Complesso Universitario Of Monte Santangelo

Napoli, Italy

Complesso Universitario Of Monte Santangelo

Napoli, Italy
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Ricciardi G.,University of Naples Federico II | Ricciardi G.,Complesso Universitario Of Monte Santangelo
EPJ Web of Conferences | Year: 2017

Flavour physics is currently well described by the Standard Model except for some measurements which could be signalling new physics. We briefly summarize the status of tensions in rare exclusive semi-leptonic B decays and in RK/D(∗) ratios. We also address the issue of the long standing tension in the |Vcb| and |Vub| exclusive/inclusive determinations. © The Authors, published by EDP Sciences, 2017.


Di Donato C.,Complesso Universitario Of Monte Santangelo | Ricciardi G.,Complesso Universitario Of Monte Santangelo | Ricciardi G.,University of Naples Federico II | Bigi I.I.,University of Notre Dame
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

It has been realized for a long time that knowing the η and η ′ wave functions in terms of quark and gluon components probes our understanding of nonperturbative QCD dynamics. Great effort has been given to this challenge, yet no clear picture has emerged even with the most recent KLOE data. We point out which measurements would be most helpful in arriving at a more definite conclusion. A better knowledge of these wave functions will significantly help to disentangle the weight of different decay subprocesses in semileptonic decays of D +, Ds+, and B + mesons. The resulting insights will be instrumental in treating even nonleptonic B transitions involving η and η ′ and their CP asymmetries; thus they can sharpen the case for or against new physics intervening there. © 2012 American Physical Society.


Mirizzi A.,University of Hamburg | Mangano G.,Complesso Universitario Of Monte Santangelo | Pisanti O.,Complesso Universitario Of Monte Santangelo | Pisanti O.,University of Naples Federico II | Saviano N.,Durham University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Secret interactions among sterile neutrinos have been recently proposed as an escape route to reconcile eV sterile neutrino hints from short-baseline anomalies with cosmological observations. In particular models with coupling gX?10-2 and gauge boson mediators X with MX?10MeV lead to large matter potential suppressing the sterile neutrino production before the neutrino decoupling. With this choice of parameter ranges, big-bang nucleosynthesis is left unchanged and gives no bound on the model. However, we show that at lower temperatures when active-sterile oscillations are no longer matter suppressed, sterile neutrinos are still in a collisional regime, due to their secret self-interactions. The interplay between vacuum oscillations and collisions leads to a scattering-induced decoherent production of sterile neutrinos with a fast rate. This process is responsible for a flavor equilibration among the different neutrino species. We explore the effect of this large sterile neutrino population on cosmological observables. We find that a signature of strong secret interactions would be a reduction of the effective number of neutrinos Neff at matter radiation equality down to 2.7. Moreover, for MX?gXMeV sterile neutrinos would be free-streaming before becoming nonrelativistic and they would affect the large-scale structure power spectrum. As a consequence, for this range of parameters we find a tension of an eV mass sterile state with cosmological neutrino mass bounds. © 2015 American Physical Society.


Buccella F.,Complesso Universitario Of Monte Santangelo | Fong C.S.,National Institute of Nuclear Physics, Italy | Nardi E.,National Institute of Nuclear Physics, Italy | Ricciardi G.,Complesso Universitario Of Monte Santangelo | Ricciardi G.,University of Naples Federico II
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We consider the see-saw mechanism within a nonsupersymmetric SO(10) model. By assuming the SO(10) quark-lepton symmetry, and after imposing suitable conditions that ensure that the right-handed neutrino masses are at most mildly hierarchical (compact right-handed spectrum) we obtain a surprisingly predictive scenario. The absolute neutrino mass scale, the Dirac and the two Majorana phases of the neutrino mixing matrix remain determined in terms of the set of already measured low energy observables, modulo a discrete ambiguity in the signs of two neutrino mixing angles and of the Dirac phase. The right-handed neutrino mass spectrum is also predicted, as well as the size and sign of the leptogenesis CP asymmetries. We compute the cosmological baryon asymmetry generated through leptogenesis and obtain the correct sign, and a size compatible with observations. © 2012 American Physical Society.


