Speakers
Description
The Belle II experiment at SuperKEKB is rapidly approaching its data taking phase, where it will be used to perform precision measurements of SM and new physics processes with unprecedented accuracy. At the same time, the Belle dataset (~1ab^{-1}) still presents rich possibilities for physics analyses, which can now also be performed within the Belle II Analysis Software Framework (basf2). In both of these cases, high precision reconstruction of particle observables is paramount.
Decay chains in particle physics experiments are typically reconstructed vertex by vertex, starting with final state particles and ending with the head of the decay tree. However, this means each vertex fit is blind to upstream information which could potentially improve the fit resolution.
An alternate approach, which was used with success in BaBar, involves using a least square approach, based on a Kalman filter, to extract all parameters of the decay chain simultaneously. This method is especially useful in the reconstruction of neutral or missing particles and provides access to the full covariance matrix of the decay. It is being implemented in basf2 and will be presented along with the outlook for future physics analyses.
