In a particle reaction we take in account the conservation laws of mass-energy , charge , angular momentum , baryon number * and lepton number *

 

I put an asterisk on baryon and lepton number because we are still unsure if those are conserved . If protons or electrons decay this would mean that the law is incorrect.

 

 

Is the same thing applied for mesons ? 

 

I mean mesons and baryons are both hadrons so why there isnt a conservation law for mesons in particle reactions?

Edited July 17, 20196 yr by AUDI R6

8 hours ago, AUDI R6 said:

Is the same thing applied for mesons ? 

There is no separate meson number, but mesons have a baryon number of 0.

This is more about quark conservation. But quarks were not known when the baryon number was defined. 

1 hour ago, Strange said:

There is no separate meson number, but mesons have a baryon number of 0.

This is more about quark conservation. But quarks were not known when the baryon number was defined. 

And with that, color charge, I think. With three quarks you can end up with a neutral color, but with two it needs to be color + anti-color. So groups of three quarks would tend to persist, since there's no decay path to a system that isn't three quarks. No so for mesons.

But yeah, before we knew about quarks, it was a pattern that certain types of particles seemed to always be around.

This might not be a full list but just off memory the numerous conservation laws

Isospin

Spin

Charge

Flavour

Energy/momentum

Lepton number

Parity

Barion number

Edited July 17, 20196 yr by Mordred