Barn (unit)

A barn is a unit of area, equal to 10^-28 m². Although not an official SI unit, it is widely used by nuclear physicists as it is considered to be "as big as a barn" compared to the typical cross sections for nuclear reactions.

External links

• IUPAC citation for this usage of "barn" (http://www.iupac.org/goldbook/B00598.pdf)
• http://www-ed.fnal.gov/painless/htmls/cross.html