Josh Bendavid (California Institute of Technology)
Dr. Ljiljana Morvaj (Stony Brook University)
Non-minimal Higgs: experimental overview of searches with ATLAS and CMS detectors at the LHC.
Abdelhak Djouadi (LPT Orsay)
Prof. Bernd Kniehl (II. Inst. f. Theor. Phys., Univ. Hamburg)
We perform a manifestly gauge-independent analysis of the vacuum stability in the Standard Model (SM) including two-loop matching, three-loop renormalization group evolution, and pure QCD corrections through four loops. Exploiting our knowledge of the Higgs-boson mass, we derive an upper bound on the pole mass of the top quark by requiring that the SM be stable all the way up to the...
Prof. Sven-Olaf Moch (Universität Hamburg)
The current state of precision predictions for the production of the Standard Model Higgs boson in gluon-gluon fusion will reviewed. The impact of higher-order radiative corrections in QCD will be discussed. Special emphasis will be put on uncertainties from parameters of the Standard Model such as the value of the strong coupling constant and parton distribution functions.
Prof. Per Osland (University of Bergen)
I shall discuss various criteria for having CP violation in the 2HDM, expressed in terms of physical quantities like masses and couplings.
Maria Krawczyk (Warsaw)
I will discuss the Inert Doublet Model, which contains SM-like Higgs Doublet and Dark Doublet, and its extension with a complex singlet.
Prof. Gustavo Branco (CFTP/ Dep. Fisica Tecnico- Universidade Lisboa)
We examine the question of how to suppress FCNC in 2-Higgs Doublet Models and illustrate the use of weak-basis invariants for studying the flavour structure and CP violation in Multi-Higgs Models.
Martti Raidal (NICPB, Tallinn)
I discuss how the observed hierarchy in the Standard Model Yukawa couplings may radiatively originate from the dark sector dynamics. The associated dark photons and the mediator sector that transfers the dark hierarchy to the Standard Model offer distinguishing experimental tests at high and low energy experiments.
Dr. Miha Nemevšek (Institute Jožef Stefan)
The discovery of the Higgs boson and its relation to the mass of elementary particles in the SM still leaves open the question of the origin of neutrino mass. After Majorana’s discovery that neutrinos could be their own antiparticles searches for phenomenological consequences of lepton number violation are well underway. They range from neutrino-less double beta decay to collider searches. We...
Margarida (Gui) Nesbitt Rebelo (CFTP/IST/UL)
We work with a CP conserving S3-symmetric three-Higgs-doublet potential and analyse the possible real and complex vacua with emphasis on the cases in which the CP symmetry can be spontaneously broken. Some of these implementations can in principle accommodate dark matter and for that purpose it is important to identify the residual symmetries of the potential after spontaneous symmetry...
Prof. Graham Ross (Rudolf Peierls Centre for Theoretical Physics)
The discovery of the Brout-Englert-Higgs boson with a mass of 125 GeV is in excellent agreement with the SUSY expectation of an elementary scalar with mass less than 140GeV. However the non-observation of SUSY partners of Standard Model states raises doubts that SUSY solves the hierarchy problem, the main argument for expecting SUSY at low scales. The talk presents a re-evaluation of the...
Prof. Arthur Hebecker (Heidelberg University)
I will argue that the energy scale at which the Higgs quartic coupling runs to zero may be identified with the scale at which supersymmetry is broken. The vanishing of the quartic coupling at that scale could be related to a string-motivated shift symmetry. Alternatively, and in contrast to naive expectations, the scale at which SUSY breaks may also be much higher. The UV value of the quartic...
Jose R. Espinosa (ICREA/IFAE)
*The SM electroweak vacuum lies very close to the boundary between stability and metastability, with the last option the most likely. I will discuss several cosmological implications of this near-criticality. In the metastable vacuum case, I will describe the main challenges that the survivall of the EW vacuum faces. In the stable case, I will critically examine the possibility of...
Dr. Marieke Postma (Nikhef)
In the paradigm of Higgs inflation the standard model Higgs field plays the role of the inflaton, and provides an almost-constant vacuum energy to exponentially expand the universe during its initial stages. For this to work, a non-minimal coupling to gravity is introduced. At the classical level, the model is simple, predictive and agrees extremely well with the cosmic microwave background...
Prof. Arttu Rajantie (Imperial College London)
The Standard Model of particle physics predicts, for the current experimental values of the parameters, that the vacuum state of the Universe is metastable and will eventually decay to a Planck-scale true vacuum. In today's Universe this would happen through quantum tunneling, which is very strongly suppressed, but in the early Universe highly energetic non-equilibrium processes and high...
Prof. Valentin Khoze (IPPP Durham University)
Mr. Kimmo Kainulainen (University of Jyväskylä)
The measured Higgs mass value 125 GeV suggests that the standard model may be UV-complete theory up to Planck scale. However, the questions of the nature of the dark matter and of the origin of the baryon asymmetry remain unsolved in the SM. Can these problems be addressed in a simple UV-complete extension of the SM? I will argue that this may be possible in the context of scalar extensions...
