Neutrino flight times in cosmology

If neutrinos have a small but non-zero mass, time-of-flight affects for neu trino bursts from distant sources can yield information on the large-scale geometry of the universe, the effects being proportional to integral a dt, where a is the cosmological expansion parameter. In principle absolute phys ical determinations of the Hubble constant and the acceleration parameter a re possible. Practical realization of these possibilities would depend on n eutrino masses being in a favorable range and the future development of ver y large detectors. (C) 2000 Published by Elsevier Science B.V. All rights r eserved.