Optimized estimation of energy loss rate for charged particles from energy deposit measurements in tracking detectors

The estimation of energy loss rate d E / d x for charged particles in tracking detectors using energy deposit measurements is studied. The truncated mean method is generalized to the weighted mean of the measurements. The weights are optimized for better particle separation in the energy loss rate variable, for arithmetic and geometric means, using a detailed simulation. The obtained weights are rather independent of particle momentum and track segment length. Their values are connected to the form of the corresponding energy deposit distribution, allowing for a simple universal description as a function of the number of measured track segments. While for semiconductor detectors the weighted mean estimator may be further improved with maximum likelihood methods, for gaseous detectors the (0%,55%) truncation already gives excellent results.