228 research outputs found
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.
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