The BABAR Collaboration is a high energy physics experiment located at the Stanford Linear Accelerator Center. The primary goal of the experiment is to study charge and parity violation in the B-meson sector, however the copious production of B mesons decaying to other final states allows for a wide-ranging physics program. In particular, one can access the charmonium system via colour-suppressed b → c decays of the type B → ccK.This thesis presents a study of B → ccγK decays where cc includes J/ψ and ψ(2S), and K includes K ± , K 0 S and K * (892). The particular emphasis is on a search for the radiative decays X(3872) → J/ψ γ and X(3872) → ψ(2S)γ. The X(3872) state is a recently-discovered resonance of undetermined quark composition, speculatively a conventional charmonium state or exotic four-quark di-meson molecule. This research is also sensitive to the well-known radiative charmonium decays B → χ c1,2 K, which are used as verification for the analysis technique.This dissertation sets the best B → χ c1 K branching fraction measurements to date, and sees the first evidence for factorization-suppressed B 0 → χ c2 K * 0 decay at a level of 3.6σ. It also provides evidence for X(3872) → J/ψγ and X(3872) → ψ(2S)γ with 3.6σ and 3.3σ significance, respectively.The product of branching fractions B(B ± → X(3872)K ± ) · B(X(3872) → J/ψγ) = (2.8 ± 0.8(stat.) ± 0.2(syst.)) × 10 −6 and B(B ± → X(3872)K ± ) · B(X(3872) → ψ(2S)γ) = (9.5 ± 2.7(stat.) ± 0.9(syst.)) × 10 −6 are measured.These results improve upon previous X(3872) → J/ψ γ measurements, and represent the first evidence for X(3872) → ψ(2S)γ.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.