The neutrino ground state in a neutron star
  We address a recent claim that the stability of neutron stars implies a lower bound on the mass of the neutrino. We argue that the result obtained by some previous authors is due to an improper summation of an infrared-sensitive series and that a non-perturbative "resummation" of the series yields a finite and well-behaved result. The stability of neutron stars thus gives no lower bound on the mass of the neutrino. 
Ken Kiers and Michel H.G. Tytgat