67115 - Nuclear and Subnuclear Physics

Learning outcomes

At the end, the students will acquire familiarity: with the physics of nuclei (nuclear models,nuclear stability, nuclear fission and fusion), with particular emphasis on reactions that occur in astrophysics; with the ultimate constituents of matter (quarks and leptons) and their interactions with each other (electromagnetic, strong and weak interactions). The student assimilates specific examples of connection between the microcosm and macrocosm.

Course contents

Why nuclear and subnuclear physics in a course of Astronomy (2h). Relations between astrophysics, cosmology and submicroscopic world. From atoms to quarks: from atomic physics to the sub-nuclear. Distance scales and energy. (Cap. 1 textbook)

Fundamental aspects of nuclear physics (4h). The Rutherford experiment for the determination of the atomic structure and nuclear dimensions. General properties of nuclei. Stable nuclei. Nuclide chart. The mass spectrometer for determination of the nuclear mass. Nuclear binding energy. Nuclear dimensions by scattering measurements. The charge distribution in nuclei. Nuclear models: the drop model. Binding energy per nucleon vs. mass number A: experimental determination. The semi-empirical formula for the nuclear binding energy. Early indications on the nucleons structure in terms of quarks and gluons. Nuclear reactions: examples of nuclear reactions. Spontaneous fission. Induced nuclear fission. Nuclear fusion. (Ch. 1 and 14 textbook)

Radioactive decay and dating (4h). What is a nuclear decay. The decay law: phenomenological description. Lifetime and half-life. Activities of a nucleus and measurement of radioactivity. Dating techniques. Radiocarbon dating. Radioactive decay: alpha decay. General information on beta decay. Decay of nuclei mass with event A. Decay of nuclei of odd A. Valley of stability. Gamma-rays. (Ch. 1 and 14 textbook)

From the macrocosm to the microcosm (4h). Recall of Quantum Mechanics concepts. Observable quantities. Quantum-mechanical description of the free particle. Wave function in a static potential. The Schrodinger equation. Antiparticles as negative energy states of the Dirac equation. Prediction and discovery of the anti-electron. Experimental details on the positron discovery. Charged tracks in magnetic field. Excitation / ionization energy losses. Braking radiation. General information on particle detectors. The Klein-Gordon equation and its resolution. The bosonic propagator. Potential short-range solution of the Klein-Gordon. (Ch. 2, 3 and 4 textbook)

Leptons, quarks and hadrons (6h). The discovery of new elementary particles. Detection techniques and detectors for elementary particles. Yukawa's theory of nuclear interactions. The discovery of the pion and the muon in cosmic rays. The concept of cross section. Leptons and quarks. Families of leptons and quarks. Feynman diagrams. Introduction to the four fundamental interactions. The coupling constant of gravitational interactions. The coupling constant for electromagnetic interactions (fine structure constant). General characteristics of electromagnetic interactions. Probability transition in MQ. Calculation of transition probability W with perturbation theory. Connection between W with quantities experimentally measurable (lifetimes of particles, cross sections). (Cap. 4 and 5 textbook)

Invariance principles and conservation in particle physics (2h). Parity, charge conjugation, time reversal. CP violation. General information about the decay of elementary particles: conservation of electric charge, lepton number and baryon. Effect on matter-antimatter asymmetry in the Universe (Cap. 6 textbook)

Weak interactions (6h). Pauli's hypothesis of neutrino energy conservation in beta decay. The coupling constant for the weak interactions. General characteristics of weak interactions: lifetimes, cross sections, violation of some quantities otherwise preserved. Calculating with the perturbation theory of the Fermi constant G. Measure of G from the neutron lifetime. Universality of weak interactions. Sargent's rule for the average life of nuclear beta decays. (Cap. 8 textbook)

Neutrinos (6h). Detailed description of the Reines and Cowan experiment for the discovery of the electron neutrino. Comparison between the measured and the expected values of the neutrino cross section. The helicity of the neutrino: left-handed neutrinos and right-handed antineutrinos. Muon neutrinos: description of the procedure for construction of a beam of muon neutrinos in particle accelerators. Identification of electrons and muons. Difference between nu_e and nu_mu. Conservation of lepton number for different types of leptons. Astrophysical consequences related to the properties of the neutrino (nuclear reactions in stars, stellar gravitational collapse) (Cap. 8 textbook)

Quarks static model of hadrons (6h). Introduction to particles composed of quarks: hadrons. Baryons and mesons. Cross sections and lifetimes characteristics of strong interactions. Early indications on proton / neutron symmetry for the strong interactions. Quarks "u" and "d". The pions. Electromagnetic decay of pi0. The discovery of new particles subject to strong interactions. Resonances. The baryon decuplet with J = 3/2. The discovery of the last particle. The octet baryon with J = 1/2. The pseudoscalar and vector mesons. The symmetry of the wave function for the various multiplets. Early indications of the color quantum number. The quark "s" and the strangeness quantum number. The associated production of strange quarks and antiquarks. The masses of quarks. Some stable hadrons. (Ch. 7 textbook)

Discoveries with e + e-:machines: new quarks and color quantum number (6h). General information on e + e- colliders: from AdA to LEP. The discovery in colliders of heavier quarks. The electromagnetic cross section e + e- -> mu + mu-. The e + e -> hadrons cross section. The ratio R. Experimental evidence on the quantum number of color by the ratio R. Fixed target accelerators and collider. Difference in the production of particles and energy in the center of mass. Phenomenological description of quark confinement in hadrons. Energy levels of the charmonium and estimation of the strong interactions coupling constant. Extension of the Fermi model of weak interactions to high energy: the prediction of intermediate vector bosons W +, W- and Z0. The discovery of the vector bosons at the LEP collider at CERN and. (Cap. 9 textbook)

Particles, astrophysics and cosmology (2h). Prospects for multi-messenger astrophysics

Readings/Bibliography

S. Braibant,G.Giacomelli, M. Spurio: Particles and Fundamental Interactions

http://www.springer.com/physics/particle+and+nuclear+physics/book/978-88-470-2753-4
Springer- ISBN 978-94-007-2463-1

Exercises available from: http://www.springer.com/physics/particle+and+nuclear+physics/book/978-94-007-4134-8

Additional material:

-I.S. Hugues, Elementary particles (3rd ed.)- Cambridge

-D. Griffiths, Introduction to elementary particles (2nd ed.) - Wiley-VCH

-E.M. Henley, A. Garcia, Subatomic Physics, World Scientific

Teaching methods

Lectures on blackboard and slides.

Assessment methods

Oral assesment

Teaching tools

Dedicated textbook

Office hours

See the website of Marco Cuffiani

See the website of Maurizio Spurio