# Quark decay

1. Aug 21, 2014

### HMPARTICLE

1. The problem statement, all variables and given/known data

One of the following equations represent a possible decay of the K + kaon.
K+ → π+ + π0
K+ → μ+ + νμ
State, with a reason, which one of these decays is not possible.

3. The attempt at a solution

At first i thought the first decay was not possible, however, i recently learned that strange quarks decay in to other quarks ( I am aware that a +kaon is made up of and up quark and anti-strange quark). I say other quarks because I'm not sure which either a strange quark or anti-strange quark decay into. After some further calculations i realised that the second decay is not possible as lepton numbers are not conserved.

So request is, could i have some information on strange quark decay at an A level standard. For some reason i can't find anything in my text book.

2. Aug 21, 2014

### Orodruin

Staff Emeritus
Both of the decays are possible. As long as the νμ is a neutrino and not an anti-neutrino, it does not break lepton number.

The branching ratio to the first decay is around 21% and to the second around 64%. See http://pdg.lbl.gov/2013/listings/rpp2013-list-K-plus-minus.pdf