THEORETICAL PHYSICS OF HIGH-ENERGY

Author: CANOA ROMÁN VERÓNICA.
Year: 2004.
University: SANTIAGO DE COMPOSTELA [www.usc.es].
Place of defense: FACULTAD DE FÍSICA.
Place of preparation: FACULTAD DE FÍSICA.

Summary: In studying cosmic rays from the cascades are weather problems. These are given by the uncertainty of the models hadrónicos because on the one hand to energies at which properties are mediated interactions hadrónicas accelerator become up to six orders of magnitude lower, on the other hand, the region does not usually forward far be accelerators, however is responsible for most of the characteristics of the cascade. What was done in the working thesis was to study the parameters of the cascade is affected when considering different models hadrónicos. And on the other hand it is proposed the possibility of measuring parameters of the models hadrónicos from waterfalls atmósfericas. More specifically, models hadrónicos deemed to see the effects that will occur in atmospheric cascades are: * Two models hadrónicos that predict collective phenomena. One model predicts that fusion of strings reduction of the multiplicity of fragmentation in the region. * Consider the theory of chiral condensate disoriented (DCC). It is a collaborative model in the production of piones, which reduces the fraction of piones loaded respect to neutral. * Variamos section effective fotoproducción based on two proposals, one that grows with energy and another to see which pervades changes in cascades. * Finally we study what happens to vary section effective as pioneers and will affect waterfalls, and the possibility of measurement. The study of all these models and the effect they produce in cascades opens the possibility to discriminate in favor of some others.

Author: BRONCANO BERROCAL ALICIA.
Year: 2004.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: This work is specialized in the model seesaw (seesaw in English) can provide an explanation natural and simple lightness neutrino .. To establish whether this is the theory chosen by nature, it is important to ascertain its implications at low energy. In this work we analyzed ellagrangiano cash valid at low energies. This has been calculated by integrating the fields of heavy neutrinos and the consequent expansion of its propagator in a power series in 1 / M. The result is an infinite number of operators gauge invariant dimension d minor 4 and trained by SM fields. We have submitted the minimum set of operators dimension higher than are necessary to establish a connection between the physical parameters generic low energy and the parameters of the seesaw. We have found that the number of such infinite series when the match is truncated to order 1/M2 for a number of neutrinos heavy equaled less than the number of generations of leptones light. The first term dellagrangiano cash is the sole operator of d = 5 which gives rise to the coefficient matrix of Majorana mass m neutrinos levógiros. By rewriting the theory in terms of autoestados, non-diagonal terms in flavor appear in the acoplo of leptones to bosón W. The second component dellagrangiano cash is the operator of d = 6 obtained in the integration level tree. After the breakup of the electroweak symmetry, the coefficient of this operator results in a matrix that contains kinetic non-diagonal terms in flavor neutrinos levógiros. The physical impact can be transferred to the acopios of neutrinos with the gauge bosons using a rotation at the base where the kinetic energy is diagonally. In this way, you get a matrix mixing léptonica not uniform. In order 1/M2, the operator of d = 6 does not alter the effects of operator d = 5. The dependence of the coefficients of the operators of d = 5 d = 6en parameters seesaw, has enabled us to determine the connection between theory and the theory effectively complete. Investing definitions can express my matrices high energy YyM in terms of the parameters of low energy. In this paper, we found this relationship. The expressions encountered in YyM depend explicitly on the basis of low energy chosen for my. For example, when my parent are at their base autoestados, you get an array of neutrino masses for heavy M that is neither real nor diagonally. It is therefore necessary to rotate MyYa based autoestados M. This complicated step is very important since it allows you asymmetry CP leptogénesis depending on parameters of low energies. We have derived the expression of asymmetry in the case of heavy neutrino with a hierarchical structure mass. Several consequences of interest are deducted from this expression. (1) The phases of CP leptogénesis depend on a complex form of the stages of my. This means that even if Im (m) = O, the asymmetry CP leptogénesis may be different from zero. (2) For eigenvalues degenerate mo of the CP asymmetry becomes zero. In the case where both parent low energy have their eigenvalues degenerate, then M also has its eigenvalues degenerate. In addition to the operator d = 6 obtained at the tree, other operators d = 6 appear in Lagrangian Low power as a result of the renormalización operator level tree. We have studied the contribution of these additional operators to renormalización of the matrix mixing léptonica. The analysis has been done on the theory effective order 1/M2, including the main diagonal corrections not in taste due to two insertions of the operator d = 5 or operator d = 6 obtained at the tree.

