In
scattering theory
In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiat ...
and
accelerator physics
Accelerator physics is a branch of applied physics, concerned with designing, building and operating particle accelerators. As such, it can be described as the study of motion, manipulation and observation of relativistic charged particle beams ...
, luminosity (''L'') is the ratio of the number of
events detected (''dN'') in a certain period of time (''dt'') to the
cross-section
Cross section may refer to:
* Cross section (geometry)
** Cross-sectional views in architecture and engineering 3D
* Cross section (geology)
* Cross section (electronics)
* Radar cross section, measure of detectability
* Cross section (physics)
...
(''σ''):
[
]
:
It has the dimensions of events on time on area, and is usually expressed in the
cgs units of
cm−2·
s−1 or the
non-SI units of
b−1·s
−1. In practice, ''L'' is dependent on the
particle beam parameters, such as beam width and particle flow rate, as well as the target properties, such as target size and density.
[
A related quantity is integrated luminosity (''L''int), which is the ]integral
In mathematics, an integral is the continuous analog of a Summation, sum, which is used to calculate area, areas, volume, volumes, and their generalizations. Integration, the process of computing an integral, is one of the two fundamental oper ...
of the luminosity with respect to time:[
:
The luminosity and integrated luminosity are useful values to characterize the performance of a ]particle accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies to contain them in well-defined particle beam, beams. Small accelerators are used for fundamental ...
. In particular, all collider experiments aim to maximize their integrated luminosities, as the higher the integrated luminosity, the more data is available to analyze.[
]
Examples of collider luminosity
Here are a few examples of the luminosity of certain accelerators.[
]
References
Accelerator physics
Scattering theory