  We consider the ratio between the double and single Higgs production cross
sections and examine the prospect of measuring the trilinear Higgs
self-coupling using this observable. Such a ratio has a reduced theoretical
(scale) uncertainty than the double Higgs cross section. We find that with
600/fb, the 14 TeV LHC can constraint the trilinear Higgs self coupling to be
positive, and with 3000/fb one could measure it with a +30 % {-20 %}) accuracy.
