NEUTRINO CLOUDS

We consider the possibility that neutrinos (but no other light fermion s) are coupled very weakly to an extremely light scalar boson. We firs t analyze the simple problem of one generation of neutrino and show th at, for ranges of parameters that are allowed by existing data, such a system can have serious consequences for the evolution of stars and c ould impact precision laboratory measurements. We discuss the extensio n to more generations and show that the general conclusion remains via ble. Finally, we note that, should such a scalar field be present, exp eriments give information about effective masses, not the masses that arise in unified held theories.