Types of Interaction 


Leptons and hadrons 




Only for hadrons 

   The decay of hadrons by the weak interaction can be viewed as a process of decay of their constituent quarks. There is a pattern of these quark decays: a quark of charge +2/3 ( u,c,t) is always transformed to a quark of charge -1/3 (d,s,b) and vice versa. This is because the transformation proceeds by the exchange of charged W bosons, which must change the charge by one unit. The general pattern is that the quarks will decay to the most massive quark possible, leading the the pattern 

t -> b -> c -> s -> u <-> d 

Definition provided by Hyperphysics 


The New Conservation Law.

     The number of strange (and top, bottom and charmed) quarks in a particle must be conserved.  The conservation law is refereed to as strangeness because the strange quark is the third (and strangest at the time) quark discovered. 

     During the electromagnetic and nuclear strong interactions the number of these second and third generation quarks must be conserved. 

      When a quark undergoes a Nuclear weak interaction the type of quarks in a particle changes therefor violating the strangeness of the particle. 


Strong or Color

Only for hadrons 

   Color confinement, often simply called confinement, is the phenomenon that color charged quarks cannot be isolated singularly, and therefore cannot be directly observed. Quarks, by default, clump together to form groups, or hadrons. The two types of hadrons are the mesons (one quark, one anti-quark) and the baryons (three quarks). The constituent quarks in a group cannot be separated from their parent hadron, and this is why quarks can never be studied or observed in any more direct way than at a hadron level.

 Definition provided by Wikipedia

Color Change 

   A quark can change its color if it undergoes a Nuclear Strong Interaction. The quark emits a gluon that changes  its color, the gluon is absorbed by a neighboring quark changes its color, and emits its own gluon.



Leptons and Hadrons