Aspects of symmetry breaking in SO(10) GUTs

I review some recent results on the Higgs sector of minimal SO(10) grand unified theories both with and without supersymmetry. It is shown that nonsupersymmetric SO(10) with just one adjoint triggering the first stage of the symmetry breaking does provide a successful gauge unification when radiative corrections are taken into account in the scalar potential, while in the supersymmetric case it is argued that the troubles in achieving a phenomenologically viable breaking with representations up to the adjoint are overcome by considering the flipped SO(10) embedding of the hypercharge.Comment: 8 pages, 1 figure; prepared for the proceedings of DISCRETE'10 - Symposium on Prospects in the Physics of Discrete Symmetrie

Time delay of light signals in an energy-dependent spacetime metric

In this note we review the problem of time delay of photons propagating in a spacetime with a metric that explicitly depends on the energy of the particles (Gravity-Rainbow approach). We show that corrections due to this approach -- which is closely related to DSR proposal -- produce for small redshifts ($z<<1$) smaller time delays than in the generic Lorentz Invariance Violating case.Comment: 5 pages. This version contains two new references with respect to the published versio

On the vacuum of the minimal nonsupersymmetric SO(10) unification

We study a class of nonsupersymmetric SO(10) grand unified scenarios where the first stage of the symmetry breaking is driven by the vacuum expectation values of the 45-dimensional adjoint representation. Three decade old results claim that such a Higgs setting may lead exclusively to the flipped SU(5) x U(1) intermediate stage. We show that this conclusion is actually an artifact of the tree level potential. The study of the accidental global symmetries emerging in various limits of the scalar potential offers a simple understanding of the tree level result and a rationale for the drastic impact of quantum corrections. We scrutinize in detail the simplest and paradigmatic case of the 45_{H} + 16_{H} Higgs sector triggering the breaking of SO(10) to the standard electroweak model. We show that the minimization of the one-loop effective potential allows for intermediate SU(4)_C x SU(2)_L x U(1)_R and SU(3)_c x SU(2)_L x SU(2)_R x U(1)_{B-L} symmetric stages as well. These are the options favoured by gauge unification. Our results, that apply whenever the SO(10) breaking is triggered by , open the path for hunting the simplest realistic scenario of nonsupersymmetric SO(10) grand unification.Comment: 22 pages, 1 figure. Refs added. To appear in Phys. Rev.

Tidal gravity observations at Mt. Etna and Stromboli: results concerning the modeled and observed tidal factors

Continuous gravity observations performed in the last few years, both at Mt. Etna and Stromboli, have prompted the need to improve the tidal analysis in order to acquire the best corrected data for the detection of volcano related signals. On Mt. Etna, the sites are very close to each other and the expected tidal factor differences are negligible. It is thus useful to unify the tidal analysis results of the different data sets in a unique tidal model. This tidal model, which can be independently confirmed by a modeling of the tidal parameters based on the elastic response of the Earth to tidal forces and the computation of the ocean tides effects on gravity, is very useful for the precise tidal gravity prediction required by absolute or relative discrete gravity measurements. The change in time of the gravimeters’ sensitivity is also an important issue to be checked since it affects not only the results of tidal analysis but also the accuracy of the observed gravity changes. Conversely, if a good tidal model is available, the sensitivity variations can be accurately reconstructed so as to retune observed tidal records with the synthetic tide, since the tidal parameters are assumed to be constant at a given location

Modified Special Relativity on a fluctuating spacetime

It was recently proposed that deformations of the relativistic symmetry, as those considered in Deformed Special Relativity (DSR), can be seen as the outcome of a measurement theory in the presence of non-negligible (albeit small) quantum gravitational fluctuations [1,2]. In this paper we explicitly consider the case of a spacetime described by a flat metric endowed with stochastic fluctuations and, for a free particle, we show that DSR-like nonlinear relations between the spaces of the measured and classical momenta, can result from the average of the stochastic fluctuations over a scale set be the de Broglie wavelength of the particle. As illustrative examples we consider explicitly the averaging procedure for some simple stochastic processes and discuss the physical implications of our results.Comment: 7 pages, no figure

Deformed Special Relativity as an effective theory of measurements on quantum gravitational backgrounds

In this article we elaborate on a recently proposed interpretation of DSR as an effective measurement theory in the presence of non-negligible (albeit small) quantum gravitational fluctuations. We provide several heuristic arguments to explain how such a new theory can emerge and discuss the possible observational consequences of this framework.Comment: 11 pages, no figure

The application of a denoising method aimed at reducing continuous gravity data

This study summarizes the results obtained by using a processing method based on wavelet transform for noise-filtering of continuous gravity data. Continuous gravity recordings in vol- canic area could play a fundamental role in the monitoring of active volcanoes and in the prediction of eruptive events too. This geophysical methodology is used, on active volcanoes, in order to detect mass changes linked to magma transfer processes and, thus, to recognize forerunners to paroxysmal volcanic events. Spring gravimeters are still the most utilized in- struments for this type of microgravity studies. Unfortunately, spring gravity meters show a strong influence of meteorological parameters, especially in the adverse environmental condi- tions usually encountered at such places. As the gravity changes due to the volcanic activity are very small compared to other geophysical or instrumental effects, we need a new mathematical tool to get reliable gravity residuals susceptible to reflect the volcanic effect. The aim of the present work is to get a first evaluation about the comparison between the traditional filtering methodology and the wavelet transform. The overall results show that the performance of the wavelet-based filter seems better than the Fourier one. Moreover, the possibility of getting a multi-resolution analysis and study local features of the signal in the time domain makes the proposed methodology a valuable tool for gravity data processing

Combined effects of electromagnetic fields on immune and nervous responses.

In technologically developed countries, there is concern about hazards from electromagnetic fields (EMFs). Several studies have reported that immune and neuroendocrine systems exert an integrated response to EMF exposure. The aim of this review is to summarize the results of studies on the effect of low and high frequency EMF on immune and neuroendocrine systems on which our research group has been working for several years

Conventional Fast Neutron Flux Measurement in the Radial Piercing Channel D of the TRIGA Mark II Reactor, Pavia

open8openMarco Di Luzio; Giancarlo D’Agostino; Setareh Fatemi; Barbara Smilgys; Andrea Salvini; Massimo Oddone; Saverio Altieri; Michele PrataDI LUZIO, Marco; D'Agostino, Giancarlo; Fatemi, Setareh; Smilgys, Barbara; Salvini, Andrea; Oddone, Massimo; Altieri, Saverio; Prata, Michel