Astrophysical neutrino production and impact of associated uncertainties in photo-hadronic interactions of UHECRs

High energy neutrinos can be produced by interactions of ultra-high energy cosmic rays (UHECRs) in the dense radiation fields of their sources as well as off the cosmic backgrounds when they propagate through the universe. Multi-messenger interpretations of current measurements deeply rely on the understanding of these interactions. In order to efficiently produce neutrinos in the sources of UHECRs, at least a moderate level of interactions is needed, which means that a nuclear cascade develops if nuclei are involved. On the other hand, the available cross-section data and interaction models turn out to make poor predictions for most nuclei heavier than protons. We show the impact of these uncertainties in state-of-the-art photo-disintegration models and motivate nuclear cross-section measurements. Further, we discuss extensions for photo-meson models currently used in astrophysics and demonstrate the importance of understanding the details of UHECR interaction with the Glashow resonance.Comment: invited talk presented at ISVHECRI 2018, submitted for publication to EPJ Web of Conference

Thick braneworlds generated by a non-minimally coupled scalar field and a Gauss-Bonnet term: conditions for localization of gravity

We consider warped five-dimensional thick braneworlds with four-dimensional Poincar\'e invariance originated from bulk scalar matter non-minimally coupled to gravity plus a Gauss-Bonnet term. The background field equations as well as the perturbed equations are investigated. A relationship between 4D and 5D Planck masses is studied in general terms. By imposing finiteness of the 4D Planck mass and regularity of the geometry, the localization properties of the tensor modes of the perturbed geometry are analyzed to first order, for a wide class of solutions. In order to explore the gravity localization properties for this model, the normalizability condition for the lowest level of the tensor fluctuations is analyzed. It is found that for the examined class of solutions, gravity in 4 dimensions is recovered if the curvature invariants are regular and the 4D Planck mass is finite. It turns out that both the addition of the Gauss-Bonnet term and the non-minimal coupling between the scalar field and gravity {\it reduce} the value of the 4D Planck mass compared to its value when the scalar field and gravity are minimally coupled and the Gauss-Bonnet term is absent. The above discussed analysis depends on the explicit form of the scalar field (through its non-minimal coupling to gravity), making necessary the construction of explicit solutions in order to get results in closed form, and is illustrated with some examples which constitute smooth generalizations of the so-called Randall-Sundrum braneworld model. These solutions were obtained by making use of a detailed {\it singular perturbation theory} procedure with respect to the non-minimal coupling parameter between the scalar field and gravity, a difficult task that we managed to perform in such a way that all the physically meaningful conditions for the localization of gravity are fully satisfied. From the obtained...Comment: 27 pages, uses iopart, 12 figure

An anisotropic standing wave braneworld and associated Sturm-Liouville problem

We present a consistent derivation of the recently proposed 5D anisotropic standing wave braneworld generated by gravity coupled to a phantom-like scalar field. We explicitly solve the corresponding junction conditions, a fact that enables us to give a physical interpretation to the anisotropic energy-momentum tensor components on the brane. So matter on the brane represents an oscillating fluid which emits anisotropic waves into the bulk. We also analyze the Sturm-Liouville problem associated to the correct localization condition of the transverse to the brane metric and scalar fields. It is shown that this condition restricts the physically meaningful space of solutions for the localization of the fluctuations of the model.Comment: 17 pages, uses iopart, presented at GR19, Mexico City, Mexico, 5-9 July 201

