Narrow Results

The Dirac scotogenic model provides an elegant mechanism which explains small Dirac neutrino masses and neutrino mixing, with a single symmetry simultaneously protecting the “Diracness” of the neutrinos and the stability of the dark matter candidate. Here, we explore the phenomenological implications of the recent CDF-II measurement of the W boson mass in the Dirac scotogenic framework. We show that, in the scenario where the dark matter is mainly a $\mathrm{\text{SU}}{(2)}_L$ scalar doublet, it can satisfy all the theoretical and experimental constraints along with the CDF-II W boson mass for the mass range of 58–86 GeV. However, unlike the Majorana scotogenic model, the Dirac version also has a “dark sector” SU(2)_L singlet scalar. We show that if the singlet scalar is the lightest dark sector particle, i.e. the dark matter then all neutrino physics and dark matter constraints along with the constraints from oblique S, T and U parameters can be concurrently satisfied for W boson mass in the CDF-II mass range, where the singlet dark matter mass is constrained up to around 500 GeV.

In a wino LSP scenario the annihilation cross-section of winos gravitationally bound in galaxies can be boosted by a Sommerfeld enhancement factor which arises due to the ladder of exchanged W bosons between the initial states. The boost factor obtained can be in the range S ≃10⁴ if the mass is close to the resonance value of M ≃4 TeV. In this paper we show that if one takes into account the Sommerfeld enhancement in the relic abundance calculation then the correct relic density is obtained for 4 TeV wino mass due to the enhanced annihilation after their kinetic decoupling. At the same time the Sommerfeld enhancement in the χχ→W⁺ W^- annihilation channel is sufficient to explain the positron flux seen in PAMELA data without significantly exceeding the observed antiproton signal. We also show that (e^-+e⁺) and γ-ray signals are broadly compatible with the Fermi-LAT observations. In conclusion we show that a 4 TeV wino DM can explain the positron and antiproton fluxes observed by PAMELA and at the same time give a thermal relic abundance of CDM consistent with WMAP observations.

The relic abundance of asymmetric dark matter particles in the scalar-tensor model is analyzed in this paper. We extend the numerical and analytical calculations of the relic density of the asymmetric dark matter in the standard cosmological scenario to the nonstandard cosmological scenario. We focus on the scalar-tensor model. Hubble expansion rate is changed in the nonstandard cosmological scenario. This leaves its imprint on the relic density of dark matter particles. In this paper we investigate to what extent the asymmetric dark matter particle’s relic density is changed in the scalar-tensor model. We use the observed present day dark matter abundance to find the constraints on the parameter space in this model.

The ATLAS report in August 2016 provided an upper limit for the pp$\to$diboson and $t\bar{t}$ cross-sections. We consider a pseudoscalar-mediated fermionic dark matter together with gluon and photon effective operators interacting with the pseudoscalar. Choosing the resonance mass being $m_{\rho }=200$, 750 GeV and 2 TeV, beside the relic density and the invisible Higgs decay constraints we constrain more the space of parameters with the diboson and $t\bar{t}$ cross-section upper bounds. We finally provide some benchmarks consistent with all the constraints. Having exploited a pseudoscalar mediator, the DM-nucleon cross-section is velocity suppressed so that the model evades easily the bounds put by the future direct detection experiments such as XENON1T.

We analyze dark matter in most general form of effective field theory approach. To examine the interactions between the weakly interacting massive particles (WIMPs) and the Standard Model (SM) particles, we use the six-dimensional EFT mediated by new physics scale $\mathrm{\Lambda }$ at tree level. After implementing a new effective field theory model in FeynRules [FeynRules 2.0 A complete toolbox for tree-level phenomenology, Comput. Phys. Comm.185(8) (2014) 2250–2300] We investigate the theory and constrain the theory by using relic density generated by MadDM [MadDM v.3.0: A Comprehensive tool for dark matter studies, Phys. Dark Univ.24 (2019) 100249] tool of MadGraph5_aMC@NLO [The automated computation of tree-level and next-to-leading order differential cross-sections, and their matching to parton shower simulations, J. High Energy Phys.79 (2014) 2014].

We present an analysis of fermionic dark matter (DM) in the context of 6-dimensional Effective Field Theory (EFT). We also compared the result generated via 6-dimensional EFT analysis with the current experimental results for dark matter searches. These experiments are methodically categorized as direct and indirect searches and present some constraints on dark matter model parameters of 6-dimensional EFT. We constructed a new set of tools ensuring DM researches in various platforms. The model parameters are presented to guide DM production in colliders by taking account of the upper limits at direct and indirect searches. In this paper, we apply our approach for fermionic case to test the verification of the method. There are various types of search methods for DM, each depends on type of interaction of dark matter with SM particles. Finally we analyzed fermionic DM candidate of 6-dimensional Effective Field Theory (EFT) at the platforms of DM searches. A new set of numerical tools is specified for 6-dimensional fermionic DM model, and these tools are also tested.

We give a prescription how high energy physics tools can be used to perform scalar dark matter analysis. We also present the analysis results of scalar dark matter in the context of 6 dimensional Effective Field Theory. We present the relic density and the cross sections of s scalar DM with the current results of the actual experiments.

These lecture notes describe the micrOMEGAs package for the calculation of Dark Matter observables in extensions of the standard model.