Introduction to flavour physics

We give a brief introduction to flavour physics. The first part covers the flavour structure of the Standard Model, how the Kobayashi-Maskawa mechanism is tested and provides examples of searches for new physics using flavour observables, such as meson mixing and rare decays. In the second part we give a brief overview of the recent flavour anomalies and how the Higgs can act as a new flavour probe.Comment: 32 pages, 22 figures, the write-up is a combination of lectures given at ESHEP 2018, SSI 2018 and the US Belle II summer schools, Fig. 1 corrected, several typographical errors fixe

Constraints on CP-violating Higgs couplings to the third generation

Discovering CP-violating effects in the Higgs sector would constitute an indisputable sign of physics beyond the Standard Model. We derive constraints on the CP-violating Higgs-boson couplings to top and bottom quarks as well as to tau leptons from low-energy bounds on electric dipole moments, resumming large logarithms when necessary. The present and future projections of the sensitivities and comparisons with the LHC constraints are provided. Non-trivial constraints are possible in the future, even if the Higgs boson only couples to the third-generation fermions.Comment: 26 pages, 10 figures; typos corrected, version as published in JHE

Integrating in the Higgs Portal to Fermion Dark Matter

Fermion dark matter (DM) interacting with the standard model through a Higgs portal requires non-renormalizable operators, signaling the presence of new mediator states at the electroweak scale. Collider signatures that involve the mediators are a powerful tool to experimentally probe the Higgs portal interactions, providing complementary information to strong constraints set by direct DM detection searches. Indirect detection experiments are less sensitive to this scenario. We investigate the collider reach for the mediators using three minimal renormalizable models as examples, and requiring the fermion DM to be a thermal relic. The Large Hadron Collider in its high-energy, high-luminosity phase can probe most scenarios if DM is lighter than about 200 GeV. Beyond this scale, future high-energy experiments such as an electron-positron collider or a 100-TeV proton-proton collider, combined with future direct detection experiments, are indispensable to conclusively test these models.Comment: 23 pages; v2: references added and correction of direct detection limits in section VI.