Exploring and decoding theories of New Physics at colliders and beyond

Abstract

A qualitatively new approach is taken in building Minimal Consistent Dark Matter (MCDM) models, which facilitate the interpretation of complementary experimental results for Dark Matter (DM). These models offer broader applicability than EFTs and greater consistency with the symmetries of the SM than Simplified Models. Although many of these models have been studied in the literature, we offer a complete systematic classification of possible MCDM models before discussing the phenomenology of such models. We perform extensive numerical studies of the phenomenology of a simple but novel representative MCDM model at NLO, which gives rise to two-component DM. We present a model independent method to measure the mass of a DM particle (D) if it appears alongside a charged partner (D±) at e+e− colliders. This takes advantage of kinematic features of the energy distribution of charged leptons emitted from a W± lepton emitted in cascade decays D± → W±D. We apply this to consistent models of both Dirac fermion and scalar thermal DM, at benchmark points which produce the observed DM density and evade direct detection experimental bounds. Realistic simulations are performed to detector level, and an optimised analysis cut-flow is proposed. Mass resolution for D,D± in this analysis was found to be better than 20% for the benchmarks considered. Furthermore, we explore a method to distinguish the spin of the DM particle using the angular distribution of W± reconstructed from di-jets. Precision electroweak data, a light higgs and LHC searches for new spin one particles are all very constraining on technicolor models. We use a holographic model of walking techicolor (WTC) gauge dynamics, tuned to produce a light higgs and low S parameter, to estimate the range of possible vector(ρ) and pseudo-vector(A) resonance masses and couplings as a function of the number of colours and the number of flavours of technisinglet and techni-doublet quarks. The resulting models predict techni-hadron masses and couplings above the current limits from dilepton resonance searches at the LHC because their masses are enhanced by the strong coupling extending into the multiTeV range, while couplings to Standard Model fermions are partly suppressed. The models emphasize the contortions needed to continue to realize technicolor, the need to explore new signatures beyond dilepton for LHC and also motivate a 100 TeV proton collider.

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Identifiers

ORCID for Alexander Belyaev: orcid.org/0000-0002-1733-4408

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