Muon g-2 and B Anomalies from Dark Matter.

In light of the recent result of the muon g-2 experiment and the update on the test of lepton flavor universality R_{K} published by the LHCb Collaboration, we systematically study for the first time a set of models with minimal field content that can simultaneously give (i) a thermal dark matter candidate; (ii) large loop contributions to b→sℓℓ processes able to address R_{K} and the other B anomalies; (iii) a natural solution to the muon g-2 discrepancy through chirally enhanced contributions. Moreover, this type of model with heavy particles and chiral enhancement can evade the strong limits from direct searches but can be tested at present and future colliders and direct-detection searches.

The waning of the WIMP? A review of models, searches, and constraints.

Weakly Interacting Massive Particles (WIMPs) are among the best-motivated dark matter candidates. No conclusive signal, despite an extensive search program that combines, often in a complementary way, direct, indirect, and collider probes, has been detected so far. This situation might change in near future due to the advent of one/multi-TON Direct Detection experiments. We thus, find it timely to provide a review of the WIMP paradigm with focus on a few models which can be probed at best by these facilities. Collider and Indirect Detection, nevertheless, will not be neglected when they represent a complementary probe.

Dark matter phenomenology of SM and enlarged Higgs sectors extended with vector-like leptons.

We will investigate the scenario in which the Standard Model (SM) Higgs sector and its two-doublet extension (called the Two Higgs Doublet Model or 2HDM) are the "portal" for the interactions between the Standard Model and a fermionic Dark Matter (DM) candidate. The latter is the lightest stable neutral particle of a family of vector-like leptons (VLLs). We will provide an extensive overview of this scenario combining the constraints coming purely from DM phenomenology with more general constraints like Electroweak Precision Test (EWPT) as well as with collider searches. In the case that the new fermionic sector interacts with the SM Higgs sector, constraints from DM phenomenology force the new states to lie above the TeV scale. This requirement is relaxed in the case of 2HDM. Nevertheless, strong constraints coming from EWPTs and the Renormalization Group Equations (RGEs) limit the impact of VLFs on collider phenomenology.

Searching for dark matter at colliders.

Dark Matter (DM) detection prospects at future [Formula: see text] colliders are reviewed under the assumption that DM particles are fermions of the Majorana or Dirac type. Although the discussion is quite general, one will keep in mind the recently proposed candidate based on an excess of energetic photons observed in the center of our Galaxy with the Fermi-LAT satellite. In the first part we will assume that DM interactions are mediated by vector bosons, [Formula: see text] or [Formula: see text]. In the case of [Formula: see text]-boson Direct Detection limits force only axial couplings with the DM. This solution can be naturally accommodated by Majorana DM but is disfavored by the GC excess. Viable scenarios can be instead found in the case of [Formula: see text] mediator. These scenarios can be tested at [Formula: see text] colliders through ISR events, [Formula: see text]. A sensitive background reduction can be achieved by using highly polarized beams. In the second part scalar particles, in particular Higgs particles, have been considered as mediators. The case of the SM Higgs mediator is excluded by limits on the invisible branching ratio of the Higgs. On the contrary particularly interesting is the case in which the DM interactions are mediated by the pseudoscalar state [Formula: see text] in two Higgs-doublet model scenarios. In this last case the main collider signature is [Formula: see text].