Difference between revisions of "Cross section"
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| β | The '''cross section''' for a given process is a measure for the rate of interactions that originate from the process that can be quoted independently of the experimental set-up of the scattering experiment itself. In a hypothetical experiment in which a flux of particles ''F'' (particles per | + | The '''cross section''' for a given process is a measure for the rate of interactions that originate from the process that can be quoted independently of the experimental set-up of the scattering experiment itself. In a hypothetical experiment in which a flux of particles ''F'' (incident particles per unit area per unit time) scatter at a rate ''R'' (scattered particles per unit time), the cross section is π = ''R''/''F''. |
Cross sections are measured in units of area, where the special unit ''barn'' (b) is used with prefixes. A barn is 10<sup>β28</sup> m<sup>2</sup> (100 fm<sup>2</sup>). Cross sections at the [[LHC]] can range from hundreds of millibarns (the total cross section of proton-proton collisions) down to fb or smaller for rare processes that are still considered to be measurable. | Cross sections are measured in units of area, where the special unit ''barn'' (b) is used with prefixes. A barn is 10<sup>β28</sup> m<sup>2</sup> (100 fm<sup>2</sup>). Cross sections at the [[LHC]] can range from hundreds of millibarns (the total cross section of proton-proton collisions) down to fb or smaller for rare processes that are still considered to be measurable. | ||
Revision as of 22:00, 6 April 2017
The cross section for a given process is a measure for the rate of interactions that originate from the process that can be quoted independently of the experimental set-up of the scattering experiment itself. In a hypothetical experiment in which a flux of particles F (incident particles per unit area per unit time) scatter at a rate R (scattered particles per unit time), the cross section is π = R/F.
Cross sections are measured in units of area, where the special unit barn (b) is used with prefixes. A barn is 10β28 m2 (100 fm2). Cross sections at the LHC can range from hundreds of millibarns (the total cross section of proton-proton collisions) down to fb or smaller for rare processes that are still considered to be measurable.
In calculations using natural units (with Δ§=c=1) area has dimensions of 1/energy-squared, so units of GeV-2. The conversion is 1 GeV-2 = 0.389 mb.
