A Study of B{u2192}c$\bar{c}$?K in the BaBar Experiment PDF Download

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Languages : en
Pages : 224

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Book Description
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 → c$ar{c}$K. This thesis presents a study of B →c$ar{c}$?K decays where c$ar{c}$ includes J/? and ?(2S), and K includes K±, KS0 and K*(892). The particular emphasis is on a search for the radiative decays X(3872) → J/?? and X(3872) → ?(2S)?. 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 → ?c1,2K, which are used as verification for the analysis technique. This dissertation sets the best B → ?c1K branching fraction measurements to date, and sees the first evidence for factorization-suppressed B0 → ?c2}K*0 decay at a level of 3.6?. It also provides evidence for X(3872) → J/?? and X(3872) → ?(2S)? with 3.6? and 3.3? significance, respectively. The product of branching fractions ?(B± → X(3872)K±) • ?(X(3872) → J/??) = (2.8 ± 0.8(stat.) ± 0.2(syst.)) x 10−6 and ?(B{± → X(3872)K±) → ?(X(3872) → ?(2S)?) = (9.5 ± 2.7(stat.) ± 0.9(syst.)) x 10-6 are measured. These results improve upon previous X(3872) → J/?? measurements, and represent the first evidence for X(3872) → ?(2S)?.