Neutron Compton scattering probes properties of matter at time scales of th
e order of 10(-16)-10(-15) s. Very strong anomalies in the cross-sections f
or protons were observed for scattering on NbHx and NbHxDy. The effective p
roton cross-section was found to vary with the time of observation (first u
sed as a parameter in the present experiments) being reduced by 30% at time
s around 10(-16) s but reaching its conventional value for times larger tha
n 2.10(-15) s. No conventional explanation for this anomaly (which indicate
s some kind of very short-lived correlations) is known. A tentative explana
tion is that during such short time intervals, nearby protons are quantum c
orrelated (even at ambient temperatures) in such a manner that their neutro
n cross-sections are modified.