Weighing Neutrinos with Galaxy Cluster Surveys
  Large future galaxy cluster surveys, combined with cosmic microwave background observations, can achieve a high sensitivity to the masses of cosmologically important neutrinos. We show that a weak lensing selected sample of ~100,000 clusters could tighten the current upper bound on the sum of masses of neutrino species by an order of magnitude, to a level of 0.03 eV. Since this statistical sensitivity is below the best existing lower limit on the mass of at least one neutrino species, a future detection is likely, provided that systematic errors can be controlled to a similar level. 
Sheng Wang (Columbia; Brookhaven), Zoltan Haiman (Columbia), Wayne Hu   (KICP, U. Chicago), Justin Khoury (MIT), Morgan May ...