Modules  Area  Type  Hours  Teacher(s)  
CROMODINAMICA QUANTISTICA  FIS/02  LEZIONI  54 

The student who successfully completes the course will be able to demonstrate a solid knowledge of the field theory known as Quantum ChromoDynamics (QCD). He or she will acquire knowledge of the quark model, of the foundations of nonAbelian gauge theories and of the basic results in perturbative QCD. He or she will also acquire knowledge of the main nonperturbative aspects of QCD, such as lattice QCD, instantons, 1/N expansion and chiral symmetries. In particular, he or she will acquire a solid and detailed knowledge of the problem of chiral symmetries of strong interactions, of their "spontaneous breaking" (including the effects of the quantum anomaly in the socalled "U(1) problem"), and of the socalled "Chiral Effective Lagrangians".
During the oral examination, the student will be assessed on his/her demonstrated ability to discuss the main course contents using the appropriate terminology. Moreover, the student will be required to present (as a written report) and discuss the solution of the problems assigned by the teacher during the course.
The student will be able to solve exercises and problems and also to address himself/herself to the specialized literature on the subjects of the course.
During the oral examination, the student will be assessed on his/her demonstrated skills: in particular, the student will be required to present (as a written report) and discuss the solution of the problems assigned by the teacher during the course.
The student will be able to undertake more specialized studies or activities in Theoretical Physics.
During the oral examination, the student will be assessed on his/her acquired maturity in Theoretical Physics from his/her ability to discuss the main course contents using the appropriate terminology and from his/her ability to solve the problems assigned by the teacher during the course.
The student who attends this course should have a basic knowledge of relativistic quantum mechanics and of the canonical formalism of quantum field theory (second quantization, perturbative expansion, Feynman diagrams, etc.).
Delivery: face to face
Learning activities:
Attendance: Advised
Teaching methods:
A. FOUNDATIONS AND PERTURBATIVE METHODS IN QCD: The "Eightfold Way" of GellMann & Ne'eman, i.e., the SU(3) "flavour" symmetry. The quark model of GellMann & Zweig. The quantum number of "colour". Gaugeinvariance and YangMills nonAbelian gauge theories. Quantum ChromoDynamics (QCD) as a nonAbelian gauge theory with SU(3) "colour" symmetry. The quantization of gauge theories in the pathintegral formalism. The Feynman rules for QCD. The "beta function" of GellMannLow and the "asymptotic freedom" of QCD. The "running coupling constant".
B. NON PERTURBATIVE METHODS IN QCD: The Wilson formulation (in the Euclidean space) of "Lattice Gauge Theories". The problem of "confinament" and the Wilson criterion: the "string tension". The chiral symmetries of strong interactions and their spontaneous breaking. The method of "Effective Field Theories" and the socalled "Chiral Effective Lagrangians". The quark mass term and the masses of the pseudoscalar mesons. The "U(1) problem" and the solution given by 'tHooft, Witten and Veneziano. The limit of large number N of colours ("1/N expansion"). Instantons. The "theta" angle and the problem of strong P and CP violation.
Recommended reading includes the following works:
1) S. Weinberg, "The Quantum Theory of Fields, Volume I: Foundations; Volume II: Modern Applications".
2) M.E. Peskin & D.V. Schroeder, "An Introduction to Quantum Field Theory".
3) T.P. Cheng & L.F. Li, "Gauge Theory of Elementary Particle Physics".
4) T. Muta, "Foundations of Quantum Chromodynamics".
5) A. Smilga, "Lectures on Quantum Chromodynamics".
6) H. Georgi, "Weak Interactions and Modern Particle Theory".
Further bibliography for the most relevant original works appeared in the specialized literature will be indicated during the course.
Final oral exam, during which the student will be also required to present (as a written report) and discuss the solution of the problems assigned by the teacher during the course.
Assessment methods: