1t]. 11. 12. 13. 14. 15. Why was the quark theory rst proposed? Outline the experimental evidence that supports this theory. Explain why the standard model now includes six quarks instead of the three originally suggested by (SellMano and Zweig. Identify a major difference that distinguishes (a) leptons from hadrons leptons are fundamental, hadrons are made of quarks (b) mesons from haryons baryons are heavier, different spins (c) fermions and bosons fermions have mass What experimental evidence suggests that the proton contains three smaller particles? Why do physicists require extremely high energy particles for studying the structure of nucleons? Why is it probably impossible to observe an individual quark on its own? Compare the quark composition of a proton to that of a neutron. Describe the difference between mesons and baryons in terms of quarks. Using quark theory, write an equation for the beta decay of a neutron. Show that charge is conserved in this decay process. What is missing in the following equation? Justify your answer. Identify each of the partirJes. +"rid ) said + of? uud (proton) Describe a similarity and a difference between a muon and a pion. What are two advantages of using units of liwfellt'ftE to express the mass of subatomic particles? Describe an experiment that provided evidence for the existence of quarks. Why didphysicists suspectthat there might be a sixth quark? What is the name ofthis sixth quark? Why was a huge accelerator necessary for the discovery of this quark? Determine the charge on a particle having the quark composition uus