Analysis of rare B meson decays at the Japanese B meson factory experiment Belle exploiting new neural full reconstruction algorithms

在B工厂，电子和正电子的碰撞能量几乎总是只产生一对B介子。日本加速器KEKB的贝尔实验保持着重建B介子的世界纪录，该实验使用的是过去10年收集的数据集。到目前为止，根据小林和Maskawa的理论，对这些数据的许多分析已经证实了粒子物理的标准模型具有很高的准确性，包括衰减率、粒子反粒子振荡和对CP对称性的破坏，他们在2008年获得了诺贝尔奖。然而，如果测量精度进一步提高，标准模型的许多流行扩展，如超对称性，可能会显现出来。申请者基于贝叶斯统计和71个神经网络系统，开发了一个新的分层重建方案，包括1042个B衰变通道，以最大化一个完全重建的B介子的数据集。应用这个软件，我们可以将依赖于完全重建的分析的有效光度增加一倍以上，这相当于多年的额外数据获取。通过这个建议，我们希望确保我们可以在物理输出方面利用我们的软件创新。我们建议对稀有的B衰变进行一些数据分析，特别是从完全重建B介子中获益，这只可能在B工厂进行，因此是对不久的将来将进行的其他实验的补充，例如包括LHCb在内的LHC。

At B factories electrons and positrons are collided at an energy where almost always only a pair of B mesons is produced. The BELLE experiment at the Japanese accelerator KEKB holds the world record in reconstructed B mesons with a data set collected in the last 10 years. So far many analyses of this data have confirmed the Standard Model of Particle Physics to a large accuracy, including decay rates, particle antiparticle oscillations, and violations of the CP symmetry in accordance with the theory of Kobayashi and Maskawa, who were honoured in 2008 with the Nobel Prize. However, many popular extensions of the Standard Model, e.g. Supersymmetry, could show up if the measurements precision is further improved.The applicants have developed a new hierarchical reconstruction scheme of 1042 B decay channels, based on Bayesian statistics and a system of 71 neural networks, to maximise the data set with one fully reconstructed B meson. Applying this software we could more than double the effective luminosity for analyses relying on full reconstruction, corresponding to many years of additional data taking.With this proposal we wish to make sure that we can exploit our software innovation in terms of physics output. We propose to perform several data analyses on rare B decay especially profiting from the full reconstruction of B mesons, which is only possible at B factories and therefore complementary to other experiments to be performed in the near future, such as LHC including LHCb.