Question

4. (5pt +15 pt) (Required for PHY803 students only. +10 pts extra credit for PHY493 students.) Hadronic resonances are often labeled with the resonance mass, as the constituent quarks can be in a spin 0state, leading to a higher mass. This is commonly denoted as X(M) for a particle X with mass M in units of Mev The Λ0(1116) has the following decays: Decay Decay Mode Number Branching Fraction 0.639 t 0.005 0.358 + 0.005 0.00084 ± 0.00014 0.00175+0.00015 0.000832+ 0.000014 0.000157+ 0.000035 a) Explain why there are no r' decays listed b) Make an argument for the relative decay rates of decays (1 vs 2), (3 vs 4), and (5 vs 6). For the fully hadronic decay modes, note that the Ao has isospin zero (-0, l,-0), while l'l(p)-(%,1%); I,Mn)-(%-%); 1,1z(n-)-(1,1); and Il2(T) (1,0). The weak interactions do not conserve isospin, but there is a general trend called the Δ- rule, which implies that the net isospin of the final state hadronic system is 1,1z-(%-%)

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