Question

what is symmetry in particle physics?

Answer 1

it is said after bigbang everything in universe was symmentric. equal amounts of electron and it antiparticle positrons. also called Charge parity symmentry. But today we have more matter than anitmatter due to CP violation. significant amount of baryons.

Every particle is replaced with its antiparticle. This is C-symmetry (charge symmetry);
Everything appears as if reflected in a mirror. This is P-symmetry (parity symmetry);
The direction of time is reversed. This is T-symmetry (time symmetry).
source : http://en.wikipedia.org/wiki/Symmetry_(physics)

Answer 2

hence scientists found after many experiements this symmetry is not conserved for various reasons. one of them weak particle deacy. weak decay of D- meson and K-meson. fuelling CP violation

Answer 3

*k- mesons : kaons

Answer 4

i hope this is helpful . tnx