A Geometric Picture For Fermion Masses

We describe a geometric picture for the pattern of fermion masses of the three generations which is invariant with respect to the renormalization group below the electroweak scale. Moreover, we predict the upper limit for the ratio between the Dirac masses of the $\mu$ and $\tau$ neutrinos, $m_{\nu_{\mu}}/ m_{\nu_{\tau}} < (9.6 \pm 0.6) 10^{-3}$.Comment: 7 pages LATEX + 1 figur

Qualitative properties of the Dirac equation in a central potential

The Dirac equation for a massive spin-1/2 field in a central potential V in three dimensions is studied without fixing a priori the functional form of V . The second-order equations for the radial parts of the spinor wavefunction are shown to involve a squared Dirac operator for the free case, whose essential self-adjointness is proved by using the Weyl limit point-limit circle criterion, and a ‘perturbation’ resulting from the potential. One then finds that a potential of Coulomb type in the Dirac equation leads to a potential term in the above second-order equations which is not even infinitesimally form-bounded with respect to the free operator. Moreover, the conditions ensuring essential self-adjointness of the second-order operators in the interacting case are changed with respect to the free case, i.e. they are expressed by a majorization involving the parameter in the Coulomb potential and the angular momentum quantum number. The same methods are applied to the analysis of coupled eigenvalue equations when the anomalous magnetic moment of the electron is not neglected

Numerov and phase-integral methods for charmonium

This paper applies the Numerov and phase-integral methods to the stationary Schrödinger equation that studies bound states of charm anti-charm quarks. The former is a numerical method well suited for a matrix form of the second-order ordinary differential equations, and can be applied whenever the stationary states admit a Taylor-series expansion. The latter is an analytic method that provides, in principle, even exact solutions of the stationary Schrödinger equation, and well suited for applying matched asymptotic expansions and higher-order quantization conditions. The Numerov method is found to be always in agreement with the early results of Eichten et al., whereas an original evaluation of the phase-integral quantization condition clarifies under which conditions the previous results in the literature on higher-order terms can be obtained

Numerov and phase-integral methods for charmonium

This paper applies the Numerov and phase-integral methods to the stationary Schrodinger equation that studies bound states of charm anti-charm quarks. The former is a numerical method well suited for a matrix form of second-order ordinary di erential equations, and can be applied whenever the stationary states admit a Taylor-series expansion. The latter is an analytic method that provides, in principle, even exact solutions of the stationary Schrodinger equation, and well suited for applying matched asymptotic expansions and higher order quantization conditions. The Numerov method is found to be always in agreement with the early results of Eichten et al., whereas an original evaluation of the phase-integral quantization condition clarifies under which conditions the previous results in the literature on higher-order terms can be obtained.Comment: 23 pages, 2 tables and 2 figure

On the phase-integral method for the radial Dirac equation

In the application of potential models, the use of the Dirac equation in central potentials remains of phenomenological interest. The associated set of decoupled second-order ordinary differential equations is here studied by exploiting the phase-integral technique, following the work of Froman and Froman that provides a powerful tool in ordinary quantum mechanics. For various choices of the scalar and vector parts of the potential, the phase-integral formulae are derived and discussed, jointly with formulae for the evaluation of Stokes and anti-Stokes lines. A criterion for choosing the base function in the phase-integral method is also obtained, and tested numerically. The case of scalar confinement is then found to be more tractable.Comment: 19 pages, 8 figures. In the new version, the presentation has been improved. A new figure and new references have been adde

Quantum Effects in Friedmann-Robertson-Walker Cosmologies

Electrodynamics for self-interacting scalar fields in spatially flat Friedmann-Robertson-Walker space-times is studied. The corresponding one-loop field equation for the expectation value of the complex scalar field in the conformal vacuum is derived. For exponentially expanding universes, the equations for the Bogoliubov coefficients describing the coupling of the scalar field to gravity are solved numerically. They yield a non-local correction to the Coleman-Weinberg effective potential which does not modify the pattern of minima found in static de Sitter space. Such a correction contains a dissipative term which, accounting for the decay of the classical configuration in scalar field quanta, may be relevant for the reheating stage. The physical meaning of the non-local term in the semiclassical field equation is investigated by evaluating this contribution for various background field configurations.Comment: 17 pages, plain TeX + 5 uuencoded figure

The effects of the COVID-19 pandemic on the training of athletes with disabilities in the 7-a-side football championship

This study had as its main objective to investigate the difference in training programs carried out in athletes with disabilities practicing 7-a-side football before and after the Covid-19 pandemic. The two sporting seasons taken into consideration concerned the 2018/19 season and the 2020/2021 season. The study was conducted on ten disabled athletes belonging to a football school in Campania, Italy. The comparison between the two sports seasons is given in numerical terms by the statistical comparison of the results of the adapted motor tests concerning aerobic capacity and conditional capacities, which were administered to the athletes at the beginning and at the end of both sports seasons. From this comparison, in both seasons, minor improvements in the 2020/2021 season were found in athletes, between the entry and exit tests. It can be said that the consequences of the Covid-19 pandemic, concerning social distancing and the interruption of sports activities, have played a primary role in the decline in the improvement of athletes with disabilities for 7-a-side football in the 2020/2021 sports season

The Role of 3PL Internet Technology in Supporting Extended Enterprise Integration: an Exploratory Survey

Information and Communications Technology (ICT) is widely regarded as a key integration enabler in contemporary supply chain configurations. Additionally, as increasing numbers of manufacturers and retailers outsource significant parts of their supply chain functionality, the world has seen the vertical disintegration of supply chains. As a result of these and other developments, the extended enterprise (EE) business model has become more widely adopted in a range of sectors. In this environment, third party logistics (3PL) providers (the majority of which are small companies) may play a pivotal role in integrating physical and information flows in new business models through the use of ICT, namely through Internet websites. This paper presents the results of an exploratory, empirical investigation conducted on the website content of a sample of 153 small Italian logistics service companies. The results of the survey show managerial implications for small 3PL companies and indicates possible future research directions in this field. This is especially important considering the paucity of research in the field of small 3PLs and little empirical investigation into the use of websites by such firms

Supply Chain Innovation for Competing in Highly Dynamic Markets: Challenges and Solutions: Preface

This book investigates the role of innovation in the management of supply chains of today, focusing on supply chain integration from both strategic and operational perspectives and the impact of information-related innovation in supply chain and logistics service industries

Preface

The purpose of this chapter is to identify the necessary components of intelligent Freight Transportation System (IFTS) and analyze the potential effects on transport operations performances in all the three pillars of sustainability, namely the economics, environmental and social impacts. In order to achievethis objective, a literature study was conducted, looking for relevant up-to-date literature within the fields of transportation, logistics, and information and communication technology (ICT) and environmental impacts of freight transportation. In addition, two separate rounds of empirical studies weremade. From literature, as well as from part of the empirical data collection, a requirement analysis was done to understand issues and problems in transport operations that can be addressed with more sophisticated information and communication systems. The second round of empirical data collection wasdone to identify potential solutions of the identified issues. Finally an analysis was made to understand the functionalities of possible IFTS solutions. Many effects were found that can contribute to increased performance of transport operations including automatic item identification, safety and security prevention, real-time navigation, traffic situation notification and carbon footprint registration