A de Sitter tachyon thick braneworld

Among the multiple 5D thick braneworld models that have been proposed in the last years, in order to address several open problems in modern physics, there is a specific one involving a tachyonic bulk scalar field. Delving into this framework, a thick braneworld with a cosmological background induced on the brane is here investigated. The respective field equations --- derived from the model with a warped 5D geometry --- are highly non-linear equations, admitting a non-trivial solution for the warp factor and the tachyon scalar field as well, in a de Sitter 4D cosmological background. Moreover, the non-linear tachyonic scalar field, that generates the brane in complicity with warped gravity, has the form of a kink-like configuration. Notwithstanding, the non-linear field equations restricting character does not allow one to easily find thick brane solutions with a decaying warp factor which leads to the localization of 4D gravity and other matter fields. We derive such a thick brane configuration altogether in this tachyon-gravity setup. When analyzing the spectrum of gravity fluctuations in the transverse traceless sector, the 4D gravity is shown to be localized due to the presence of a {\it single} zero mode bound state, separated by a continuum of massive Kaluza-Klein (KK) modes by a mass gap. It contrasts with previous results, where there is a KK massive bound excitation providing no clear physical interpretation. The mass gap is determined by the scale of the metric parameter $H$. Finally, the corrections to Newton's law in this model are computed and shown to decay exponentially. It is in full compliance to corrections reported in previous results (up to a constant factor) within similar braneworlds with induced 4D de Sitter metric, despite the fact that the warp factor and the massive modes have a different form.Comment: 16 pages in latex, 4 figures, JCAP format, title changed, presentation improved, figures added, discussion on stability include

Ocio deportivo en los waterfronts de Bilbao y Barcelona : un estudio comparativo

Este estudio busca conocer el papel del ocio deportivo en la construcción social del espacio público regenerado en frentes de costa o riberas urbanas de Bilbao y Barcelona. Para ello, se realiza, en primer lugar, un análisis de los usos deportivos que acogen los waterfronts y los procesos de apropiación del espacio que subyacen a dichos usos. A continuación, se explora el perfil de las y los practicantes deportivos, usuarios de los waterfronts para reflexionar sobre la contribución del ocio deportivo en estos espacios al derecho a la ciudad. El estudio se apoya en una metodología mixta que combina la observación no participada y una breve encuesta administrada en los waterfronts de sendas ciudades. Los resultados confirman que existe una relación de bidireccionalidad entre espacios públicos urbanos regenerados y estilos de ocio de la ciudadanía. Si bien es cierto que los waterfronts actúan como tractores de las prácticas deportivas, también es verdad que dichas prácticas contribuyen a la transformación social del entorno urbano, mediante procesos de apropiación que resignifican su valor y participan en el desarrollo social de las ciudades.This study seeks to understand the role of sport leisure in the social construction of regenerated public spaces on coast fronts or urban riverbanks of Bilbao and Barcelona. To do this, first it performed an analysis of sports uses hosted in the waterfronts and the processes of place appropriation that underlie such uses. Then, a profile scan is performed on people doing sport (waterfront users), in order to consider the contribution of sport leisure in these spaces to "the right to the city". The study is based on a mixed methodology combining non-participatory observation and a brief survey administered in the waterfronts of both cities. The results confirm that there is a bidirectional relationship between regenerated urban public spaces and leisure styles of citizens. While it is true that the waterfronts act as tractors of sports practices, it is also true that these practices contribute to the social transformation of the urban environment through processes of appropriation that give a new meaning to its value and promote the exchange of experiences that contribute to the social development of cities

Study of field fluctuations and their localization in a thick braneworld generated by gravity non-minimally coupled to a scalar field with the Gauss-Bonnet term

In this work we study a scenario with a warped 5D smooth braneworld with 4D Minkowski geometry builded from bulk scalar matter non-minimally coupled to gravity with an additional Gauss-Bonnet term. We present exact solutions for the full braneworld configuration in contrast to previous results where only approximate solutions were constructed due to the highly non-linear character of the relevant differential equations. These solutions allow us to study the necessary conditions for the finiteness of the 4D Planck mass and additionally, enables us to perform a more rigorous analysis of 4D gravity localization compared to approximate approaches. It is remarkable that all the constructed braneworld configurations lead to standard 4D gravity localization since they contain a localized massless tensor mode (the graviton). We also analyze the localization properties of scalar, vector and tensor fluctuation modes for the constructed field configurations. We show that for the considered backgrounds, only the massless tensor mode, i.e. the 4D graviton, is localized on the brane, while the vector and scalar modes are not confined to the brane.Comment: 24 pages in latex, 5 figure