Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.
Concept
Particle decay
Summary
In particle physics, particle decay is the spontaneous process of one unstable subatomic particle transforming into multiple other particles. The particles created in this process (the final state) must each be less massive than the original, although the total invariant mass of the system must be conserved. A particle is unstable if there is at least one allowed final state that it can decay into. Unstable particles will often have multiple ways of decaying, each with its own associated probability. Decays are mediated by one or several fundamental forces. The particles in the final state may themselves be unstable and subject to further decay.
The term is typically distinct from radioactive decay, in which an unstable atomic nucleus is transformed into a lighter nucleus accompanied by the emission of particles or radiation, although the two are conceptually similar and are often described using the same terminology.
Particle decay is a Poisson process, and hence the probability that a particle survives for time t before decaying (the survival function) is given by an exponential distribution whose time constant depends on the particle's velocity:
where
is the mean lifetime of the particle (when at rest), and
is the Lorentz factor of the particle.
All data are from the Particle Data Group.
{| class=wikitable style="text-align: center;"
!Type
!Name
!Symbol
!Mass (MeV)
!Mean lifetime
|-
|rowspan="3" | Lepton
|Electron / Positron
|
|0.511
|
|-
|Muon / Antimuon
|
|105.7
|
|-
|Tau lepton / Antitau
|
|1777
|
|-
|rowspan="2" | Meson
|Neutral Pion
|
|135
|
|-
|Charged Pion
|
|139.6
|
|-
|rowspan="2" | Baryon
|Proton / Antiproton
|
|938.2
|
|-
|Neutron / Antineutron
|
|939.6
|
|-
|rowspan="2" | Boson
|W boson
|
|80400
|
|-
|Z boson
|
|91000
|
|}
This section uses natural units, where
The lifetime of a particle is given by the inverse of its decay rate, , the probability per unit time that the particle will decay.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related publications (3)
Weighing wimps with kinks at colliders: invisible particle mass measurements from endpoints
We consider the application of endpoint techniques to the problem of mass determination for new particles produced at a hadron collider, where these particles decay to an invisible particle of unknown
2008Transverse observables and mass determination at hadron colliders
I consider the two-body decay of a particle at a hadron collider into a visible and an invisible particle, generalizing W -> ev, where the masses of the decaying particle and the invisible decay parti
2008