Solar mass split and angle

We recently explained why the squared mass splitting between neutrino mass states 1 and 2 (and the associated mixing angle theta12) were often sufficient to approximate solar electron neutrino survival fraction at Earth. We had a little more to say about it though, so prepared the pdf document below available at the link to one of my Google drives (or view in the inset below and download from there also).

Solar mass split and angle (pdf)