Definitions
from Wiktionary, Creative Commons Attribution/ShareAlike License
 n. A unit of area equal to a billionth of a millionth (1015) of a barn
Etymologies
Sorry, no etymologies found.
Examples

In these years, the Tevatron marched on, reaching its first inverse femtobarn by mid 2005, then setting new records almost routinely in the following years.

(Recall that they will stop the collider at the end of 2011 or when they reach 1/femtobarn, whatever comes first.)

If they increase the luninosity by a factor of 30, they will reach 1/femtobarn per year  which is enough to fulfill the realistic plan of 1/femtobarn before the end of 2011.

It will work to accumulate one inverse femtobarn of collisions and stop, but not later than at the end of 2011.

An inverse femtobarn at the LHC pushes the discovery range up to

With the amount of data expected, called one inverse femtobarn by physicists, the combined analysis of ATLAS and CMS will be able to explore a wide mass range, and there's even a chance of discovery if the Higgs has a mass near 160 GeV.

With the amount of data expected, referred to as one inverse femtobarn, the experiments should be well placed to make inroads in to new territory, with the possibility of significant discoveries.

An inverse femtobarn at the LHC pushes the discovery range up to 800 GeV.

Well, they have to improve the luminosity by a factor of 1,000 to collect one inverse femtobarn by the end of 2011.

By next year, collisions will be occurring  if all continues to go well  at a rate producing what physicists call one "inverse femtobarn," best described as a colossal amount, of information for analysts to ponder.
qms commented on the word femtobarn
The boffins with patient precision
Examine each tiny collision
And don't give a darn 
Not one femtobarn 
For ignorant cries of derision.
October 14, 2016