sigma

sigma The eighteenth letter of the Classical Greek|Classical and Modern Greek, the twentieth letter of Old Greek|Old and Ancient Greek|Ancient.
http://www.ancient.eu/article/149/ "Herodotus: On The Customs of the Persians", I.139:
*Their names, which are expressive of some bodily or mental excellence, all end with the same letter---the letter which is called San by the Dorians, and Sigma by the Ionians.
puhekieltä The symbol Σ, used to indicate summation of a set or series.
puhekieltä The symbol σ, used to indicate one standard deviation from the mean, particularly in a normal distribution.
2011, Paul Rincon, (bbc.co.uk) http://www.bbc.co.uk/news/science-environment-16158374 LHC: Higgs boson may have been glimpsed'''

None of the spikes seen by the experiments is at much more than the "two sigma" level of certainty.A level of "five sigma" is required to claim a discovery, meaning there is less than a one in a million chance the data spike is down to a statistical fluke.