cross section

Measure of probability that a specific process will take place in a collision of two particles

EntityQ17128025

Also known as reaction cross-section · cross-section of interaction · cross-section

Subclass of: physical quantity
, area

Overview

From Wikipedia, the free encyclopedia · Read full article · Text CC BY-SA 4.0

In physics, the cross section is a measure related to the probability that a specific process will take place in a collision of two particles. For example, the Rutherford cross section is a measure of probability that an alpha particle will be deflected by a given angle during an interaction with an atomic nucleus. Cross section is typically denoted σ (sigma) and has dimension of area, with units of square meter or more often in barns. In a way, it can be thought of as the size of the object that the excitation must hit in order for the process to occur, but more exactly, it is a parameter of a stochastic process.

Overview

All data

28 statements · 39% with external sources · numbers in brackets are citations

Defining formula: d\sigma ={\frac {dN}{j}}
ISQ dimension: \mathsf{L}^2
Quantity symbol (LaTeX): \sigma
1
Sources
1.Stated in ISO 80000-10:2019 Quantities and units — Part 10: Atomic and nuclear physics
View statement on Wikidata ↗
a
Recommended unit of measurement: square metre
1
Sources
1.Stated in ISO 80000-10:2019 Quantities and units — Part 10: Atomic and nuclear physics
View statement on Wikidata ↗
barn
1
Sources
1.Stated in ISO 80000-10:2019 Quantities and units — Part 10: Atomic and nuclear physics
View statement on Wikidata ↗
Different from: cross-sectional area

On other databases

16 identifiers linking cross section across the web's reference databases

Data quality

statements

39%

externally sourced

Source last edited August 2, 2026. AIDB refreshes this page daily.

Suggest a fact or correction

Links

Use this data

curl https://aidb.si/api/v1/entities/Q17128025

API docs, limits & keys

Cite this page

AIDB. (2026). cross section (Q17128025). Retrieved from https://aidb.si/e/cross-section-Q17128025