Quantum numbers.

Quantum numbers;

In case of elementary particles, while considering reactions, we must consider various parameters. One of the major parameter is quantum numbers. 

Baryon and lepton numbers

A set of quantum numbers is used to characterise baryons and three families of leptons.

Baryon and lepton numbers.

 

The significance of these numbers is that in any kind of reaction the total baryon numbers (B) and lepton numbers are conserved.

Baryon and lepton quantum numbers are conserved.

Strangeness number (S)

Gellmann and Nishijina introduced a new quantum number called strangeness quantum number. Strangeness number is assigned to strange particles, which are named due to their strange behaviour i.e they are produced via strong interaction or electromagnetic interaction, but they decay via weak interaction. Another fact about these particles is that they are always produced in pairs. The assignment of strangeness number to particle is shown in Table below.

Strangeness number of hadrons.

The antiparticles have the S value negative of shown above.

Strangeness number (S) are conserved in all process mediated by strong and electromagnetic interactions. Example in proton - proton collision.

Proton Proton Collision.