Rosa L.,University of Naples Federico II | Rosa L.,Complesso Universitario Of Monte Santangelo
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We compute the Casimir energy of a spherical region using a surface impedance approach. We characterize the surface impedance of the boundary using a plasma model. Exact analytical formulas are obtained by means of the zeta function regularization method and all the divergencies are explicitly computed. We find that it is possible to have negative Casimir energy for some range of values of the relevant parameter y a=ω pa√ μ. Limits of applicability of the model are discussed. © 2012 American Physical Society.


Ricciardi G.,University of Naples Federico II | Ricciardi G.,Complesso Universitario Of Monte Santangelo
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We discuss the impact of recent progress in semileptonic D decays on light flavor spectroscopy and estimate mixing parameters in the η- η′ system. © 2012 American Physical Society.


Ricciardi G.,University of Naples Federico II | Ricciardi G.,Complesso Universitario Of Monte Santangelo
Modern Physics Letters A | Year: 2013

We review the current status of |Vcb|, |Vub| and |Vtb|, the absolute values of the matrix elements in the CKM third column. © World Scientific Publishing Company.


Capozziello S.,University of Naples Federico II | Capozziello S.,Complesso Universitario Of Monte Santangelo | Cardone V.F.,National institute for astrophysics | Farajollahi H.,Guilan University | Ravanpak A.,Guilan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

Based only on the assumption that the Universe is homogenous and isotropic on large scales, cosmography is an ideal tool to investigate the cosmic expansion history in an almost model-independent way. Fitting the data on the luminosity distance and baryon acoustic oscillations allows to determine the confidence ranges for the cosmographic parameters hence giving some quantitative constraints that at whatever theory has to fulfill. As an application, we consider here the case of teleparallel gravity also referred to as f(T) gravity. To this end, we first work out analytical expressions to express the present day values of f(T) derivatives as a function of the cosmographic parameters, which hold under quite general and physically motivated conditions. We then use the constraints coming from cosmography to find out the confidence ranges for f(T) derivatives up to the fifth order and show how these can be used to check the viability of given teleparallel gravity models without the need to explicitly solve the second order dynamic equations. © 2011 American Physical Society.


Ibort A.,Charles III University of Madrid | Perez-Pardo J.M.,Complesso Universitario Of Monte Santangelo
International Journal of Geometric Methods in Modern Physics | Year: 2015

This is a series of five lectures around the common subject of the construction of self-adjoint extensions of symmetric operators and its applications to Quantum Physics. We will try to offer a brief account of some recent ideas in the theory of self-adjoint extensions of symmetric operators on Hilbert spaces and their applications to a few specific problems in Quantum Mechanics. © 2015 World Scientific Publishing Company.


Mollo C.M.,Complesso Universitario Of Monte Santangelo
EPJ Web of Conferences | Year: 2016

Since almost a century photomultipliers have been the main sensors for photon detection in nuclear and astro-particle physics experiments. In recent years the search for cosmic neutrinos gave birth to enormous size experiments (Antares, Kamiokande, Super-Kamiokande, etc.) and even kilometric scale experiments as ICECUBE and the future KM3NeT. A very large volume neutrino telescope like KM3NeT requires several hundreds of thousands photomultipliers. The performance of the telescope strictly depends on the performance of each PMT. For this reason, it is mandatory to measure the characteristics of each single sensor. The characterization of a PMT normally requires more than 8 hours mostly due to the darkening step. This means that it is not feasible to measure the parameters of each PMT of a neutrino telescope without a system able to test more than one PMT simultaneously. For this application, we have designed, developed and realized a system able to measure the main characteristics of 62 3-inch photomultipliers simultaneously. Two measurement sessions per day are possible. In this work, we describe the design constraints and how they have been satisfied. Finally, we show the performance of the system and the first results coming from the test of few thousand tested PMTs. © Owned by the authors, published by EDP Sciences, 2016.

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