Phenomenology of the Standard Model
Academic year 2024/2025
Lecturers: R. Contino and M. Nardecchia
Academic year 2024/2025
Lecturers: R. Contino and M. Nardecchia
Emails:
Time schedule:
Tuesday, 10-12, aula 8, Fermi building (from 26/11/2024)
Wednesday, 14-16, aula 4, Fermi building
Thursday, 10-12, aula Careri, Marconi building
Office hours R. Contino: on Thursdays at 16:00 (office n. 235 on second floor in Marconi building)
Office hours M. Nardecchia: on Thursdays at 14:00 (office n. 250 on second floor in Marconi building)
Google Classroom code: ewowi3i
The exam is divided into two parts
Written part: answer to one (randomly chosen) question from this list in 45 minutes
Oral part: standard exams of about 30 minutes
Before the lectures begin, it is strongly recommended to attend this conference
25/9/2024 [2h]: Overview of the lectures. Dimensional analysis, estimate of muon decay.
26/9/2024 [2h]: Phase space of two and n-bodies. Rules on how to construct models/lagrangian. Gell-Mann totalitarian principle. Counting of the physical parameters in a given model. Application of these aspects to QED.
2/10/2024 [2h]: Rewriting of the Lorentz algebra using the operators A nad B . Two dimensional irreps (1/2,0) nad (0,1/2). Kinetic and mass term in two component notation. Majorana and Dirac mass terms. Embeddig of two component spinors into a single Dirac field. QED and a possible extension with this formalism. [Wi]
3/10/2024 [2h]: Standard Model gauge group and field content. Clarification on the different indices. Most general renormalizable Lagrangian. Counting of physical parameters in the Yukawa lepton sector. [Nar]
9/10/2024 [2h]: Proof of singular value decomposition theorem. Counting of the physical parameters in the quark sector. The Higgs scalar potential in the Standard Model. [Nar]
16/10/2024 [2h]: Higgs phase, gauge boson masses, tree level couplings of the scalar Higgs with fermions and gauge bosons. Higgs decay into two fermions.
17/10/2024 [2h]: Fermion masses and mixing. Value of fermion masses. Absence of tree level FCNC. Flavour violation in charged currents, CKM. Size of moduli of CKM elements.
23/10/2024 [2h]: Phenomenology of the Higgs boson. Higgs at the LHC.
24/10/2024 [2h]: Muon decay, semileptonic quark decays. Estimate of the b-quark lifetime.
30/10/2024 [2h]: Discrete symmetries: P and C
31/10/2024 [2h]: Discrete symmetries: CP
6/11/2024 [2h]: (Contino) Introduction to Effective Field Theory: heavy particles and locality.
7/11/2024 [2h]: Parametrization of CKM matrix. Wolfenstein prametrization. Qualitative discussion on how to measure the moduli of CKM elements. Unitarity triangle and Jarlskog invariant. UTfit. Flavour violation from the Higgs sector by dim 6 operators.
13/11/2024 [2h]: (Contino) Matching EFTs: Fermi theory (tree-level example); matching observables and Green's functions, matching generating functionals; basis of EFT operators, Gell-Mann totalitarian principle.
14/11/2024 [2h]: Flavour violation in the 2HDM. BSM example of flavour violation with the Z boson. Suppression of FCNC at loop level. Discussion of the GIM mechanism at the quark level.
20/11/2024 [2h]: (Contino) More on locality and analyticity. Renormalizability of EFT. Redundancy in the basis of effective operators, use of the equations of motion, invariance of on-shell scattering amplitudes: toy example with a heavy spin-1 vector boson.
21/11/2024 [2h]: (Contino) Calculable effects in EFT (correlations, non-analytic contributions). Estimating the effective coefficients: hbar counting (loopwise expansion vs coupling expansion); power counting (example of the dipole operator in QED).
27/11/2024 [2h]: (Contino) Spurion analysis (examples: estimate of dipole operator in QED, renormalization of electron mass, Minimal Flavor Violation). Validity of EFT: example of the Fermi theory.
28/11/2024 [2h]: (Contino) More on the dipole operator and spurion analysis. Amplitude for gg->hh (gluon-fusion Higgs production) as an example of matching at 1-loop: strategy for the computation, background field technique.