Prof. Zygmunt Lalak (University of Warsaw)
I shall discuss the influence of radiative and gravitational corrections to the effective action on vacuum stability of SM-like Higgs sectors. Evolution of domain wall networks created by radiative symmetry breaking and associated production of gravitational waves will be described.
Christophe Grojean (DESY (Hamburg) and Humboldt University (Berlin))
Prof. Stefano Moretti (University of Southampton)
We illustrate the theory and phenomenology of Composite 2-Higgs Doublet Models (C2HDMs) of various Yukawa types based on the global symmetry breaking SO(6)→SO(4)×SO(2). The kinetic term and the Yukawa Lagrangian are constructed in terms of the pseudo Nambu-Goldstone Boson (pNGB) matrix and a 6-plet of fermions under SO(6). The scalar potential is assumed to be the same as that of the...
Mr. Santeri Laurila (Helsinki Institute of Physics)
The standard model is known to be an incomplete description of the nature. Models with an extended Higgs sector are constrained, but not excluded by the discovery of the electrically neutral Higgs boson with a mass of 125 GeV. Charged Higgs bosons (H+) are searched for in proton-proton collisions at CERN LHC in top quark decays tt→H+W-bb (assuming that H+ mass smaller than top quark mass)...
Mr. Andrei Angelescu (LPT Orsay)
At the high luminosity option of the LHC, the current $20-30\%$ errors on the Higgs signal strength measurements will be considerably diminished, reaching values around $10\%$. These errors will be dominated by theoretical uncertainties coming mostly from the production side, namely parton distribution function (PDF), $\alpha_s$, and scale uncertainties. In this talk, I will describe how one...
Mr. Harri Waltari (University of Helsinki)
If R-parity is not conserved, sneutrinos and Higgs bosons can mix. We consider the effects of spontaneous R-parity violation on the Higgs sector. Left-handed sneutrino VEVs need to be small, but right-handed sneutrinos can have sizable VEVs. This can lead to a mixing between the Higgs and the sneutrino. If the sneutrino is lighter than the Higgs, the 125 GeV Higgs mass can be achieved with...
Mr. Hardi Veermae (NICPB, Tallinn)
Classically scale invariant theories may possess fixed points which correspond to dynamically generated physical scales (e.g. the Planck or electroweak scale) and therefore spontaneously break scale invariance. In presence of sources of explicit breaking of scale invariance such as the QCD scale, the fixed point is destabilised and the dynamically generated Planck scale evolves in time....
Dr. Ville Vaskonen (NICPB)
We consider a real scalar singlet field which provides a strong first order electroweak phase transition via its coupling to the Higgs boson, and gives a CP violating contribution on the top quark mass via a dimension 6 operator. We study the correlation between the baryon-to-entropy ratio produced by electroweak baryogenesis, and the gravitational wave signal from the electroweak phase...
Ms. Jorinde van de Vis (Nikhef)
The running of the quartic coupling of the Higgs field creates a second, deep vacuum for the Higgs field. The electroweak vacuum could have survived high scale inflation due to a coupling between the Higgs field and the curvature scalar. During preheating, this coupling generates very efficient production of Higgs modes. We study the effect of these modes on the Higgs potential as well as the...
Mr. Jacopo Fumagalli (Nikhef)
Higgs inflation is arguable the best example of a minimalistic set-up that can explain the inflationary paradigm. At the classical level the model is in perfect agreement with the Planck data. Once quantum effects are considered, new physics is demanded by the consistency of the theory. Thus, even pursuing the minimalistic approach, some threshold corrections need to be added. I will show...
Mr. Yohei Ema (University of Tokyo)
I will discuss the implication of the electroweak (EW) vacuum metastability during the preheating epoch. The EW vacuum may be metastable in light of the current experimental data, and it may have a tension with high-scale inflation. In order to overcome this problem, Higgs-inflaton/-curvature couplings are often introduced. However, after inflation, the additional interaction may destabilize...
We consider inflation within a model framework where the Higgs boson arises as a pseudo-Goldstone boson associated with the breaking of a global symmetry at a scale significantly larger than the electroweak one. We show that such a model evades the shortcomings of the SM Higgs inflation, i.e. the model is stable against quantum corrections and the non-minimal couplings to gravity can be of...
Dr. Stanislav Rusak (University of Helsinki)
Marco Zatta (University of Helsinki)
Prof. Howard Haber (University of California, Santa Cruz)
The most general two-Higgs doublet model (2HDM) includes potentially large sources of flavor changing neutral currents (FCNCs) that must be suppressed in order to yield a phenomenologically viable model. The alignment ansatz postulates that all Yukawa coupling matrices are diagonal when expressed in the basis of mass-eigenstate fermion fields, in which case tree-level Higgs-mediated FCNCs are...
49. Finite temperature dimensional reduction and electroweak baryogenesis in Standard model extensions
Tuomas Tenkanen (University of Helsinki)
Young scientists forum
Electroweak baryogenesis - a scenario to explain observed matter-antimatter asymmetry of the universe - fails in Standard model (SM), because of lack of CP violation and lack of strong 1st order phase transition. Both these shortcomings can be avoided in beyond the SM theories, with extended Higgs sector. Order of phase transition can be analyzed non-perturbatively, by using method of...