Particle Physics


course ID

Lecturer

CFU

6

Length

14 Weeks

Semester DD

First


Course details

Introduction, particles and forces. Mandelstam variables, Fermi's golden rule, Lorentz invariant phase space, two-body decays, cross section. Klein-Gordon equation, Dirac equation, probability density and covariance. Solutions to the Dirac equation for an electron at rest. General solutions of the Dirac Equation, Antiparticles and its spinor, normalisation of the wavefunction. Spin and Helicity. Interaction by particle exchange, time-ordered 2->2 matrix element, Feynman diagrams, examples and algebra of matrices. Parity operator, Range of forces, Yukawa potential, QED matrix element for electron-tau scattering, Feynman rules for QED. QED as a perturbative theory, Spin sums in e+e- to mu+mu- annihilation, the e+e- to mu+mu- cross section and its Lorentz-invariant form, examples of application of the Feynman rules. Chirality Operator, Charge Conjugation. Electron-proton elastic scattering: Rutherford, Mott, Rosenbluth formulae, Form factors. Electron-proton elastic scattering at high-Q2, e-p inelastic scattering, e-p inelastic scattering at low-Q2 and high-Q2 (DIS), Bjorken scaling and Callan-Gross relation, Electron-quark scattering. Quark-Parton Model, Parton Density Functions, Valence and Sea quarks, electron-proton scattering at HERA. Symmetries and Conservation laws, SU(2) flavour symmetry, 2 and 3 quarks combinations in SU(2), Light quark (ud) baryons and mesons. SU(3) flavour symmetry, Gell-Mann matrices, Ground state light quark (uds) Mesons and Baryons, Hadron mass and constituent mass. Local gauge invariance in QED and QCD, Colour in QCD, colour confinement, Meson and Baryon colour wavefunctions, Gluons, quark-gluon and gluon-gluon interactions, Hadronisation and jets, hadroproduction in e+e- collisions. Running coupling constants in QED and QCD, Asymptotic freedom. Colour factors. Hadronic collisions and Drell-Yan. Jet production in hadronic collisions. Rapidity and pseudorapidity, Drell-Yan process, Parity in QED and QCD matrix elements, Parity Violation in weak-interactions. V-A structure of the weak interaction, Chiral properties of V-A, W boson propagator, Fermi theory, Helicity in pion decay and evidence for V-A, lepton universality of the electroweak coupling. (Anti)Neutrino-quark scattering, neutrino-nucleon cross sections, CDHS experiment. Neutrino mass and flavour eigenstates, Neutrino oscillations in 2 and 3 families, Phenomenology of neutrino experiments. CP violation in neutrino mixing, PMNS matrix, Neutrino oscillation experiments and determination of the PMNS parameters and masses. Quark mixing in weak interactions, Cabibbo angle and GIM mechanism, CKM matrix and its representations. Neutral kaons system. Kaon oscillations, CP violation in oscillations and decays. B and B_s oscillations, B factories. W boson decay width and branching ratios. Electroweak SU(2)_L gauge structure, Neutral current, Electroweak unification, the Z boson. Breit-Wigner resonance, Z production cross section in e+e- collisions, measurements of Z boson mass and width, Z FB asymmetry and weak mixing angle, the LEP collider, W boson mass and width. Decay rate of the top quark, top quark production at hadronic colliders, Higgs boson and its discovery.

Objectives

The course aims to provide the student with a solid background in particle physics. The main emphasis is on the experimental aspects of particle physics with a focus on the most recent research themes.  The course’s approach to the quark and the electroweak standard model is phenomenological, stressing the implication of the theory on the properties of particles.  A simplified treatment of Feynman’s diagrams gives the student the ability to perform simple calculations of cross-sections and decays. The production and decay mechanisms of W, Z and Higgs particles are presented, focusing on the experimental consequences.  Particle oscillations and violations of the CP symmetry are discussed at advanced level. A survey of the neutrino oscillations is also discussed.