False peaks and resonance narrowing due to variable resolution

Circumstances are described in which a variable resolution (typically present in counter experiments) may distort resonance shapes, so that they appear to be narrower, or when false peaks may be created in otherwise flat distributions. The effect is illustrated with simplified examples, and with the CERN missing-mass spectrometer of 1966-67. Although the effect is present in the CERN experiment, it is not found to be adequate to account for the narrowness of the observed peaks. (4 refs).