Dalitz Plot Analysis of B0 → K+ π− π0 Decays at the Belle II Experiment

Sumitted to PubDB: 2024-11-07

Category: Phd Thesis, Visibility: Public

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Authors Thomas Kuhr, Hans-Günther Moser, Markus Reif
Date Jan. 1, 2024
Belle II Number BELLE2-PTHESIS-2024-020
Abstract This thesis reports a determination of the branching fraction (B) and CP-violating charge asymmetry (ACP ) of the three-body decay B0 → K+ π− π0 at the Belle II experiment. In addition to the inclusive B and ACP , i.e. for B0 → K+ π− π0 decays, we measure B and ACP exclusively for individual two-body resonances appearing in the K+ π− π0 system. To this end, we employ a model dependent Dalitz plot analysis, including the seven dominant intermediate resonances and a non-resonant contribution. The analyzed data were recorded between 2019 and 2022 and correspond to an integrated luminosity of 362 fb−1 produced in e+ e− collisions at the Υ (4S) resonance by the SuperKEKB collider containing 387 × 106 pairs of bottom-antibottom mesons. The analysis is developed on simulated data and control mode data solely. The branching fractions and CP-asymmetries are extracted in a four-dimensional extended maximum likelihood fit. As the analysis is still under Belle II internal review, we blind central values and state uncertainties only. We measure the branching fraction and CP-violating charge asymmetry inclusively as well as exclusively for the channels B0 → K∗(892)+ π− , B0 → K∗(892)0 π0 , B0 → ρ(770)− K+ , B0 →(Kπ)∗+ π-, B0 → (Kπ)*0 π0, B0 → ρ(1450)- K+, B0 → ρ(1700)- K+ and B0 → K+ π- π0 non-resonant. This thesis presents the first model dependent Dalitz plot analysis at Belle II. We achieve uncertainties on par with known determinations. The B0 → K∗(892) π modes will serve as inputs for a sum rule based on isospin to probe the Standard Model.
Conference Garching

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