Fine Structure

Defining a Femtobarn

Less than a full sentence into Dorigo's recent article on new data from the Higgs search I realized that I needed to learn the definition of a femtobarn. Googling, I found a link to a great glossary of nuclear physics terms and their inceptions. Referring to the luminosity of a collider, a femtobarn is:
A unit of cross section equal to 10-39 cm2, more or less equivalent to the physical cross-sectional area of a typical nucleus.
And that really says something if your collider can't hit the broad side of a femtobarn. I've seen it used interchangeably between the formats "1.6/fb" or "1.6 inverse femtobarns" (perhaps I don't quite understand the purposes of the two formats, it's particularly confusing for a novice physicist though).


This is a barn, a femtobarn is 10^-39 cm^2

January 27, 2009
4:18 PM

From name

Mr Anonymous Commenter speaks the truth! I'm not quite sure how this escaped the detail police for so long. Thank you, I've updated the original post.

January 27, 2009
4:28 PM

From Nick