29/11/2024 [2h]: (Contino) Amplitude for gg->hh (gluon-fusion Higgs production) as an example of matching at 1-loop: computation of the 1-loop amplitude and matching.
4/12/2024 [2h]: (Contino) Gluon fusion Higgs production: decoupling vs non-decoupling effects, contribution from a 4th generation. Standard Model as an EFT, accidental symmetries (classical). Anomalies: introduction, diagrammatic approach.
5/12/2024 [2h]: (Contino) Anomalies: approach à la Fujikawa with functional integral. Global (chiral) symmetry of QCD: the case of zero, equal and arbitrary quark masses; computation of the U(1) axial symmetry; accidental symmetry of 2-flavor QCD+QED and charged pion decay.
6/12/2024 [2h]: (Contino) Chiral symmetry of QCD: explicit breaking from QED; spontaneous breaking, pions as pseudo-NGB; coset space, manifold of vacua and of NGB. Chiral Lagrangian (Nf=2) at O(p^2).
11/12/2024 [2h]: (Contino) Chiral Lagrangian (Nf=2) at O(p^4): higher derivative operators, quark mass term, EM gauging. Chiral expansion and loss of perturbativity at the cutoff scale. Explicit breaking of chiral symmetry from EM interaction and quark masses; pi0 anomaly.
12/12/2024 [2h]: (Contino) Physical implications of the pi0 anomaly; parity and charge-conjugation invariance of the chiral Lagrangian; chiral Lagrangian for Nf=3. Fate of accidental symmetries of the SM: B+L anomaly; theta terms in the SM Lagrangian, strong-CP problem.
13/12/2024 [2h]: (Contino) Gauge anomalies and their cancellation in the SM; quantization of (hyper)charge. Renormalization of gauge theories at 1-loop: counterterms, Ward identities and their implication, calculation of the beta function in dimensional regularization, 1-loop beta-function of QED, QCD and of a generic gauge theory.
16/12/2024 [2h]: (Contino) Solution of RG equation: running of gauge coupling, Landau pole, dimensional transmutation. Potential between two test charges in QED: calculation at 1-loop, independence on the scale mu, high- and low-energy limits. Behavior of QED at low energy: Coulomb and free-electric phases. Behavior of QCD at low energy: confinement.
17/12/2024 [2h]: (Contino) Grand Unification: approximate unification of gauge couplings at high energies; SU(5) GUT, embedding of SM matter fields into SU(5) multiplets; scalar potential and spontaneous breaking, hierarchy problem; proton decay.
19/12/2024 [2h]: Breaking of the accidental simmetries: SMEFT and dim 5 Weinberg operator. Majorana mass, PMNS matrix. Physical parameters in the neutrino sector. SM + right handed sterile neutrino. Dirac case, see-saw mechanism. Baryon number violationg operators at dim 6.
8/1/2025 [2h]: Excat symmetries of QCD in the chiral limit. Left/Right Currents and Vector/Axial currents. Explicit breaking of the chiral symmetry by the mass terms.
9/1/2025 [2h]: Non-linear transformation of the Goldstone bosons under the chiral group. Chiral lagrangian. Leading order of the chiral lagrangina O(p^2) including gauging and mass effect. Masses of the PNGBs. [P] sez. 4.1.
15/1/2025 [2h]: Chiral currents in terms of GB scalar fields. Leptonic decay of charged pions. Mass supression due to conservation of angluar momentum. Test of lepton flavour universality.
17/1/2025 [2h, 10:00-12:00, Rasetti]: Vud extraction from data using various processes (beta nucelear decay, neutron decay and charged pion beta decay).
