41 research outputs found

    CP-violation for Electroweak Baryogenesis from Dynamical CKM Matrix

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    We show that the CKM matrix can be the source of CP violation for electroweak baryogenesis if Yukawa couplings vary at the same time as the Higgs acquires its vacuum expectation value. This offers new avenues for explaining the baryon asymmetry of the universe. These ideas apply if the mechanism explaining the flavour structure of the Standard Model is connected to electroweak symmetry breaking. We compute the resulting baryon asymmetry for various low-scale flavour models and different configurations of the Yukawa coupling variation across the bubble wall, and show that it can naturally be of the right order.Comment: 43 pages, 17 figures; v2: replaced mismatched plot in Figure 8 and corrected a typo in the caption; v3: JCAP published version, clarifications added, results unchange

    The Last Gasp of Dark Matter Effective Theory

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    We discuss an interesting class of models, based on strongly coupled Dark Matter (DM), where sizable effects can be expected in LHC missing energy (MET) searches, compatibly with a large separation of scales. In this case, an effective field theory (EFT) is appropriate (and sometimes necessary) to describe the most relevant interactions at the LHC. The selection rules implied by the structure of the new strong dynamics shape the EFT in an unusual way, revealing the importance of higher-derivative interactions previously ignored. We compare indications from relic density and direct detection experiments with consistent LHC constraints, and asses the relative importance of the latter. Our analysis provides an interesting and well-motivated scenario to model MET at the LHC in terms of a handful of parameters.Comment: 27 pages + appendices, 7 figure

    Strongly Interacting Light Dark Matter

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    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.Comment: 6 pages, 2 figures. v3: minor change

    Electroweak Phase Transition and Baryogenesis in Composite Higgs Models

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    We present a comprehensive study of the electroweak phase transition in composite Higgs models, where the Higgs arises from a new, strongly-coupled sector which confines near the TeV scale. This work extends our study in Ref. [1]. We describe the confinement phase transition in terms of the dilaton, the pseudo-Nambu-Goldstone boson of broken conformal invariance of the composite Higgs sector. From the analysis of the joint Higgs-dilaton potential we conclude that in this scenario the electroweak phase transition can naturally be first-order, allowing for electroweak baryogenesis. We then extensively discuss possible options to generate a sufficient amount of CP violation - another key ingredient of baryogenesis - from quark Yukawa couplings which vary during the phase transition. For one such an option, with a varying charm quark Yukawa coupling, we perform a full numerical analysis of tunnelling in the Higgs-dilaton potential and determine regions of parameter space which allow for successful baryogenesis. This scenario singles out the light dilaton region while satisfying all experimental bounds. We discuss future tests. Our results bring new opportunities and strong motivations for electroweak baryogenesis.Comment: 61 pages, 29 figures, 2 tables; v2: Analysis updated to account for washout of the baryon asymmetry during reheating after the phase transition, JHEP versio

    To Profile or To Marginalize -- A SMEFT Case Study

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    Global SMEFT analyses have become a key interpretation framework for LHC physics, quantifying how well a large set of kinematic measurements agrees with the Standard Model. This agreement is encoded in measured Wilson coefficients and their uncertainties. A technical challenge of global analyses are correlations. We compare, for the first time, results from a profile likelihood and a Bayesian marginalization for a given data set with a comprehensive uncertainty treatment. Using the validated Bayesian framework we analyse a series of new kinematic measurements. For the updated dataset we find and explain differences between the marginalization and profile likelihood treatments.Comment: 38 pages, 27 figure

    From models to SMEFT and back?

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    We present a global analysis of the Higgs and electroweak sector, in the SMEFT framework and matched to a UV-completion. As the UV-model we use the triplet extension of the electroweak gauge sector. The matching is performed at one loop, employing functional methods. In the SFitter analysis, we pay particular attention to theory uncertainties arising from the matching. Our results highlight the complementarity between SMEFT and model-specific analyses

    O new physics, where art thou? A global search in the top sector

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    We provide a comprehensive global analysis of Run II top measurements at the LHC in terms of dimension-6 operators. A distinctive feature of the top sector as compared to the Higgs-electroweak sector is the large number of four-quark operators. We discuss in detail how they can be tested and how quadratic terms lead to a stable limit on each individual Wilson coecient. Predictions for all observables are computed at NLO in QCD. Our SFitter analysis framework features a detailed error treatment, including correlations between uncertainties

    Electroweak Baryogenesis through varying Yukawas in Composite Higgs models

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    Varying Yukawas open new possibilities for electroweak baryogenesis. In this talk I will start by introducing varying Yukawas as a source of CP-violation and explain how baryogenesis can be successful in this framework. I will then present a realization of this paradigm in Composite Higgs models with partial compositeness. Composite Higgs models are, apart from the usual benefits, particularly compelling for this scenario as they feature an intimate link between flavour and Higgs physics. We will see that baryogenesis can be successful in these models if the confinement phase transition happens at the same time as the electroweak phase transition. I will identify regions in parameter space where this is fulfilled and I will compute the baryon yield of those models

    CP-violation and baryon-asymmetry from varying Yukawas at the weak scale

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    Varying Yukawas open new possibilities for electroweak baryogenesis. In particular varying Yukawas, if somehow related to the mechanism of electro-weak symmetry breaking, can account for a strongly first order phase transition and they can provide a new source of CP-violation. In this talk I will focus on the CP-violation and the calculation of the final baryon-asymmetry. Starting from first principles, I will derive the general form of the CP-violating force and the diffusion equations for models with varying Yukawa couplings. This represents a very general framework to determine the baryon-asymmetry generated in a given model. I will discuss the necessary ingredients for successful baryogenesis and I will apply this framework to different models and discuss the CP-violation and the amount of baryon-asymmetry produced
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