284 research outputs found
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The global economic crisis and FDI flows to emerging markets
For the first time ever, emerging markets are set to attract more FDI inflows than developed countries in 2009. This perspective examines this prospect, based on an analysis of the severe downturn of investment flows worldwide this year
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FDI to the UK will remain robust post-Brexit
The UK’s expected departure from the EU has led to predictions of a negative impact on inward FDI. Strong economic performance and FDI inflows have confounded short-term expectations. The UK’s traditional location advantages, business survey results and appropriate government policies suggest that FDI will remain robust in the long term
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To what extent has FDI benefited the transition economies of Central and Eastern Europe?
An empirical estimate shows that FDI has had only a weak positive impact on GDP growth in transition economies of Central and Eastern Europe. Convergence with the developed EU is slowing and these countries will need to develop growth strategies that do not depend overwhelmingly on FDI
The seesaw path to leptonic CP violation
Future experiments such as SHiP and high-intensity colliders will
have a superb sensitivity to heavy Majorana neutrinos with masses below .
We show that the measurement of the mixing to electrons and muons of one such
state could imply the discovery of leptonic CP violation in the context of
seesaw models. We quantify in the minimal model the CP discovery potential of
these future experiments, and demonstrate that a 5 CL discovery of
leptonic CP violation would be possible in a very significant fraction of
parameter space.Comment: An error has been fixed, main conclusions unchange
Phenomenology of low-scale Seesaw Models
All the observed particles are well accommodated in the Standard Model, together with the basic forces. However, there are both experimental and theoretical
hints that the Standard Model can not be a complete theory and that New Physics is needed.
Some of the theoretical problems are:
i) The flavor-puzzle, i.e., why are there three copies of particles differing only by their mass. Most of the free parameters in the Standard Model are linked to this puzzle.
They have been measured, but their values do not follow any clear pattern and their origin remains elusive.
ii) The strong CP problem, that is, why the CP symmetry is conserved in the strong interactions in the Standard Model, which is not ensured by any gauge symmetry.
iii) How to combine quantum mechanics with general relativity, since the attempts to do this lead to non-renormalizable theories. Furthermore,
gravity necessarily introduces a new scale, the Planck scale, which leads to the hierarchy problem.
iv)The hierarchy problem: why is the electroweak scale so much smaller than the Planck mass. If there were new particles heavier than the electroweak scale, their coupling with the Higgs boson
would induce quantum corrections to the Higgs mass naturally of the order of those higher masses.
On the other hand, there are also experimental hints for physics beyond the Standard Model :i) Neutrinos were assumed massless in the SM but the well established phenomena of neutrino oscillations implies that they are massive, and the SM has to be modified.
ii)The dominance of baryons over antibaryons in the Universe can not be explained within the SM. iii) The origin of Dark Matter that accounts for 25 % of the gravitating matter in the Universe. A solution to this problem might lie in the existence of a new weakly-interacting particle that is not yet discovered.
iv) The dark energy, a force responsible for the Universe's accelerating expansion, contributes to 70% of the total energy in the Universe. The nature of this energy is unknown.
Two of the mentioned hints, non-zero neutrino masses and the baryon asymmetry, will be addressed in the thesis in the context of the low-scale Seesaw Models.
Low-scale Seesaw Models are the minimal extensions of the Standard Model (SM) that can explain neutrino masses and are potentially testable in the next generation experiments.
These models add two or three extra singlet (sterile) fermions to the SM, with masses below the electroweak scale. The main goal of this thesis is to study the impact of these extra states in the Early Universe.
The thesis is divided in two parts, the first one covers a lengthy introduction and background material for understanding the original results of this work.
The plan of this thesis is as follows:
In Chapter I we motivate the need for new physics beyond the Standard Model.
In Chapter II we give a brief review of the Standard Model, the theory that has been experimentally confirmed at the highest energies probed by current collider experiments. On the other hand, neutrinos were assumed massless in the Standard Model while oscillation experiments have demonstrated that neutrinos have non vanishing masses. In Chapter III we give a
list of the most popular extensions of the Standard Model that can explain light neutrino masses.
In Chapter IV, we summarize what is known about the lepton flavour sector of the Standard Model,
focusing particularly on the phenomenology of the low-scale Seesaw Models. In Chapter V we give the motivation for the mass scale of the extra fermions in these models, the
parametrization of the models and the current and future experimental constraints on the model parameters.
In Chapter VI we give a brief review of the Standard Cosmological Model, and in Chapter VII we discuss the thermodynamics of the Early Universe plasma. In Chapter VIII we
focus on the sterile neutrino evolution before the electroweak phase transition, where they can seed the observed matter-antimatter asymmetry in the Universe. The evolution of the sterile neutrinos
after the electroweak phase transition and their impact on the cosmological parameters is given in Chapter IX.
Finally, in Chapter X we summarize the main scientific results in this work, divided in four publications, that are reproduced in full in Part II of the thesis
The Landscape of Hohenschönhausen, Berlin and Its Influence on Modernist Single-Family Housing
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英国的FDI将在其脱欧后保持强劲态势
The UK’s expected departure from the EU has led to predictions of a negative impact on inward FDI. Strong economic performance and FDI inflows have confounded short-term expectations. The UK’s traditional location advantages, business survey results and appropriate government policies suggest that FDI will remain robust in the long term
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中东欧转型期经济体在何种程度上受益于FDI?
An empirical estimate shows that FDI has had only a weak positive impact on GDP growth in transition economies of Central and Eastern Europe. Convergence with the developed EU is slowing and these countries will need to develop growth strategies that do not depend overwhelmingly on FDI
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