90378 - QUANTUM CHROMODYNAMICS

Conoscenze e abilità da conseguire

At the end of the course the student will be able to: i) describe the main aspects of the phenomenology of strong interactions; ii) master and present the concepts, mechanisms and formalism at the base of the Quantum Chromodynamics; iii) apply the theoretical formalism to cases of interest in high-energy physics and perform computations of relevant observables.

Contenuti

1. Motivations for QCD. Non-abelian gauge theories SU(N). Feynman rules and ghosts. Color algebra. QCD as a non-abelian gauge theory with symmetry group SU(3). BRST symmetry. Instantons.

2. Renormalisation of QCD, running coupling constant and the beta function, asymptotic freedom, renormalisation group.

3. Spinor-helicity formalism. Color decomposition of tree level QCD amplitudes. BCFW recursion relation. MHV amplitudes.

4. e+e- annihilation into hadrons at LO and NLO. Cancellation of infrared divergences. Infrared-collinear safety. Jets.

5. Hadrons in the initial state. Deep inelastic scattering, the parton model, structure functions, parton density functions. Infrared divergencies in the initial state. Collinear factorisation, splitting functions, DGLAP evolution equations.

6. Brief introduction to the Standard Model.

7. QCD at colliders. Modern experiments and phenomenological studies.

8. QCD at low energy. Effective Lagrangian and chiral symmetry.

 

Testi/Bibliografia

Books:

• M. E. Peskin and D. V. Schroeder, An Introduction to Quantum Field Theory, (Addison Wesley, 1995)

• R. K. Ellis, W. J. Stirling & B. R. Webber, QCD and Collider Physics, (Cambridge, 1996)

• M. Srednicki, Quantum Field Theory, (Cambridge University Press, 2007)

• M. Schwartz, Quantum Field Theory and the Standard Model, (Cambridge University Press, 2014)

Lecture notes on QCD:

• Paolo Nason : Introduction to QCD [PDF [http://inspirehep.net/record/476506/files/CERN-98-03.pdf?version=1] ] [1998]

• Michelangelo Mangano : Introduction to QCD [PDF [http://cds.cern.ch/record/454171] ] [1999]

• Michael Peskin : Simplifying Multi-Jet QCD Computation [PDF [https://arxiv.org/pdf/1101.2414.pdf] ] [2011]

 

Handwritten lecture notes for the course are available on Virtuale.

 

Metodi didattici

Blackboard lectures.

Modalità di verifica e valutazione dell'apprendimento

Exercises will be assigned during the lectures and listed on Virtuale. Students will be evaluated through an oral interview, during which they will be asked to present solutions to the assigned exercises and answer questions about the theory.

Studenti/sse con DSA o disabilità temporanee o permanenti: si raccomanda di contattare per tempo l’ufficio di Ateneo responsabile (https://site.unibo.it/studenti-con-disabilita-e-dsa/it). Sarà sua cura proporre agli/lle studenti/sse interessati/e eventuali adattamenti, che dovranno comunque essere sottoposti, con un anticipo di 15 giorni, all’approvazione del/della docente, che ne valuterà l'opportunità anche in relazione agli obiettivi formativi dell'insegnamento.

Orario di ricevimento

Consulta il sito web di Tiziano Peraro

Consulta il sito web di Gian Paolo Vacca