Data Analysis Techniques for High Precision Measurement of Muon Decay
Parameters. Konstantin Olchanski TRIUMF - Konstantin Olchanski TRIUMF
Data Analysis Techniques for High Precision Measurement of Muon Decay
Parameters. The TRIUMF Weak Interaction Symmetry Test (TWIST) is
investigating the space-time structure of the charged-current weak
interaction. We look for deviations from the predictions of the "V-A"
submodel of the Standard Model in the dominant decay mode of the muon,
the purely leptonic decay mu+ -> e+ nu nubar. By improving the
world-best measurements of the muon decay by a factor of 10, we hope to
open (or close) the window on physics possibilities beyond the Standard
Model. TWIST is a systematics-dominated experiment. We have developed
techniques for using special data runs and special simulations to
measure the impact of systematic effects on the overall error, rank the
effects by importance, and to eliminate some effects as sources of
systematic error. TWIST uses a system of very low mass planar wire
chambers. Still, multiple Coulomb scattering and energy loss effects are
significant and require careful handling. We have adopted the kink
method (G.Lutz, etc) for handling multiple scattering and perform a
self-consistent positron energy scale calibration to handle energy loss.
In any high-precision experiment, it's important to minimize the
potential for subjective bias, typically through blind analysis
techniques. TWIST has developed a novel procedure utilizing public-key
cryptography to extract the muon decay parameters in a blind manner.
This talk will describe the data analysis procedures used by TWIST.