Bottomness

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Flavour in particle physics
Flavour quantum numbers:

Related quantum numbers:


Combinations:


Flavour mixing

In physics, bottomness (symbol B[citation needed]) also called beauty, is a flavour quantum number reflecting the difference between the number of bottom antiquarks (nb) and the number of bottom quarks (nb) that are present in a particle:

 B^\prime = -(n_b - n_{\bar b})

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 = −13).

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 \Delta B^\prime = \plusmn 1.

This term is rarely used. Most physicists simply refer to "the number of bottom quarks" and "the number of bottom antiquarks".

Further reading[edit]