41 research outputs found
CP-violation for Electroweak Baryogenesis from Dynamical CKM Matrix
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
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
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
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
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?
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
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
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
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