Hadronic and radiative three-body decays of J/psi involving the scalars f0(1370), f0(1500) and f0(1710)

We study the role of the scalar resonances f0(1370), f0(1500) and f0(1710) in the strong and radiative three-body decays of J/psi with J/psi to V + P P (gamma gamma) and J/psi to gamma + P P (V V), where P (V) denotes a pseudoscalar (vector) meson. We assume that the scalars result from a glueball-quarkonium mixing scheme while the dynamics of the transition process is described in an effective chiral Lagrangian approach. Present data on J/psi to V + P P are well reproduced, predictions for the radiative processes serve as further tests of this scenario.Comment: 15 page

PREDICTION OF ANKLE JOINT TORQUES USING ARTIFICIAL NEURAL NETWORKS

Major ankle sprains in sports are thought to be due to high levels of ankle torsion. The purpose of this study was to develop a method for measuring in vivo ankle torques developed by athletes. Motion capture, force plate, and insole pressure measurements were used to develop generalized regression neural networks to predict maximum ankle torque and rate of ankle torque based on insole pressures. It was found that network prediction accuracy depended on the number of subjects used for training, as well as the method of pressure sensor grouping. Further work will be performed to determine optimal subject and pressure sensor groupings

Escher: Arte e Matemática desenhadas por alunos portugueses

Parte substancial da obra de Escher é dedicada ao estudo do Plano Euclidiano, nomeadamente numa perspetiva de o pavimentar. É sobre este tópico da obra de Escher que incide o presente trabalho o qual pode ser encardao como um ‘tributo’ a Escher e à sua arte. À semelhança de muitos outros já existentes na literatura, este trabalho retrata a harmonia e afinidade existente entre a Arte e a Matemática nas criações do artista. Porém, face a algumas particularidades, julgamos que o nosso estudo prima por alguma singularidade, sendo exemplo elucidativo da expressão gráfica nas Artes Visuais e na Matemática, associado ao relato de uma experiência vivida em contexo escolar. Sustentando-se numa análise e apresentação cuidada dos procedimentos seguidos por Escher para pavimentar o plano, um grupo de alunos em risco de abandono escolar (com idades compreendidas entre os 16 e os 19 anos que não tinham concluído o ensino básico), (re)criou a obra de Escher em painéis de azulejo, mediante produções artísticas originais

Da Arte à Matemática… da Matemática à Arte: uma experiência no Ensino Português

The struggling on identifying strategies and factors that could help to improve the teaching/learning process, regarding the existence of multiple realities, is a subject much discussed in literature. Finding new ways of answer challenges which we came across, is the main reason why this study has been made. The primary goal is centred in applying a Geometry curriculum including many different learning situations based in vocational training. The students were between 16 and 19 years old. Making use of Art is analysed as a potential method to improve Mathematics teaching. Being Escher’s work an element of undiscussable richness with highlights to “Exploration Tessellations”, an investigation has been made to show how some Escher’s works could be a starting point to the introduction of mathematical concepts/contents. It was noticed in a further case that using Art could lead not just to the student’s effective cooperation in the teaching/learning process, as could be a very strong acquisition and way to apply new solid mathematical concepts

Study of the f2(1270)f_2(1270), f2′(1525)f_2'(1525), f0(1370)f_0(1370) and f0(1710)f_0(1710) in the J/ψJ/\psi radiative decays

In this paper we present an approach to study the radiative decay modes of the $J/\psi$ into a photon and one of the tensor mesons $f_2(1270)$, $f'_2(1525)$, as well as the scalar ones $f_0(1370)$ and $f_0(1710)$. Especially we compare predictions that emerge from a scheme where the states appear dynamically in the solution of vector meson--vector meson scattering amplitudes to those from a (admittedly naive) quark model. We provide evidence that it might be possible to distinguish amongst the two scenarios, once improved data are available.Comment: The large Nc argument improved; version published in EPJA

Search for Point Sources of High Energy Neutrinos with AMANDA

This paper describes the search for astronomical sources of high-energy neutrinos using the AMANDA-B10 detector, an array of 302 photomultiplier tubes, used for the detection of Cherenkov light from upward traveling neutrino-induced muons, buried deep in ice at the South Pole. The absolute pointing accuracy and angular resolution were studied by using coincident events between the AMANDA detector and two independent telescopes on the surface, the GASP air Cherenkov telescope and the SPASE extensive air shower array. Using data collected from April to October of 1997 (130.1 days of livetime), a general survey of the northern hemisphere revealed no statistically significant excess of events from any direction. The sensitivity for a flux of muon neutrinos is based on the effective detection area for through-going muons. Averaged over the Northern sky, the effective detection area exceeds 10,000 m^2 for E_{mu} ~ 10 TeV. Neutrinos generated in the atmosphere by cosmic ray interactions were used to verify the predicted performance of the detector. For a source with a differential energy spectrum proportional to E_{nu}^{-2} and declination larger than +40 degrees, we obtain E^2(dN_{nu}/dE) <= 10^{-6}GeVcm^{-2}s^{-1} for an energy threshold of 10 GeV.Comment: 46 pages, 22 figures, 4 tables, submitted to Ap.

Study of the reaction pbar p -> phi phi from 1.1 to 2.0 GeV/c

A study has been performed of the reaction pbar p -> 4K using in-flight antiprotons from 1.1 to 2.0 GeV/c incident momentum interacting with a hydrogen jet target. The reaction is dominated by the production of a pair of phi mesons. The pbar p -> phi phi cross section rises sharply above threshold and then falls continuously as a function of increasing antiproton momentum. The overall magnitude of the cross section exceeds expectations from a simple application of the OZI rule by two orders of magnitude. In a fine scan around the xi/f_J(2230) resonance, no structure is observed. A limit is set for the double branching ratio B(xi -> pbar p) * B(xi -> phi phi) < 6e-5 for a spin 2 resonance of M = 2.235 GeV and Width = 15 MeV.Comment: 13 pages, 13 figures, 2 tables, Latex. To be published in Phys. Rev.