The Higgs System in and Beyond the Standard Model

After the discovery of the Higgs boson particle on the 4th of July of 2012 at the Large Hadron Collider, sited at the european CERN laboratory, we are entering in a fascinating period for Particle Physics where both theorists and experimentalists are devoted to fully understand the features of this new particle and the possible consequences for High Energy Physics of the Higgs system both within and beyond the Standard Model of fundamental particle interactions. This paper is a summary of the lectures given at the third IDPASC school (Santiago de Compostela, Feb. 2013, Spain) addressed to PhD students, and contains a short introduction to the main basic aspects of the Higgs boson particle in and beyond the Standard Model.Comment: 62 pages, 31 figures, Lectures of the IDPASC School at Santiago de Compostela, Spain, February 201

Electroweak and Bottom Quark Contributions to Higgs Boson plus Jet Production

This paper presents predictions for jet pseudorapidity (eta) and transverse momentum (p_T) distributions for the production of the Standard Model Higgs boson in association with a high-p_T hadronic jet. We discuss the contributions of electroweak loops and of bottom-quark parton processes to the cross section. The latter arise in the five-flavour scheme. Predictions for the Tevatron and the Large Hadron Collider with 10 TeV collision energy are presented. For Higgs boson masses of 120 GeV, 160 GeV and 200 GeV, we find the maximal effects of the electroweak contributions to the Higgs plus jet p_T and eta distribution to be -14 % and -5.3 %, respectively, for the Tevatron, and -3 % and -2 %, respectively, for the LHC. For the maximal contribution of bottom-quark parton processes to the p_T and eta distribution, we find +3 % and + 2.5 %, respectively, for the Tevatron, and +3.5 % and +3 %, respectively, for the LHC. A separate study of the Higgs + b-jet cross section demonstrates that a calculational approach which respects the hierarchies of Yukawa couplings yields a leading order cross section prediction which is more accurate in the high-p_T regime than conventional approaches.Comment: 25 pages, 14 figure

Not just old and sick - the 'will to health' in later life

The end of the ‘Golden Age’ of welfare capitalism in the 1970s was the prelude to a period of greater individualisation within societies and was accompanied by an increase in the importance of consumption as a way of organising social relations. During the same period there was also an expansion in the discourses aimed at enhancing the government of the autonomous self. One such discourse operates around what has been termed the ‘will to health’: it suggests that health has become a required goal for individual behaviour and has become synonymous with health itself. The generational groups whose lifecourses were most exposed to these changes are now approaching later life. We explore the extent to which social transformations related to risk, consumption and individualisation are reflected in the construction of later-life identities around health and ageing. We examine how the growth in health-related ‘technologies of the self’ have fostered a distinction between natural and normal ageing, wherein the former is associated with coming to terms with physical decline and the latter associated with maintaining norms of self-care aimed at delaying such decline. Finally, we consider anti-ageing medicine as a developing arena for the construction of later-life identities and discuss the implications of the social changes for researching later life

Error threshold in simple landscapes

We consider the quasispecies description of a population evolving in both the "master sequence" landscape (where a single sequence is evolutionarily preferred over all others) and the REM landscape (where the fitness of different sequences is an independent, identically distributed, random variable). We show that, in both cases, the error threshold is analogous to a first order thermodynamical transition, where the overlap between the average genotype and the optimal one drops discontinuously to zero.Comment: 10 pages and 2 figures, Plain LaTe

New Mechanism of Flavor Symmetry Breaking from Supersymmetric Strong Dynamics

We present a class of supersymmetric models in which flavor symmetries are broken dynamically, by a set of composite flavon fields. The strong dynamics that is responsible for confinement in the flavor sector also drives flavor symmetry breaking vacuum expectation values, as a consequence of a quantum-deformed moduli space. Yukawa couplings result as a power series in the ratio of the confinement to Planck scale, and the fermion mass hierarchy depends on the differing number of preons in different flavor symmetry-breaking operators. We present viable non-Abelian and Abelian flavor models that incorporate this mechanism.Comment: 24 pp. LaTe

Limitation of Trypanosoma brucei parasitaemia results from a combination of density-dependent parasite differentiation and parasite killing by the host immune response

In the bloodstream of its mammalian host, the "slender" form of Trypanosoma brucei replicates extracellularly, producing a parasitaemia. At high density, the level of parasitaemia is limited at a sublethal level by differentiation to the non-replicative "stumpy" form and by the host immune response. Here, we derive continuous time equations to model the time-course, cell types and level of trypanosome parasitaemia, and compare the best fits with experimental data. The best fits that were obtained favour a model in which both density-dependent trypanosome differentiation and host immune response have a role in limiting the increase of parasites, much poorer fits being obtained when differentiation and immune response are considered independently of one another. Best fits also favour a model in which the slender-to-stumpy differentiation progresses in a manner that is essentially independent of the cell cycle. Finally, these models also make the prediction that the density-dependent trypanosome differentiation mechanism can give rise to oscillations in parasitaemia level. These oscillations are independent of the immune system and are not due to antigenic variation

Iron architecture in Britain and America (1706-1880): with special reference to the development of the portable building

"Ignorance, it has been said, is a prerequisite of the historian. This is particularly true of anyone who attempts to survey, however super- ficially, the achievements of the nineteenth century. The material at his hand is so overwhelming in bulk and so bewildering in texture and colour, that all he can do is pick over the tumbled debris of this vast quarry, and select at random a few stones which, when held up to the light, may reveal something of the nature of the complex mass from which they came. "(H. Casson, An Introduction to Victorian Architecture, 1948).As little recent research had been done on the 'portable building' a large part of my study was concentrated on this subject. It soon became obvious that the work of Andrew Handyside of Derby was of particular interest in this field and I was persuaded to publish a paper on their work separately.I have not, therefore, included this material in the main body of the thesis and have only referred to it where the text demanded.The major departure from a generally chronological account was the decision to single out, for reasons of clarity, the account of the contribution of iron to the development of a new style of architecture.Because many of the buildings examined in the thesis may be unfamiliar, I thought it sensible to include a rather large number of plates. This has had the beneficial effect of being able to reduce the length of descriptions of these buildings and to simplify the technical explanations that were necessary. In addition much of the illustrated material is only available in 19th century books, pamphlets and journals, many of which are scarce and therefore difficult to consult.A precise definition of iron architecture is almost impossible. As it was used in the 19th century it referred to the use of iron in a building as its major structural and constructional material and to the use of the material where it had a.radical influence on the appearance of the building. I have followed this general meaning and therefore have excluded from the study iron balconies, railings, gates, and other examples of ornamental ironwork that were added to buildings. In addition engineering structures, such as bridges, piers, and lighthouses, have not been included unless they had a direct effect on the use of iron in architecture

Bloch-Nordsieck Violation in Spontaneously Broken Abelian Theories

We point out that, in a spontaneously broken U(1) gauge theory, inclusive processes, whose primary particles are mass eigenstates that do not coincide with the gauge eigenstates, are not free of infrared logarithms. The charge mixing allowed by symmetry breaking and the ensuing Bloch-Nordsieck violation are here analyzed in a few relevant cases and in particular for processes initiated by longitudinal gauge bosons. Of particular interest is the example of weak hypercharge in the Standard Model where, in addition, left-right mixing effects arise in transversely polarized fermion beams.Comment: 4 pages, 1 figur