TeV gravity at neutrino telescopes

Cosmogenic neutrinos reach the Earth with energies around 10^9 GeV, and their interactions with matter will be measured in upcoming experiments (Auger, IceCube). Models with extra dimensions and the fundamental scale at the TeV could imply signals in these experiments. In particular, the production of microscopic black holes by cosmogenic neutrinos has been extensively studied in the literature. Here we make a complete analysis of gravity-mediated interactions at larger distances, where they can be calculated in the eikonal approximation. In these processes a neutrino of energy E_\nu interacts elastically with a parton inside a nucleon, loses a small fraction y of its energy, and starts a hadronic shower of energy y E_\nu << E_\nu. We analyze the ultraviolet dependence and the relevance of graviton emission in these processes, and show that they are negligible. We also study the energy distribution of cosmogenic events in AMANDA and IceCube and the possibility of multiple-bang events. For any neutrino flux, the observation of an enhanced rate of neutral current events above 100 TeV in neutrino telescopes could be explained by TeV-gravity interactions. The values of the fundamental scale of gravity that IceCube could reach are comparable to those to be explored at the LHC.Comment: 10 pages, 7 figures; new section on air showers added, version to be publishe

GUT and flavor models for neutrino masses and mixing

In the recent years neutrino experiments have studied in detail the phenomenon of neutrino oscillations and most of the oscillation parameters have been measured with a good accuracy. However, in spite of many interesting ideas, the problem of flavor in the lepton sector remains an open issue. In this review, we discuss the state of the art of models for neutrino masses and mixings formulated in the context of flavor symmetries, with particular emphasis on the role played by grand unified gauge groups.Comment: Added new reference

Constraining new physics scenarios in neutrino oscillations from Daya Bay data

We perform for the first time a detailed fit to the $\bar \nu_e \to \bar \nu_e$ disappearance data of the Daya Bay experiment to constrain the parameter space of models where sterile neutrinos can propagate in a large compactified extra dimension (LED) and models where non-standard interactions affect the neutrino production and detection (NSI). We find that the compactification radius $R$ in LED scenarios can be constrained at the level of $0.57 \, \mu m$ for normal ordering and of $0.19\, \mu m$ for inverted ordering, at 2$\sigma$ confidence level. For the NSI model, reactor data put a strong upper bound on the parameter $\varepsilon_{ee}$ at the level of $\sim 10^{-3}$, whereas the main effect of $\varepsilon_{e\mu}$ and $\varepsilon_{e\tau}$ is a worsening of the determination of $\theta_{13}$.Comment: 5 pages, 2 figure

Metamodel variability analysis combining bootstrapping and validation techniques

Research on metamodel-based optimization has received considerably increasing interest in recent years, and has found successful applications in solving computationally expensive problems. The joint use of computer simulation experiments and metamodels introduces a source of uncertainty that we refer to as metamodel variability. To analyze and quantify this variability, we apply bootstrapping to residuals derived as prediction errors computed from cross-validation. The proposed method can be used with different types of metamodels, especially when limited knowledge on parameters’ distribution is available or when a limited computational budget is allowed. Our preliminary experiments based on the robust version of the EOQ model show encouraging results

Interference Calculation in Asynchronous Random Access Protocols using Diversity

The use of Aloha-based Random Access protocols is interesting when channel sensing is either not possible or not convenient and the traffic from terminals is unpredictable and sporadic. In this paper an analytic model for packet interference calculation in asynchronous Random Access protocols using diversity is presented. The aim is to provide a tool that avoids time-consuming simulations to evaluate packet loss and throughput in case decodability is still possible when a certain interference threshold is not exceeded. Moreover the same model represents the groundbase for further studies in which iterative Interference Cancellation is applied to received frames.Comment: This paper has been accepted for publication in the Springer's Telecommunication Systems journal. The final publication will be made available at Springer. Please refer to that version when citing this paper; Springer Telecommunication Systems, 201

Probability Densities of the effective neutrino masses mβm_{\beta } and mββm_{\beta \beta}

We compute the probability densities of the effective neutrino masses $m_{\beta }$ and $m_{\beta \beta}$ using the Kernel Density Estimate (KDE) approach applied to a distribution of points in the $(m_{\min}, m_{\beta\beta })$ and $(m_{\beta }, m_{\beta\beta })$ planes, obtained using the available Probability Distribution Functions (PDFs) of the neutrino mixing and mass differences, with the additional constraints coming from cosmological data on the sum of the neutrino masses. We show that the reconstructed probability densities strongly depend on the assumed set of cosmological data: for $\sum_j m_j \leq 0.68\ @\ 95\% \ \mathrm{CL}$ a sensitive portion of the allowed values are already excluded by null results of experiments searching for $m_{\beta \beta}$ and $m_{\beta }$, whereas in the case $\sum_j m_j \leq 0.23\ @\ 95\% \ \mathrm{CL}$ the bulk of the probability densities are below the current bounds.Comment: 12 pages, 6 figures, 4 tables. Improved discussion and references added, typos corrected, matches published version in NP