Author: Béjar Latonda Santiago.
Year: 2005.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: Departamento de Física, Grupo de Física Teórica.
Place of preparation: Departamento de Física, Grupo de Física Teórica.

Author: Picon Ponce Moises Rogelio.
Year: 2005.
University: VALENCIA [www.uv.es].
Place of defense: Facultad de Física.
Place of preparation: Departamento de Fisica Teorica.

Summary: The thesis is divided into four parts. The first part describes the method of expansions to obtain superálgebras Lie from a given, which unlike other methods known as contractions and deformations algebras, generally leads to larger algebras that original. This method includes the method of contractions as particular case. The extension of the method of expansions in the case of free differential algebras allows building supergravedades Chern-Simons, and in particular allows us to the formulation of a new supergravity Chern-Simons in D = 11 from algebra osp (1 | 32 ). The second part examines the possible structure of the underlying gauge of supergravity CJS in eleven dimensions. It shows in detail the structure composed of tres-forma of multiplet supergravity A_3, extending the previous results of D'Auria and Fré, and emphasizing the equivalence of the problem with the trivialization of a cuatro-cociclo for cohomología of algebra standard supersymmetry in eleven dimensions in a family of superálgebras bigger. We discuss their possible consequences dynamics, which are considered the property of the action of supergravity first order with a field A_3 compound and shows that there is a set of gauge symmetry that ensures that the extra degrees of freedom of this theory are same as when one considers the field A_3 as crucial. These considerations on the composite structure of A_3 are another application of the idea that there is a correspondence biunívoca between the coordinates of superespacio widespread and fields of the theory. Such considerations suggest that there is a possible embebimiento of supergravity in D = 11 in a theory defined in a superespacio Blew. The third part is an action proposed for a model supercuerda a superespacio extended preserving this model 30/32 supersimetrías, and that may be formulated through two supertwistors. The concept of twistor described in more detail in the last part, which was followed by widespread methods of theories two times. This generalization, consisting of a widespread transformation Penrose, lets you write with a single twistor many types of particles to the relativistic particles with no mass, such as a particle or a massive particle in a curved space. Beyond the definition of particles through twistors also define twistors for a phase space that includes extra degrees of freedom, which could lead to new applications.

Author: Hoyos Badajoz Carlos.
Year: 2005.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: Dep. Fís. Teór.Fac. de Cien. UAM.
Place of preparation: Departamento de Física Teórica.

Summary: Background and current status: One of the current issues most important research in the field of Theoretical Physics of High Energies is the correspondence between theories and gauge theories of gravity. According to the correspondence, the two theories are equivalent under a proper identification of dual quantities. The duality plays a very important role that the group's gauge range is very large (big N). For the most part, the duality has been studied in the limit where N is infinite (planar). However, although corrections type 1 / N could change drastically equivalence, not yet know very well how to implement them. Moreover, the duality is established when the gauge theory is acoplo strong, so that the curvature of dual gravitational is small. In this way, property not perturbativas that could not be studied analytically in gauge theory, can be extracted from its dual gravitational. Currently known models with a variety of properties, including confinement, quarks, etc., and it is thought that in this way you can get to describe the physics of strong interactions. There is great interest and thus establish how the various features of the gauge theory are codified in the dual geometry. Another line of research is related to the planar equivalence between theory and supersymmetric theories that are not. Many of the properties not perturbativas, for which there is no rigorous description in the case not supersimétrico, can be described exactly thanks to supersymmetry. The equivalence means that the results could be moved immediately from one another. However, the validity of the equivalence level not perturbativo is not completely established. Contents: First, it examines how the geometry of classical theories garvitatorias is modified by the introduction of deformations multitraza in a gauge theory is that its dual holographic. It is seen that this corresponds to a modification of the boundary conditions for the theory of gravity. This is justified from the point of view of the gauge theory thanks to the collective properties of the large-N theory, which allows an approximation of field half or Hartree. It looks at one example in which the deformation of multitraza alter the phase diagram of location between D4 and D3 branas. Secondly, it builds a model that implements gravitational physics of the large-N axial anomaly. It chooses a geometry properties with the appropriate containment, introducing an angle using vacuum flow and introduces without quark mass branas test. It is found that the results are in accordance with the formula Witten-Veneziano, which relates topological susceptibility of the gauge theory with the mass of eta '. Finally, it examines the validity of the equivalence planar finite volume, where the theory is acoplo weak and can be applied methods perturbativos and semiclásicos. In the bull appears moduli space, which appears a potential 1-loop in non supersymmetric theories. One sees that the potential violates equivalence planar on certain points of the moduli space of matching minimums. When attempting to remove the moduli space conditions by introducing non-periodic gaps not supersymmetric theories do not match those of supersimeétricas. Calculations semiclásicos of transitions between different gaps also give different results for certain elements of matrix operators fermiónicos. We conclude that equivalence Planar is a dynamic non-trivial issue.

