A deep survey of the Large Magellanic Cloud at ∼ 0.1−100 TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3 − 2.4 pending a flux increase by a factor > 3 − 4 over ∼ 2015 − 2035. Large-scale interstellar emission remains mostly out of reach of the survey if its > 10 GeV spectrum has a soft photon index ∼ 2.7, but degree-scale 0.1 − 10 TeV pion-decay emission could be detected if the cosmic-ray spectrum hardens above >100 GeV. The 30 Doradus star-forming region is detectable if acceleration efficiency is on the order of 1 − 10% of the mechanical luminosity and diffusion is suppressed by two orders of magnitude within < 100 pc. Finally, the survey could probe the canonical velocity-averaged cross section for self-annihilation of weakly interacting massive particles for cuspy Navarro-Frenk-White profiles.

Short-lived mediators are often used to describe dark matter interactions with Standard Model particles. When the dark matter mass is heavier than the mass of the mediator, it may self-annihilate into short-lived mediators, and in some cases this might be the dominant annihilation channel. This scenario is known as secluded dark matter. We use Fermi-LAT observations of dwarf spheroidal galaxies, H.E.S.S. data from the Galactic center, and Planck measurements of the Cosmic Microwave Background to constrain secluded dark matter. We explore the interplay between these experiments and we assess the impact of the mediator mass on our bounds, an often overlooked yet very important point. In particular, we exclude pair -annihilation cross-sections greater or on the order of σv ∼ 4 × 10 −27 cm 3 /s for dark matter masses around 10 GeV and greater or on the order of σv ∼ ×10 −25 cm 3 /s for dark matter masses around a TeV. Our findings supersede previous constraints which use Fermi-LAT data, and constitute the first limits on secluded dark sectors using the H.E.S.S. telescope. We also show that one can fit TeV gamma-ray observations from H.E.S.S. with secluded dark matter annihilations, with the mediator mass impacting the best-fit dark matter particle mass. Our findings indicate that any assessment of secluded dark sectors in the context of indirect detection significantly depends on the choice of the mediator mass. 1 4πσv 4.4 × 10 −25 cm 3 /s Planck CMB 4b, M DM = 100 GeV CMB 4b, M DM = 1 TeV M DM M V → σv 2.5 × 10 −25 cm 3 /s M DM M V → σv 3 × 10 −24 cm 3 /s M DM ∼ M V → σv 2.5 × 10 −25 cm 3 /s M DM ∼ M V → σv 2.5 × 10 −24 cm 3 /s CMB 4e, M DM = 100 GeV CMB 4e, M DM = 1 TeV M DM M V → σv 10 −25 cm 3 /s M DM M V → σv 10 −24 cm 3 /s M DM ∼ M V → σv 1.5 × 10 −25 cm 3 /s M DM ∼ M V → σv 1.5 × 10 −24 cm 3 /s

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We discuss the phenomenology of an MeV-scale Dirac fermion coupled to the Standard Model through a dark photon with kinetic mixing with the electromagnetic field. We compute the dark matter relic density and explore the interplay of direct detection and accelerator searches for dark photons. We show that precise measurements of the temperature and polarization power spectra of the Cosmic Microwave Background Radiation lead to stringent constraints, leaving a small window for the thermal production of this MeV dark matter candidate. The forthcoming MeV gamma-ray telescope e-ASTROGAM will offer important and complementary opportunities to discover dark matter particles with masses below ∼ 10 MeV. Lastly, we discuss how a late-time inflation episode and freeze-in production could conspire to yield the correct relic density while being consistent with existing and future constraints.

Within the context of vector mediators, is a new signal observed in flavor changing interactions, particularly in the neutral mesons systems K 0 −K 0 , D 0 −D 0 and B 0 −B 0 , consistent with dilepton resonance searches at the LHC? In the attempt to address this very simple question, we discuss the complementarity between flavor changing neutral current (FCNC) and dilepton resonance searches at the LHC run 2 at 13 TeV with 3.2 fb −1 of integrated luminosity, in the context of vector mediators at tree level. Vector mediators, are often studied in the flavor changing framework, specially in the light of the recent LHCb anomaly observed at the rare B decay. However, the existence of stringent dilepton bound severely constrains flavor changing interactions, due to restrictive limits on the Z mass. We discuss this interplay explicitly in the well motivated framework of a 3-3-1 scheme, where fermions and scalars are arranged in the fundamental representation of the weak SU(3) gauge group. Due to the paucity of relevant parameters, we conclude that dilepton data leave little room for a possible new physics signal stemming from these systems, unless a very peculiar texture parametrization is used in the diagonalization of the CKM matrix. In other words, if a signal is observed in such flavor changing interactions, it unlikely comes from a 3-3-1 model.

A puzzling excess in gamma-rays at GeV energies has been observed in the center of our galaxy using Fermi-LAT data. Its origin is still unknown, but it is well fitted by Weakly Interacting Massive Particles (WIMPs) annihilations into quarks with a cross section around 10 −26 cm 3 s −1 with masses of 20 − 50 GeV, scenario which is promptly revisited. An excess favoring similar WIMP properties has also been seen in anti-protons with AMS-02 data potentially coming from the Galactic Center as well. In this work, we explore the possibility of fitting these excesses in terms of semi-annihilating dark matter, dubbed as semi-Hooperon, with the process WIMP WIMP → WIMP X being responsible for the gamma-ray excess, where X=h,Z. An interesting feature of semi-annihilations is the change in the relic density prediction compared to the standard case, and the possibility to alleviate stringent limits stemming from direct detection searches. Moreover, we discuss which models might give rise to a successful semi-Hooperon setup in the context of Z3,Z4 and extra "dark" gauge symmetries.

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We investigate simplified models involving an inert scalar triplet and vectorlike leptons that can account for the muon g − 2 anomaly. These simplified scenarios are embedded in a model that features W' and Z' bosons, which are subject to stringent collider bounds. The constraints coming from the muon g − 2 anomaly are put into perspective with collider bounds, as well as bounds coming from lepton flavor violation searches. The region of parameter space that explains the g − 2 anomaly is shown to be within reach of lepton flavor violation probes and future colliders such as HL-LHC and HE-LHC.