How is the spin of an unstable meson or baryon measured? Can bubble chambers measure the spin of particles?
Can you just use conservation of spin to deduce it or can you not infer much this way because composite particles can carry angular momentum?
It seems to me that agnetic deflection is not viable like in a Stern-Gerlach experiment because of the short lifetime of the particles.

Kaons are spin zero particles so how can an omega baryon be created here?
Did the $K^{-}$ destroy one proton and two neutrons?
 A: First for the facts: the spin of the Ω- remained experimentally undetermined for 14 years after its discovery in 1964, which you reproduce in the photograph.
It was only fixed in 1978 by Deutschmann et al, Physics Letters B73 (1) (1978) pp 96-98,  through elaborate angular distributions of dozens of decays, not a single bubble chamber picture! s-wave, p-wave, d-wave decays have distinctive and contrasting angular distributions of the products, illustrated in standard particle physics texts--recall the contrasting spherical harmonics of different $\ell$s.
Theoretically, it was evident it had to be 3/2, as a flavor symmetric, color antisymmetric, so then spin-symmetric assemblage of fermions, sss.
Your bubble chamber picture mandates little about the spins of the respective particles. A spinless K hits a spin 1/2 proton, releases two spineless K s, and incorporates orbital angular momentum 1 into the spin 3/2 of the Ω-; in turn, it decays weakly to a spinless pion and a spin 1/2 cascade, again in a p-wave, so, "releasing" one unit of angular momentum.