Author: ZSEMBINSZKI GABRIEL SEBASTIAN.
Year: 2006.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: UNIVERSIDAD AUTÓNOMA DE BARCELONA.
Place of preparation: INSTITUTO DE FÍSICA DE ALTA ENERGÍAS.

Summary: The most successful scientific theory today about the origin and evolution of the universe is known as the standard Big Bang model, which is one of the most ambitious intellectual constructions of humanity. It is based on two consolidated branches of theoretical physics, namely, the theory of General Relativity and the Standard Model of particle physics, and is able to make robust predictions, such as the expansion of the universe, the existence of the cosmic microwave background radiation and the relative primordial abundance of light elements. Some of the theoretical predictions have already been confirmed by very precise observations. According to the standard Big Bang cosmology, the early universe consisted of a very hot and dense plasma that continuosly expanded and cooled up to the present, giving place to a series of cosmological phase transitions. Given that the energies of the early universe were much higher than those reached in terrestrial experiments, the study of the early universe might give us important information about new interactions and new particles, opening new directions for extending the Standard Model of particle physics. As mentioned above, during the expansion of the universe, different phase transitions occurred, which left their imprint on the present state of the universe. Observations suggest that during a very early phase transition the universe suffered a stage of accelerated expansion, known as inflation. Although inflation is not included in the standard cosmology, it is able to solve in a simple and elegant manner almost all of the shortcomings related to the standard Big Bang model, ans should be taken into account in any possible extension of the theory. Observations also reveal evidence of the existence of two unknown forms of energy, i.e., dark matter and dark energy. Dark matter is a form of non-relativistic and non-baryonic matter, which can only be detected indirectly, through its gravitational interactions with normal matter. Dark energy is a kind of substance with negative pressure, which started to dominate recently and causes the accelerated expansion of the universe. In this PhD Thesis, I present a few original models proposed to solve some of the shortcomings of the standard cosmology, as possible extensions of the Big Bang model. Some of these models introduce new symmetries and fields in order to explain inflation and dark energy and/or dark matter in a unified description. One of the models is proposed for explaining the dark energy of the universe, by means of a new scalar field oscillating in a potential.

Author: Redondo Martín Javier.
Year: 2006.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: Instituto de física de Altas energías.
Place of preparation: Departamento de física teórica/Instituto de física de altas energías.

Summary: Collaboration PVLAS recently announced the observation dicroismo and birefringencia of vacuum in the presence of an intense magnetic field. Both effects are typical predictions of the existence of light particles, such as axión, interact with the electromagnetic field. The intensity of this interaction inferred by the actions of PVLAS is strongly excluded by astrophysicists and arguments by the so-called Helioscopios experiments that attempt to detect these particles because, as neutrinos would be produced in large numbers in the interior of the Sun. This thesis presents models where the limits astrophysicists lose all its power, allowing the existence of the particle PVLAS. All have in common the existence of additional particles, in particular parafotones and particulate milicargadas. It also conducts an independent review of models indicating that the reconciliation of PVLAS with astrophysics implies the existence of new physics at low energies, which can be accessed precision experiments. Finally it is shown that in the event that a new particle has positive parity, the more exclusive limits do not come from astrophysics but experiments that test the validity of the law of universal gravitation or the Casimir effect.