| Cenco Physics

| Cenco Physics

Particle Physics

Topic #	Old Topic	Old # Hrs	New Topic #	New Topic	New # Hrs
			J	Particle physics	22
			J1	Particles and interactions	5
			J2	Particle accelerators and detectors	6
			J.2.1	Explain the need for high energies in order to produce particles of large mass.
			J.2.2	Explain the need for high energies in order to resolve particles of small size. Students should know that, to resolve a particle of size d, the de Broglie wavelength λ = h/p of the particle used to scatter from it must be of the same order of magnitude as d. The connection with diffraction may prove useful here.
			J.2.3	Outline the structure and operation of a linear accelerator and of a cyclotron.
			J.2.4	Outline the structure and explain the operation of a synchrotron. Students should be able to explain how the charged beams are accelerated, why the magnetic fields must vary and why the ring has a large radius.
			J.2.5	State what is meant by bremsstrahlung (braking) radiation.
			J.2.6	Compare the advantages and disadvantages of linear accelerators, cyclotrons and synchrotrons.
			J.2.7	Solve problems related to the production of particles in accelerators. These include the total energy of the particle in terms of its mass and kinetic energy, and the total energy available from the collision of a particle with a stationary target.
			J.2.8	Outline the structure and operation of the bubble chamber, the photomultiplier and the wire chamber.
			J.2.9	Outline international aspects of research into high-energy particle physics. Students should be aware that governments need to collaborate to construct and operate large-scale research facilities. There are very few accelerator facilities, for example, CERN, DESY, SLAC, Fermilab and Brookhaven. Results are disseminated and shared by scientists in many countries.
			J.2.10	Discuss the economic and ethical implications of high-energy particle physics research. Students should be aware that, even at the height of the Cold War, Western and Soviet scientists collaborated in the field of particle physics.
			J3	Quarks	2
			J4	Leptons and the standard model	2
			J.4.1	State the three-family structure of quarks and leptons in the standard model. Students should know that the standard model is the presently accepted theory describing the electromagnetic and weak interactions of quarks and leptons.
			J.4.2	State the lepton number of the leptons in each family.
			J.4.3	Solve problems involving conservation laws in particle reactions. Students should know that electric charge, total energy, momentum, baryon number and family lepton number are conserved in all particle reactions. Strangeness is conserved in strong and electromagnetic interactions, but not always in weak interactions.
			J.4.4	Evaluate the significance of the Higgs particle (boson). Students should know that particles acquire mass as a result of interactions involving the Higgs boson.
			J5	Experimental evidence for the quark and standard models	5
			J.5.1	State what is meant by deep inelastic scattering.
			J.5.2	Analyse the results of deep inelastic scattering experiments. Students should appreciate that these experiments provide evidence for the existence of quarks, gluons and colour.
			J.5.3	Describe what is meant by asymptotic freedom. It is sufficient for students to know that the strength of the strong interaction decreases as the energy available for the interaction increases.
			J.5.4	Describe what is meant by neutral current. A simple description in terms of processes involving Z ^o exchange is sufficient.
			J.5.5	Describe how the existence of a neutral current is evidence for the standard model. Students should know that only the standard model predicts weak interaction processes involving the exchange of a massive, neutral particle (the Z^o boson).
			J6	Cosmology and strings	2
			J.6.1	State the order of magnitude of the temperature change of the universe since the Big Bang. The temperature of the universe was 10³² K at 10^-43 s after the Big Bang and is 2.7 K at present.
			J.6.2	Solve problems involving particle interactions in the early universe. For example, problems will include calculation of the temperature: at which production of electron?positron pairs becomes possible, at which nucleosynthesis can take place, when the universe becomes transparent to radiation.
			J.6.3	State that the early universe contained almost equal numbers of particles and antiparticles.
			J.6.4	Suggest a mechanism by which the predominance of matter over antimatter has occurred. A simple explanation in terms of the impossibility of photons materializing into particle?antiparticle pairs once the temperature fell below a certain value is all that is required.
			J.6.5	Describe qualitatively the theory of strings. Students should be aware that the failure to reconcile gravitation with quantum theory has created the idea of a string as the fundamental building block of matter. The known fundamental particles are modes of vibration of the string similar to the harmonics of an ordinary vibrating string.