While the main textbook includes many worked examples, mastering particle physics requires active problem-solving. The nearly 300 problems in Griffiths' text are designed to test and build your understanding. They range from simple historical derivations to complex calculations of scattering cross-sections using Feynman rules.
If you get completely stuck, open the solutions manual only to look at the initial setup or the first two lines of the derivation. Close the manual immediately and try to finish the problem based on that hint. While the main textbook includes many worked examples,
: Detailed walkthroughs of cross-section and lifetime calculations using Feynman rules. While the main textbook includes many worked examples,