The 125 GeV boson: A composite scalar?

Assuming that the 125 GeV particle observed at the LHC is a composite scalar and responsible for the electroweak gauge symmetry breaking, we consider the possibility that the bound state is generated by a non-Abelian gauge theory with dynamically generated gauge boson masses and a specific chiral symmetry breaking dynamics motivated by confinement. The scalar mass is computed with the use of the Bethe-Salpeter equation and its normalization condition as a function of the SU(N) group and the respective fermionic representation. If the fermions that form the composite state are in the fundamental representation of the SU(N) group, we can generate such light boson only for one specific number of fermions for each group. In the case of small groups, like SU(2) to SU(5), and two fermions in the adjoint representation we find that is quite improbable to generate such light composite scalar.Comment: 24 pages, 5 figures, discussion extended, references added; version to appear in Phys. Rev.

The medium on the stage: Trance and performance in nineteenth-century spiritualism

This is an Accepted Manuscript of an article published in Early Popular Visual Culture on 06 Sep 2011, available online: http://www.tandfonline.com/10.1080/17460654.2011.601166.While historians of spiritualism have been eager to focus on its political and social implications, less attention has been given to the fact that spirit communication was also a matter of visual spectacle. This article aims to analyse spiritualist séances as a form of spectacular entertainment. Relying on a wide array of spiritualist sources, it argues that séances were meant not only as moments of religious and scientific inquiry, but also as a brilliant amusement where theatrical effects embellished an exciting shared experience. The intermingling of religion and entertainment can thus be seen as one of the defining characteristics of the spiritualist experience. After sketching the history of the presence of spiritualist mediums on the stage and discussing the involvement of professionalism in mediumship, the article will then focus on the trance as a specific performance strategy. It will examine how the trance combined issues of automatism, theatricality and absorption, and contributed to the coexistence in spirit seances of spectacular features and claims of authenticity

The invisible made visible: X-rays as attraction and visual medium at the end of the nineteenth century

This is an Accepted Manuscript of an article published by Taylor & Francis in Media History on 29th July 2011, available online: http://wwww.tandfonline.com/10.1080/13688804.2011.602856This article focuses on the early history of X-rays. It argues that, during the first years after their discovery in 1895 by German physicist Wilhelm Conrad Röntgen, they were regarded as a technological attraction and a visual medium. While their application in medical practice was not yet fully established, the possibility of seeing into the realm of the invisible encouraged pioneers of this technology to actively exploit their visual powers. By using a media-history framework, and relying on primary and secondary sources in English, German, French, and Italian, the article takes into account three aspects of the rays' early display: its character of technological attraction; its association with photography; and its connection to beliefs in the supernatural and the occult

Photography and communication media in the nineteenth century

This is an Accepted Manuscript of an article published by Taylor & Francis in History of Photography on 12th September 2012, available online: http://wwww.tandfonline.com/10.1080/03087298.2012.680306The increasing interest in media history within the academic world has not yet resulted in an intensive examination of the relationship between photography and communications media. This article seeks to begin to address this lacuna by examining photography's insertion into the so-called revolution of communication in middle-nineteenth-century America. The first section of the present study links photography to the introduction of telegraphy, the development of the railway and the expansion of the postal system. The second section examines aspects of the reception of photography in nineteenth-century America and argues this is related to improvements in communication and transportation technologies. The conclusion calls for a broader consideration of the links between the history of photography and the history of media

The small xx behavior of the gluon structure function from total cross sections

Within a QCD-based eikonal model with a dynamical infrared gluon mass scale we discuss how the small $x$ behavior of the gluon distribution function at moderate $Q^{2}$ is directly related to the rise of total hadronic cross sections. In this model the rise of total cross sections is driven by gluon-gluon semihard scattering processes, where the behavior of the small $x$ gluon distribution function exhibits the power law $xg(x,Q^2)= h(Q^2)x^{-\epsilon}$. Assuming that the $Q^{2}$ scale is proportional to the dynamical gluon mass one, we show that the values of $h(Q^2)$ obtained in this model are compatible with an earlier result based on a specific nonperturbative Pomeron model. We discuss the implications of this picture for the behavior of input valence-like gluon distributions at low resolution scales.Comment: 19 pages, 3 figures; revised version; to appear in Int. J. Mod. Phys.

Development of boron calibration via hybrid comparator method in prompt gamma activation analysis

The prompt gamma activation analysis (PGAA) facility at the Nuclear Engineering Teaching Laboratory at The University of Texas at Austin was utilized to quantify boron concentrations in boron carbide semiconductor films deposited on silicon substrates. Calibration was complicated by the unique and varying sample geometries analyzed. In addition, there was a dearth of solid materials available with quantified boron concentrations having comparable or readily modifiable dimensions to exploit for calibration purposes. Therefore, a novel hybrid comparator method was developed for the quantification of boron utilizing aluminum as an inexpensive and easily machinable reference material. Aluminum samples were manufactured with high tolerances to match the geometry of each sample of interest. Each boron carbide film sample and its congruent aluminum sample were measured in the PGAA system. The measured aluminum responses and relevant nuclear parameters were used to standardize the measurements. A boron standard was created using a procedure derived from a similar approach used by the National Institute of Standards and Technology. Quality control measurements using this standard show that the method provided accuracy to within 5% for boron quantification