Sneutrino-antisneutrino oscillations at colliders

Modern elementary particle physics is based on quantum field theories. Currently, our understanding is that, on the one hand, the smallest structures of matter and, on the other hand, the composition of the universe are based on quantum field theories which present the observable phenomena by describing particles as vibrations of the fields. The Standard Model of particle physics is a quantum field theory describing the electromagnetic, weak, and strong interactions in terms of a gauge field theory. However, it is believed that the Standard Model describes physics properly only up to a certain energy scale. This scale cannot be much larger than the so-called electroweak scale, i.e., the masses of the gauge fields W^+- and Z^0. Beyond this scale, the Standard Model has to be modified. In this dissertation, supersymmetric theories are used to tackle the problems of the Standard Model. For example, the quadratic divergences, which plague the Higgs boson mass in the Standard model, cancel in supersymmetric theories. Experimental facts concerning the neutrino sector indicate that the lepton number is violated in Nature. On the other hand, the lepton number violating Majorana neutrino masses can induce sneutrino-antisneutrino oscillations in any supersymmetric model. In this dissertation, I present some viable signals for detecting the sneutrino-antisneutrino oscillation at colliders. At the e-gamma collider (at the International Linear Collider), the numbers of the electron-sneutrino-antisneutrino oscillation signal events are quite high, and the backgrounds are quite small. A similar study for the LHC shows that, even though there are several backrounds, the sneutrino-antisneutrino oscillations can be detected. A useful asymmetry observable is introduced and studied. Usually, the oscillation probability formula where the sneutrinos are produced at rest is used. However, here, we study a general oscillation probability. The Lorentz factor and the distance at which the measurement is made inside the detector can have effects, especially when the sneutrino decay width is very small. These effects are demonstrated for a certain scenario at the LHC.

Euclideanization of Majorana and Weyl Fermions

A continuous procedure is presented for euclideanization of Majorana and Weyl fermions without doubling their degrees of freedom. The Euclidean theory so obtained is SO(4) invariant and Osterwalder-Schrader (OS) positive. This enables us to define a one-complex parameter family of the N=1 supersymmetric Yang-Mills (SSYM) theories which interpolate between the Minkowski and a Euclidean SSYM theory. The interpolating action, and hence the Euclidean action, manifests all the continous symmetries of the original Minkowski space theory.

Relation between effective atomic charge and chemical shifts in X-ray absorption spectra of transition-metal compounds

Chemical shifts of K absorption discontinuities, Delta E, of several manganese, iron and cobalt oxides with the metal in the formal oxidation states between +2 and +4, have been measured. These data, together with data in the literature on other compounds of these metals, can be fitted into the expression Delta E=aq+bq2, where q is the effective atomic charge on the metal. Theoretical considerations also support this functional relationship between Delta E and q.

The role of p73 in cancer – a pathway towards more effective cancer therapy

The p53-family consists of three transcription factors, p53, p73 and p63. The family members have similar but also individual functions connected to cell cycle regulation, development and tumorigenesis. p53 and p73 act mainly as tumor suppressors. During DNA damage caused by anticancer drugs or irradiation, p53 and p73 levels are upregulated in cancer cells leading to apoptosis and cell cycle arrest. p53 is mutated in almost 50 per cent of the cancers, causing the cancer cells unable to undergo cell death. Instead, p73 is rarely mutated in cancer cells and because of that could be more viable target for anticancer therapy. The network surrounding the regulation of p73 is extensive and has several potential targets for cancer therapy. One of the most studied is Itch ligase, the negative regulator of p73 levels. Gene therapy directed towards knockdown of Itch ligase is a potential approach but in need for more in vivo proof. p73 has two isoforms, transactivating TA-forms and dominant-negative ΔN-forms. The specific regulation of these isoforms could also offer a possible way for more effective cancer treatment. The literature work includes information of structures, isoforms, functions and possible therapeutic targets of p73. Also the main therapeutic approaches to date are introduced. The experimental part is based on transfection and cytotoxicity studies done e.g. in pancreatic cancer cells (Mia PaCa-2, PANC1, BxPc-3 and HPAC). The aim of the experimental work was to optimize the conditions for effective transfection with DAB16 dendrimer nanoparticles and to measure the cytotoxicity of plain dendrimers and DAB16-pDNA complexes. Also the protein levels of p73 and Itch ligase were measured by Western blotting. The work was done as a part of a bigger project, which was aiming to down regulate Itch ligase (negative regulator of p73) by siRNA/shRNA. Tranfection results were promising, showing good transfection efficacy with DAB16 N/P30 in pancreatic cancer cells (except in BxPc-3). Pancreatic cancer cells showed recovery in 3 days after they were exposed to plain dendrimer solution or to DAB16-pDNA. Measurement of protein levels by Western blotting was not optimal and the proposals for the improvement regarding e.g. the gels and the extracted protein amounts have been done.