[Nar] M. Nardecchia, Lecture Notes
[CoAT] R. Contino, CERN Academic Training Lectures on Electroweak Symmetry Breaking
On Effective Field Theory
[GeEFT] H. Georgi, "Effective Field Theory" Ann. Rev. Nucl. Part. Sci. 43 (1993) 209
[DBK] D. B. Kaplan, Lectures on Effective Field Theory, GGI School on Fundamental Interactions, 2016 (video, notes); "Five Lectures on Effective Field Theory, 17th National Nuclear Physics Summer School, Berkely, arXiv:nucl-th/0510023
[Man] A. Manohar, Lectures at the Les Houches 2017 summer school, arXiv:1804.05863
On Naturalness and the Hierarchy Problem
't Hooft "Naturalness, chiral symmetry and spontaneous chiral symmetry breaking" in Recent Developments in Gauge Theories, Cargese Lectures, 1979
Barbieri and Giudice, NPB 306 (1988) 63
Susskind PRD 20 (1979) 2619
Giudice and Rattazzi, GGI Tea Breaks Focus Meeting on "Naturalness and the future of High Energy Physics", link to video and slides
Barbieri, Strumia, hep-ph/0007265
For a recent fit to EWPO in the SMEFT framework, see: J. de Blas et al., PoS EPS-HEP2017 (2017) 467, arXiv:1710.05402
For recent bounds on stops and gluinos, see SUSY Summary Plots in ATL-PHYS-PUB-2022-013
On the GIM Mechanism
Glashow, Iliopoulos Maiani, PRD 2 (1970) 1285
Maiani, arXiv:1303.6154
see also: [Bu], [Si]
On Electroweak Precision Tests
LEP data and final results: hep-ex/0412015; hep-ex/0509008; arXiv:1012.2367
Precision Tests of the Standard Electroweak Model, P. Langacker editor (World Scientific)
Montagna, Nicrosini, Piccinini, hep-ph/9802302
Barbieri, Cargese Lectures
Matchev, TASI Lectures hep-ph/0402031
HepFit: Ciuchini et al. arXiv:1306.4644; De Blas et al. arXiv:1608.01509, arXiv:1116.05354
GFitter: Baak et al. arXiv:1107.0975
On the determination of delta(alfa)_had: Burkhardt and Pietrzyk arXiv:1106.2991
On Anomalous TGC: Hagiwara et al. NPB 282 (1987) 253; Gounaris et al. PRD 61 (2000) 073013
On epsilon parameters: Altarelli, Barbieri PLB 253 (1990) 161; Altarelli, Barbieri, Caravaglios NPB 405 (1993) 3
On S,T,W,Y: Barbieri et al. NPB 703 (2004) 127
From arXiv:
[Do] J. Donoghue, gr-qc/9512024
[Bu] A. Buras, arXiv:hep-ph/9806471
[Co] R. Contino, arXiv:1005.4269
[GT] Y. Grossmann, P. Tanedo, arXiv:1711.03624
[Ma] S. Martin, arXiv:hep-ph/9709356
[P] A. Pich, arXiv:hep-ph/9806303
[ScSc] S. Scherer, R. Schindler, arXiv:hep-ph/0505265
[Si] L. Silvestrini, arXiv:1905.00798
[Wi] S. Willenbrock, hep-ph/0410370
[Dr] H. K. Dreiner, H. E. Haber, S. P. Martin hep-ph/0812.1594
[QS] C. Quigg, R. Shrock, PRD 79 (2009) 096002, arXiv:0901.3958
[TC] L. Susskind, PRD 20 (1979) 2619, S. Weinberg, PRD 13 (1976) 974
[Das] Das et al., PRL 18 (1967) 759
Books:
[BLS] G. Branco, L. Lavoura, J. Silva, CP Violation
[CL] T.P. Cheng, L.F. Li, Gauge Theory of Elementary Particle
[DGH] J. Donoghue, E. Golowich, B. Holstein, Dynamics of the Standard Model
[Ge] H. Georgi, Weak Interactions
[MS] F. Mandl, G. Shaw, Quantum Field Theory
[PS] M. Peskin, D. Shroeder, An introduction to Quantum Field Theory
[Sc] M. Schwartz, Quantum Field theory and the Standard Model
[Sr] M. Srednicki, Quantum Field Theory
[We1] S. Weinberg, Quantum Field Theory , Volume 1
[We2] S. Weinberg, Quantum Field Theory , Volume 2
[GK] C. Giunti, C. W. Kim, Fundamentals of Neutrino Physics and Astrophysics
Other lectures online:
Slides (powerpoint, pdf) on Higgs physics
Plots on EWPT
More Links: