# Helsinki Higgs Forum

14-16 December 2016
Physicum
Europe/Helsinki timezone
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## Contribution List

Displaying 35 contributions out of 35
Session: Higgs at colliders / precision calculations
Track: Higgs at colliders / precision calculations
I shall discuss various criteria for having CP violation in the 2HDM, expressed in terms of physical quantities like masses and couplings.
Presented by Prof. Per OSLAND on 14 Dec 2016 at 14:30
Session: Higgs model building
Track: Higgs model building
Presented by Christophe GROJEAN on 16 Dec 2016 at 10:30
Session: Young scientists forum
Track: Young scientists forum
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 that ... More
Presented by Mr. Jacopo FUMAGALLI on 16 Dec 2016 at 15:10
Session: Higgs and Cosmology
Track: Higgs and cosmology
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.
Presented by Prof. Zygmunt LALAK on 15 Dec 2016 at 17:00
Session: Higgs and Cosmology
Track: Higgs and cosmology
*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 implementing Hi ... More
Presented by Jose R. ESPINOSA on 15 Dec 2016 at 14:00
Session: Higgs and Cosmology
Track: Higgs and cosmology
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 of th ... More
Presented by Mr. Kimmo KAINULAINEN on 15 Dec 2016 at 16:30
Session: Young scientists forum
Track: Young scientists forum
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 transition ... More
Presented by Dr. Ville VASKONEN on 16 Dec 2016 at 14:50
Session: Young scientists forum
Track: Young scientists forum
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 the E ... More
Presented by Mr. Yohei EMA on 16 Dec 2016 at 15:20
Session: Higgs at colliders / precision calculations
Track: Higgs at colliders / precision calculations
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 Planck ma ... More
Presented by Prof. Bernd KNIEHL on 14 Dec 2016 at 12:00
Session: Young scientists forum
Track: Young scientists forum
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. However, q ... More
Presented by Mr. Hardi VEERMAE on 16 Dec 2016 at 14:40
Session: Young scientists forum
Track: 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 dimensional ... More
Presented by Tuomas TENKANEN
Presented by Abdelhak DJOUADI on 14 Dec 2016 at 11:30
Session: Young scientists forum
Track: Young scientists forum
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 rather ... More
Presented by Mr. Harri WALTARI on 16 Dec 2016 at 14:20
Session: Higgs at colliders / precision calculations
Track: Higgs at colliders / precision calculations
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.
Presented by Prof. Sven-Olaf MOCH on 14 Dec 2016 at 14:00
Session: Young scientists forum
Track: Young scientists forum
Presented by Dr. Stanislav RUSAK on 16 Dec 2016 at 16:10
Session: Higgs and Cosmology
Track: Higgs and cosmology
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 data. ... More
Presented by Dr. Marieke POSTMA on 15 Dec 2016 at 14:30
Session: Higgs and flavor
Track: Higgs and flavor
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 wi ... More
Presented by Dr. Miha NEMEVŠEK on 15 Dec 2016 at 10:00
Session: Young scientists forum
Track: Young scientists forum
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 ener ... More
Presented by Ms. Jorinde VAN DE VIS on 16 Dec 2016 at 15:00
Session: Higgs and Cosmology
Track: Higgs and cosmology
Presented by Prof. Valentin KHOZE on 15 Dec 2016 at 16:00
Presented by Niko KOIVUNEN on 16 Dec 2016 at 14:30
Session: Young scientists forum
Track: Young scientists forum
Presented by Marco ZATTA on 16 Dec 2016 at 16:20
Session: Higgs model building
Track: Higgs model building
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 eli ... More
Presented by Prof. Howard HABER on 16 Dec 2016 at 16:30
Session: Higgs model building
Track: Higgs model building
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 coup ... More
Presented by Prof. Arthur HEBECKER on 15 Dec 2016 at 12:00
Session: Young scientists forum
Track: Young scientists forum
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 or ... More
Presented by Tommi TENKANEN on 16 Dec 2016 at 16:00
Session: Experimental status
Track: Experimental status
Non-minimal Higgs: experimental overview of searches with ATLAS and CMS detectors at the LHC.
Presented by Dr. Ljiljana MORVAJ on 14 Dec 2016 at 10:30
Session: Young scientists forum
Track: Young scientists forum
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 can s ... More
Presented by Mr. Andrei ANGELESCU on 16 Dec 2016 at 14:10
Session: Higgs and flavor
Track: Higgs and flavor
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.
Presented by Martti RAIDAL on 14 Dec 2016 at 16:30
Session: Higgs model building
Track: Higgs model building
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 hierarch ... More
Presented by Prof. Graham ROSS on 15 Dec 2016 at 11:30
Session: Young scientists forum
Track: Young scientists forum
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) and ... More
Presented by Mr. Santeri LAURILA on 16 Dec 2016 at 14:00
Session: Experimental status
Track: Experimental status
Presented by Josh BENDAVID on 14 Dec 2016 at 10:00
I will discuss the Inert Doublet Model, which contains SM-like Higgs Doublet and Dark Doublet, and its extension with a complex singlet.
Presented by Maria KRAWCZYK on 14 Dec 2016 at 15:00
Session: Higgs and flavor
Track: Higgs and flavor
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.
Presented by Prof. Gustavo BRANCO on 14 Dec 2016 at 16:00
Session: Higgs model building
Track: Higgs model building
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 Elementary ... More
Presented by Prof. Stefano MORETTI on 16 Dec 2016 at 11:30
Session: Higgs and flavor
Track: Higgs and flavor
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 breakdown ... More
Presented by Margarida (Gui) Nesbitt REBELO on 15 Dec 2016 at 10:30
Session: Higgs and Cosmology
Track: Higgs and cosmology
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 spacetim ... More
Presented by Prof. Arttu RAJANTIE on 15 Dec 2016 at 15:00