Hello all ! I was trying to solve the following problem : you have a particle with spin J=1 and unknown parity that decays into 2 indentical particals of spin = 1/2(adsbygoogle = window.adsbygoogle || []).push({});

We want to know how much the angular momentum of the final state is and also the final total spin.

Now, my reasonment was the following.

Stot_final = either 0 or 1 since it is the vector sum of the spin of both identical final particles.

Knowing that |L-S|<=J<= L+S we have to cases but I assumed that J=1 is conserved in the decay but it wasn't told so ...

we would have

for S=0 => L= 1

for S=1 => L= (0,1,2)

knowing that the final particles are indentical they must have a antisymmetric wave function due to Fermi Dirac...and so L must be odd . => L=1

but we still have to cases (S,L)= (0,1) or (1,1) if J=1 was to be conserved I'd say th only possible is (0,1) but the solutions say the only possibile solution knowing that J=1 is (1,1) ..

Conclusion, I don't know where I'm mistaking !

Any help would be appreciated ! Maybe I shouldn't assume that J was conserved...

Thanks in advance !

Erwin

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# Homework Help: Decay and parity

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