Bottomness
Flavour in particle physics |
---|
Flavour quantum numbers |
|
Related quantum numbers |
|
Combinations |
|
Flavour mixing |
![]() | This article does not cite any sources. (June 2009) |
In physics, bottomness (symbol B′ using a prime as plain B is used already for baryon number) or beauty is a flavour quantum number reflecting the difference between the number of bottom antiquarks (n
b
) and the number of bottom quarks (n
b
) that are present in a particle:
Bottom quarks have (by convention) a bottomness of −1 while bottom antiquarks have a bottomness of +1. The convention is that the flavour quantum number sign for the quark is the same as the sign of the electric charge (symbol Q) of that quark (in this case, Q = −1⁄3).
As with other flavour-related quantum numbers, bottomness is preserved under strong and electromagnetic interactions, but not under weak interactions. For first-order weak reactions, it holds that .
This term is rarely used. Most physicists simply refer to "the number of bottom quarks" and "the number of bottom antiquarks".
Further reading[]
- Anchordoqui, L.; Halzen, F. (2009). "Lessons in Particle Physics". arXiv:0906.1271 [physics.ed-ph].
- Quarks
- Flavour (particle physics)
- Particle physics stubs