Comment on "New Experimental Limit for the Electric Dipole Moment of the Neutron"

TL;DR

This paper critiques a recent neutron electric dipole moment measurement, highlighting potential systematic errors in the older experiment and arguing against combining results, advocating for reporting separate limits instead.

Contribution

It reveals possible systematic errors in previous measurements and challenges the validity of averaging experimental results in neutron EDM studies.

Findings

Old experiment's systematic error may be four times larger than the reported limit.

Averaging results from experiments with different statistical accuracies can be statistically invalid.

Separate reporting of independent limits is more appropriate than combined results.

Abstract

A new limit for the neutron electric dipole moment has been recently reported. This new limit is obtained by combining the result from a previous experiment with the result from a more recent experiment that has much worse statistical accuracy. We show that the old result has a systematic error possibly four times greater than the new limit, and under the circumstances, averaging of the old and new results is statistically invalid. The conclusion is that it would be more appropriate to quote two independent but mutually supportive limits as obtained from each experiment separately.