There are different sources of errors, usually categorized as statistical and systematic. The statistical error will decrease with higher statistics but the sys

There are different sources of errors, usually categorized as statistical and systematic. The statistical error will decrease with higher statistics but the systematic error will not. An example for a systematic error would be the error of the energy calibration. In the paper they claim for one of the measured ratios R(D)=0.440+-0.058 (statistical) +- 0.042 (systematic) and the result would at best get about sqrt(2) as good if you would get rid of the statistical error. (Assuming the errors are uncorrelated they combine as the root of the squares).