Measurements of the local and non-local contributions in B±→K±μ±μ decays using LHCb data

  • Lakshan Madhan Mohan

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)


In the study of the decay of B mesons, the observed deviations from standard model predictions could potentially be explained by underestimated non-local hadronic intermediate states. To answer this question, the contribution of local and non-local contributions to B±→K±μ±μ decays are measured by analysing the invariant dimuon mass distribution in the range: 300 < mμμ < 4700 MeV/ c2 (0.09 < q2 < 22.09 GeV2/c4 ). The analysis uses pp collision data collected by the LHCb experiment between 2011 and 2018 corresponding to an integrated luminosity of 9 fb−1. The non-local contributions are modelled using hadronic dispersion relations including a description of intermediate one-particle and two-particle states which scatter to a pair of muons. The largest one-particle states interfering with the local contribution are J/ψ and ψ(2S) and the two-particle states described are DD, D D and DD. The interference from J/ψ is observed to be small while a large component of the two-particle states, along with the ψ(2S), is observed to destructively interfere with the local contribution. The effect of this interference on the vector current ( C9 ) and axial-vector current ( C10 ) Wilson coefficients, which encode heavy standard model and beyond standard model physics, are discussed. The branching fractions of the one-particle and two-particle states are also measured.
Date of Award27 Sept 2022
Original languageEnglish
Awarding Institution
  • University of Bristol
SupervisorKonstantinos A. Petridis (Supervisor) & Jonas H Rademacker (Supervisor)


  • particle physics
  • High Energy Physics
  • Flavour Physics
  • Rare Decays

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