Tag Archives: Evento scientifico

I discuss a class of weak-scale extensions of the Standard Model which is completely invisible to low-energy indirect probes. The typical signature of this scenario is the existence of new charged and/or colored states which are stable on the scale of high-energy particle detectors.

The Hagedron’s thermodynamical theory for high energy collisions has been recently extended by including Tsallis statistics. With this extension, a non-additive character was given to the so-called self-consistent thermodynamics leading to a power-law behaviour of the relevant distributions. In this talk a brief review of the extended Hagedorn’s theory will be given, and new results obtained with the nonextensive theory will be shown.

With the LHC experiments gathering more data, the exploration of the symmetry breaking sector of the Standard Model will gain renewed impetus. Likewise, it is important to search for dark matter candidates being a degree of freedom missing in the Standard Model. An invisible axion is an interesting candidate for dark matter. However trying to look for direct evidence of its existence at the LHC is hopeless as it is extremely weakly coupled. Therefore we have to resort to less direct ways to explore this sector by formulating consistent models that include the axion and deriving consequences that could be experimentally tested. In this talk we explored such consequences in the DFS model, an extension of the 2HDM with axion.

The OPERA experiment at the Gran Sasso underground laboratory has been designed to study the νμ→ντ oscillation in appearance mode in the CNGS neutrino beam. The efforts of the Collaboration to extend the analysed data sample, with five identified ντ candidates overall, and to improve the knowledge of the expected background allowed to establish the discovery of νμ→ντ oscillation with a significance larger than 5 σ. In this talk, the ντ data analysis will be discussed, with emphasis on the background constraints obtained by using dedicated data-driven control samples. The analysis of the present τ neutrino and electron neutrino samples in the framework of the 3+1 sterile model will be presented. Finally the analysis of the muon charge ratio in the cosmic ray sample will be covered.

Discrete Z_N symmetries are a common “artifact” of beyond the standard model physics models. They provide different avenues for constructing consistent scenarios for lepton and quark mixing patterns, radiative neutrino mass generation as well as dark matter stabilization. In this talk I will show how these symmetries can be derived from the spontaneous breaking of the Abelian U(1) factors contained in the global flavor symmetry transformations of the gauge invariant kinetic Lagrangian. I will show how this idea can be implemented in scenarios with right-handed neutrinos.

The SuperKEKB project is a positron-electron collider built to explore new phenomena in particle physics. The physics program of the next B- factory delivering ultra high statistics is almost independent of, and/or complementary to, the high energy experiments at the LHC. The target luminosity is 8×10^35 cm^-2s^-1, which is 40 times the performance of the previous KEKB accelerator, which has been operated during 11 years until 2010. The consideration of SuperKEKB began in 2001. The strategy for the luminosity upgrade was a high-current scheme in the early stage. However,difficulties such as a bunch lengthening due to coherent synchrotron radiation and the need for a huge reinforcement of the RF system were encountered. As a result, in 2009 we have changed the strategy from the previous high-current to a novel “nano-beam” scheme. The nano-beam scheme was first proposed by P. Raimondi in Italy. Here the collision of low emittance beams under a large crossing angle allows squeezing the beta function at IP to values much smaller than the bunch length. Consequently, the 40 times higher target luminosity can be achieved with only twice the beam current of KEKB. The commissioning of SuperKEKB will start in early next year. In this seminar the latest upgrade schedule and the recent progress of the accelerator construction will be presented.

The Frascati National Laboratories organize the first edition of a workshop dedicated to the young researchers whose PHD theses have been awarded by INFN scientific committees. It is an opportunity for these young scientists to illustrate their work to their colleagues. All different INFN scientific areas will be covered. 2014 Award “Marcello Conversi” for Lines of Research I 2014 Award “Bruno Rossi” for Lines of Research II 2014 Award “Claudio Villi” for Lines of Research III 2014 Award “Sergio Fubini” for Lines of Research IV 2014 Award “Francesco Resmini” for Lines of Research V  

Abstract. I will report our recent experimental studies on pionic atoms and eta'-mesic nuclei. Pionic atoms are known to provide irreplaceable information on the pion-nucleus interaction. Our recent spectroscopy of pionic atoms in (d,3He) reactions provides very high precision information on the binding energies and widths, and thus we expect more stringent constraints to be set to the pion-nucleus interaction. In the presentation, our recent activities on an experiment for eta' mesic nuclei search at GSI/FAIR will also be discussed in the context of the mass generation mechanism of the mesons.

Cosmic strings are linear gravitational stable topological defects which may have been created as a consequence of phase transitions in the early universe. The formation of cosmic strings can have astrophysical and cosmological consequences. The geometry of the spacetime associated with an idealized cosmic string, i.e. infinitely long and straight, is locally flat except on the string. In quantum field theory, the corresponding nontrivial topology induces non-zero vacuum expectation values (VEVs) for physical observables. In this talk, we analyze the bosonic current densities induced by a magnetic flux running along an idealized cosmic string, admitting that the coordinate along the string’s axis is compactified. Additionally, we admit the presence of a magneti flux enclosed by the compactification axis. In order to develop this analysis, we calculate the complete set of normalized bosonic wave functions obeying a quasiperiodicity condition along the compactified dimension. In this context, only azimuthal and axial currents densities take place.