Subatomic Physics

11.15. References 379
(b) * Discuss experiments that could give information about W .
11.23. Find some examples other than the ones given in Table 11.3 to demonstrate
that strangeness-changing weak decays are systematically slower than the corresponding
strangeness-conserving ones. Use your examples to find a value
for the sine of the Cabibbo angle, Vus.
11.24. Verify that the wave functions of the neutrino and the electrons, given in
Eq. (11.62), are essentially constant over the nuclear volume.
11.25. Prove in detail that the integral containing A in Eq. (11.63) vanishes.
11.26. The computation of the lepton matrix element in Eq. (11.67) gives
|u ∗ e (V0 + A0)u¯ν| 2 �
=2 1+ v
�
cos θeν ,
c
where v is the positron velocity and θeν the angle between positron and neutrino
momenta.
(a) How can the positron–neutrino correlation be measured? Discuss the
principle of the method and a typical experiment.
(b) Show that the observed positron–neutrino (and electron–antineutrino)
correlations are in agreement with a V−Ainteraction.
11.27. * List some superallowed 0 + → 0 + transitions and show that their ft values
are all closely identical.
11.28. High-energy neutrinos have been observed in bubble chambers (propane and
hydrogen) and in spark chambers.
(a) Compare typical count rates.
(b) What are the advantages and the disadvantages of the various detectors?
11.29. Plot a few numerical values of the cross section equation (11.94) as a function
of the neutrino momentum
(a) In the c.m.
(b) In the laboratory.
Compare your curves with the ones shown in Figs. 11.16 and 11.18.