# Isospin conservation and pi-meson

1. May 6, 2010

### MathematicalPhysicist

I am given this next question:
Show that the new resonance Z+[4430] which is too heavy to consist entirely of d and u quarks cannot be a meson (which constitues from a quark and an anti quark).

I am given that it's decay in a strong interaction to particles $$\psi',\pi^+$$
And I know that the first has isospin I=0 and the second I=1, and in strong interaction I is conserved, i.e Z+[4430] should have I=1 only, so if it were a meson it can only be composed of u and anti d or anti u and d, but from because of the remark it's not possible.

Am I correct here?