20 research outputs found
Yukawa sector of multi-Higgs-doublet models in the presence of Abelian symmetries
A general method for classifying the possible quark models of a multi-Higgs-doublet model, in the presence of Abelian symmetries, is presented. All the possible sets of textures that can be present in a given sector are shown, thus turning the determination of the flavor models into a combinatorial problem. Several symmetry implementations are studied for two and three Higgs doublet models. Some models' implementations are explored in great detail, with a particular emphasis on models known as Branco-Grimus-Lavoura and nearest-neighbor-interaction. Several considerations on the flavor changing neutral currents of multi-Higgs models are also given
Effective Aligned 2HDM with a DFSZ-like invisible axion
We discuss the possibility of having a non-minimal scalar sector at the weak
scale within the framework of invisible axion models. To frame our discussion
we consider an extension of the Dine-Fischler-Srednicki-Zhitnitsky invisible
axion model with two additional Higgs doublets blind under the Peccei-Quinn
symmetry. Due to mixing effects among the scalar fields, it is possible to
obtain a rich scalar sector at the weak scale in certain decoupling limits of
the theory. In particular, this framework provides an ultraviolet completion of
the so-called aligned two-Higgs-doublet model and solves the strong CP problem.
The axion properties and the smallness of active neutrino masses are also
discussed.Comment: 8 pages, 1 figure. Discussion improved, references added. Matching
the journal versio
An invisible axion model with controlled FCNCs at tree level
We derive the necessary conditions to build a class of invisible axion models
with Flavor Changing Neutral Currents at tree-level controlled by the fermion
mixing matrices and present an explicit model implementation. A horizontal
Peccei-Quinn symmetry provides a solution to the strong CP problem via the
Peccei-Quinn mechanism and predicts a cold dark mater candidate, the invisible
axion or familon. The smallness of active neutrino masses can be explained via
a type I seesaw mechanism, providing a dynamical origin for the heavy seesaw
scale. The possibility to avoid the domain wall problem stands as one of the
most interesting features of the type of models considered. Experimental limits
relying on the axion-photon coupling, astrophysical considerations and familon
searches in rare kaon and muon decays are discussed.Comment: 7 pages, 1 table, 1 figure. Discussion extended, references added.
Matching the journal versio
Models with three Higgs doublets in the triplet representations of A(4) or S-4
We consider the quark sector of theories containing three scalar SU(2)(L) doublets in the triplet representation of A(4) (or S-4) and three generations of quarks in arbitrary A(4) (or S-4) representations. We show that for all possible choices of quark field representations and for all possible alignments of the Higgs vacuum expectation values that can constitute global minima of the scalar potential, it is not possible to obtain simultaneously nonvanishing quark masses and a nonvanishing CP-violating phase in the Cabibbo-Kobayashi-Maskawa quark mixing matrix. As a result, in this minimal form, models with three scalar fields in the triplet representation of A(4) or S-4 cannot be extended to the quark sector in a way consistent with experiment
Constraining multi-Higgs flavour models
To study a flavour model with a non-minimal Higgs sector one must first
define the symmetries of the fields; then identify what types of vacua exist
and how they may break the symmetries; and finally determine whether the
remnant symmetries are compatible with the experimental data. Here we address
all these issues in the context of flavour models with any number of Higgs
doublets. We stress the importance of analysing the Higgs vacuum expectation
values that are pseudo-invariant under the generators of all subgroups. It is
shown that the only way of obtaining a physical CKM mixing matrix and,
simultaneously, non-degenerate and non-zero quark masses is requiring the
vacuum expectation values of the Higgs fields to break completely the full
flavour group, except possibly for some symmetry belonging to baryon number.
The application of this technique to some illustrative examples, such as the
flavour groups Delta(27), A4 and S3, is also presented.Comment: 13 pages, 3 figures, title and abstract changed, comments and
references added; matches version to appear in The European Physical Journal
Real-time Accelerator Diagnostic Tools for the MAX IV Storage Rings
In this paper, beam diagnostic and monitoring tools developed by the MAX IV
Operations Group are discussed. In particular, new beam position monitoring and
accelerator tunes visualization software tools, as well as tools that directly
influence the beam quality and stability are introduced. An availability and
downtime monitoring application is also presented
Report from Working Group 3: Beyond the standard model physics at the HL-LHC and HE-LHC
This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as ab of data taken at a centre-of-mass energy of 14 TeV, and of a possible future upgrade, the High Energy (HE) LHC, defined as ab of data at a centre-of-mass energy of 27 TeV. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will, generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics