Subatomic Physics

9.9. References 273
9.8. * Find information on the reactions
dd −→ p 3 H
dd −→ n 3 He
and discuss the parities of the 3 Hand 3 He.
9.9. ∗ Discuss the determination of the parity of a hyperon (not the lambda).
9.10. ∗ How would you determine the parity of the kaon? Compare your proposal
with actual experiments.
9.11. The operator for the emission of electric dipole gamma radiation is of the form
qx, whereqisacharge. The matrix element for a transition i → f is of the
form
�
Ffi = d 3 xψ ∗ f (x)qxψi(x).
Use this expression to find the parity selection rule for electric dipole radiation.
9.12. Discuss the arguments and facts that assign spin 0 and positive parity to the
alpha particle (ground state of 4 He).
9.13. Electrons and positrons emitted in weak interactions can be characterized by
their momenta and their spins.
(a) Show that a nonvanishing value of the expectation value 〈J · p〉 implies
parity nonconservation.
(b) Discuss an experiment that can be used to measure the helicity of electrons.
9.14. Assume a nucleus with a magnetic moment g factor of g = 1 to be in a
magnetic field of 1 MG. Compute the temperature at which at least 99% of
the nuclei are polarized.
9.15. Use the information given in Figs. 7.2 and 9.6 to answer the following question.
Are electron and antineutrino emitted predominantly in the same direction
or in opposite directions? (For simplicity assume the 60 Costatetobe1 + and
that of 60 Ni to be 0 + .)
9.16. Discuss the evidence for parity nonconservation in the decay π + → µ + νµ:
(a) What polarization of the muon is expected?
(b) How can the muon polarization be observed?