- #1
genloz
- 76
- 1
Homework Statement
I had a whole list of reactions and had to show whether or not they could occur... I understood most of the reasons, bar the following, but was more confused about whether or not a reaction was strong or weak... I know that if the reaction involves a lepton its weak, and if it involves a photo, it's electromag, but baryons alone don't define whether a reaction is strong or weak:
For example:
[tex]\Sigma^{-} \rightarrow n + \pi^{-}[/tex]
I understand strangeness is not conserved, but why is it a weak interaction if it only involves hadrons?
[tex]e^{+} + e^{-} \rightarrow \mu^{+} + \mu^{-}[/tex]
Why is this an electromag reaction when only leptons are involved and charge is conserved on both sides and no photons are involved? Shouldn't it be a weak?
[tex]K^{-} \rightarrow \pi^{-} + \pi^{0}[/tex]
This only involves hadrons and strangeness isn't conserved, so should this be an impossible strong reaction?
I thought weak decays only didn't conserve partity, but the answers say this is a possible weak decay, does that mean weak decays don't need to conserve strangeness either? Also why is it weak rather than strong?
[tex]\pi^{-} + p \rightarrow \Lambda^{-} + \K^{0}[/tex]
I thought this would be prevented due to lack of strangeness conservation, but it's allowed via the strong interaction, why?
Thanks very much!