Misplaced Pages

This is an old revision of this page, as edited by Krovisser (talk | contribs) at 00:52, 30 January 2006 (math). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

In particle physics, the mathematical combination of a particle's energy and its momentum to give a value for the mass of the particle at rest. The invariant mass is the same for all frames of reference (see Special Relativity).

The invariant mass of a system of decay particles is related to the rest mass of the original particle by the following equation:

${\displaystyle {\mbox{W}}^{2}{\mbox{c}}^{4}=(\Sigma {\mbox{E}})^{2}-(\Sigma {\mbox{pc}})^{2}}$

Where:

${\displaystyle W}$ is the invariant mass of the system of particles

${\displaystyle \Sigma E}$ is the sum of the energies of the particles

${\displaystyle \Sigma pc}$ is the vector sum of the momenta of the particles (includes both magnitude and direction of the momenta) times the speed of light, ${\displaystyle c}$

See also

• Relativistic mass
• Invariant_(physics)

• Relativity
• Mass