Solitons of Coupled Scalar Field Theories in Two Dimensions

This work offers a method for finding some exact soliton solutions to coupled relativistic scalar field theories in 1+1 dimensions. The method can yield static solutions as well as quasistatic "charged" solutions for a variety of Lagrangians. Explicit solutions are derived as examples. A particularly interesting class of solutions is nontopological without being either charged or time dependent.

Path integral quantisation of topological field theories

Conditions for quantum topological invariance of classically topological field theories in the path integral formulation are discussed. Both the three-dimensional Chern-Simons system and a Witten-type topological field theory are shown to satisfy these conditions.

Mean-field theories of Hubbard and t-J models

We report novel results obtained for the Hubbard and t-J models by various mean-field approximations.

Gauge-invariant reformulation of theories with second-class constraints

Given a classical dynamical theory with second-class constraints, it is sometimes possible to construct another theory with first-class constraints, i.e., a gauge-invariant one, which is physically equivalent to the first theory. We identify some conditions under which this may be done, explaining the general principles and working out several examples. Field theoretic applications include the chiral Schwinger model and the non-linear sigma model. An interesting connection with the work of Faddeev and Shatashvili is pointed out.

Ale jaskkot eatnigiella : Alkuperäiskansaliikkeen ja saamen kielen merkitys saamelaisten identiteetille

This study examines the Sámi people and the construction of the Sámi identity and the role of language in the cross-border Sámi movement within the context of the international indigenous movement and discourse between 1962 and 2008. The Sámi movement began as a reaction to state assimilation policies. This led to the birth of indigenous processes strengthening the Sámi cultures and languages. Activities across borders and the ethnopolitical processes in each of the Nordic countries in question also formed the basis of the internationalization of the Sámi people. The discourse on indigenous peoples has grown into a question of human rights, which is examined in different national and international contexts. The study is based on ethnographic data that has been collected via interviews, questionnaires and participant observation with the researched people in different meetings and events. Archive and newsprint material are also used. The approach of the study is auto-ethnographic. The post-colonial theories used in the study strive to destabilize power relations and the distinctions of otherness produced by colonialism, and to reclaim both one's own culture and language in the context of the indigenous movement. A standard model for this type of approach was created by Edward W. Said in his 1978 work Orientalism. The central concepts of the analysis are decolonization, otherness, ethnicity and identity. The dissertation consists of four published articles and an introduction. The subject matter is analyzed on three levels: global, European and Nordic. On the global level, the results demonstrate that the indigenous movement has constructed a new understanding of indigenousness with new rights. International treaties have facilitated the unification of new concepts and rights, such as the right to self-determination and language, also helping in transforming them into rights of the Sámi people on a national level. On the Nordic level, aligning the Sámi culture with indigenous discourse became significant for the process of developing the Sámi identity in the Sámi movement. In this process, the Sámi movement made use of Sámi languages in order to mobilize groups of people and to construct relatedness between different Sámi groups. The realization that one s own language is significant to one's culture has resulted in recreating the vitality, visibility and the legitimation of language in society more generally. The migration of the Sámi people from their traditional territories to increasingly multi-ethnic urban areas alters one's relationship to one's own community as the relationship to cultural traditions changes. Among the urban Sámi, who form a group of ‘new Sáminess’, linguistic discrimination and assimilation continue because of the lack of legislative and other effective language policy measures to promote the learning and use of the Sámi language.

Solvation dynamics in a Brownian dipolar lattice. Comparison between computer simulation and various molecular theories of solvation dynamics

Several recent theoretical and computer simulation studies have considered solvation dynamics in a Brownian dipolar lattice which provides a simple model solvent for which detailed calculations can be carried out. In this article a fully microscopic calculation of the solvation dynamics of an ion in a Brownian dipolar lattice is presented. The calculation is based on the non‐Markovian molecular hydrodynamic theory developed recently. The main assumption of the present calculation is that the two‐particle orientational correlation functions of the solid can be replaced by those of the liquid state. It is shown that such a calculation provides an excellent agreement with the computer simulation results. More importantly, the present calculations clearly demonstrate that the frequency‐dependent dielectric friction plays an important role in the long time decay of the solvation time correlation function. We also find that the present calculation provides somewhat better agreement than either the dynamic mean spherical approximation (DMSA) or the Fried–Mukamel theory which use the simulated frequency‐dependent dielectric function. It is found that the dissipative kernels used in the molecular hydrodynamic approach and in the Fried–Mukamel theory are vastly different, especially at short times. However, in spite of this disagreement, the two theories still lead to comparable results in good agreement with computer simulation, which suggests that even a semiquantitatively accurate dissipative kernel may be sufficient to obtain a reliable solvation time correlation function. A new wave vector and frequency‐dependent dissipative kernel (or memory function) is proposed which correctly goes over to the appropriate expressions in both the single particle and the collective limits. This form is expected to lead to better results than all the existing descriptions.