tomasz Skwarnicki


Amplitude analyses of B0 → J/ψ(1S)π−K+ and B0 → ψ(2S)π−K+ decays are presented.The data correspond to the full LHCb Run 1 and Run 2 samples, which are much larger than previously analyzed by the Belle and LHCb experiments in similar analyses. Many more exotic ψ(nS)π− states are required for a good description of the data than disclosed by the previous amplitude analyses. For the first time, significant contributions from exotic ψ(nS)K+ states are observed. The JP = 1+ Z(4200)− state, previously established only in the J/ψ(1S)π− mode, is confirmed and observed with the consistent mass and width in the ψ(2S)π− mode. However, there are also a number of inconsistencies between the exotic states required by the two data sets which point to theoretical limitations of modelling these decays as a collection of resonances decaying only to K+π−, ψ(nS)π− or ψ(nS)K+. Possible future directions in amplitude analyses of these decays are discussed.


Open Access