Luminosity (scattering theory)
In scattering theory and accelerator physics, luminosity (L) is the ratio of the number of events detected (N) in a certain time (t) to the interaction cross-section (σ):[1]
It has the dimensions of events per time per 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.[1]
A related quantity is integrated luminosity (Lint), which is the integral of the luminosity with respect to time:[1]
The luminosity and integrated luminosity are useful values to characterize the performance of a particle accelerator. In particular, all collider experiments aim to maximize their integrated luminosities, as the higher the integrated luminosity, the more data is available to analyze.[1]
Examples of collider luminosity
Here are a few examples of the luminosity of certain accelerators.[1]
| Collider | Interaction | L (cm−2·s−1) |
|---|---|---|
| SPS | p + p | 6.0×1030 |
| Tevatron[2] | p + p | 4.0×1032 |
| HERA | proton + e+ | 4.0×1031 |
| LHC[3] | p + p | 1.5×1034 |
| LEP | e− + e+ | 1.0×1032 |
| PEP | e− + e+ | 3.0×1033 |
| KEKB[4] | e− + e+ | 2.1×1034 |
References
- ^ a b c d e Herr, W.; Muratori, B. (2006). "Concept of luminosity". In Brandt, D. (ed.). CERN Accelerator School: Intermediate Course on Accelerator Physics, Zeuthen, Germany, 15-26 Sep 2003 (PDF). CERN. pp. 361–378. doi:10.5170/CERN-2006-002. ISBN 978-92-9083-267-6.
- ^ Tevatron sets new initial luminosity records, Fermilab Today news archive
- ^ LHC Performance plots
- ^ Tetsuo Abe et al.: Achievements of KEKB. In: Prog. Theor. Exp. Phys. 03A001, 2013, pp. 1–18, doi:10.1093/ptep/pts102.