I was wondering if anyone could help clarify this problem I am having. Upon reading a section in a paper, I am a bit stuck as to how this value of the lower bound of the neutrino mass is reached here. I have highlighted the relevent part in the snapshot below: http://img487.imageshack.us/img487/3...inomass3fk.jpg [Broken] Is there something missing from this passage, or am I just missing something blindingly obvious? I can't seem to understand how the two squared mass differences coupled with the assumption of hierarchy lead to the quoted value! in case you're curious, the paper is: http://arxiv.org/abs/astro-ph?papernum=0407207 thank you for reading!