Griffiths Introduction to Elementary Particles · Problem 2.5

Relativistic Kinematics — David J. Griffiths

Physics — QFT · decays-conservation-laws

Problem

(a) Which decay do you think would be more likely,

\Xi^- \rightarrow \Lambda + \pi^- \quad \text{or} \quad \Xi^- \rightarrow n + \pi^-

Explain your answer, and confirm it by looking up the experimental data. (b) Which decay of the

D^0(c\bar{u})

meson is more likely,

D^0 \rightarrow K^- + \pi^+, \quad D^0 \rightarrow \pi^- + \pi^+, \quad \text{or} \quad D^0 \rightarrow K^+ + \pi^-

Which is least likely? Draw the Feynman diagrams, explain your answer and check the experimental data. (One of the successful predictions of the Cabibbo/GIM/KM model was that charmed mesons should decay preferentially into strange mesons, even though energetically the

2\pi

mode is favored.) (c) How about the ``beautiful'' (

B

) mesons? Should they go to the

D

's,

K

's, or

\pi

's? How about ``truthful'' mesons?

Related theory

Conservation Laws

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