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Search Results: 1 - 10 of 5459 matches for " Luca Panizzi "
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LHC Signatures of Vector-Like Quarks
Yasuhiro Okada,Luca Panizzi
Advances in High Energy Physics , 2013, DOI: 10.1155/2013/364936
Superluminal neutrinos in long baseline experiments and SN1987a
Giacomo Cacciapaglia,Aldo Deandrea,Luca Panizzi
Physics , 2011, DOI: 10.1007/JHEP11(2011)137
Abstract: Precise tests of Lorentz invariance in neutrinos can be performed using long baseline experiments such as MINOS and OPERA or neutrinos from astrophysical sources. The MINOS collaboration reported a measurement of the muonic neutrino velocities that hints to super-luminal propagation, very recently confirmed at 6 sigma by OPERA. We consider a general parametrisation which goes beyond the usual linear or quadratic violation considered in quantum-gravitational models. We also propose a toy model showing why Lorentz violation can be specific to the neutrino sector and give rise to a generic energy behaviour E^alpha, where alpha is not necessarily an integer number. Supernova bounds and the preferred MINOS and OPERA regions show a tension, due to the absence of shape distortion in the neutrino bunch in the far detector of MINOS. The energy independence of the effect has also been pointed out by the OPERA results.
LHC Missing-Transverse-Energy Constraints on Models with Universal Extra Dimensions
Cacciapaglia, Giacomo;Deandrea, Aldo;Ellis, John;Marrouche, Jad;Panizzi, Luca
High Energy Physics - Phenomenology , 2013, DOI: 10.1103/PhysRevD.87.075006
Abstract: We consider the performance of the ATLAS and CMS searches for events with missing transverse energy, which were originally motivated by supersymmetry, in constraining extensions of the Standard Model based on extra dimensions, in which the mass differences between recurrences at the same level are generically smaller than the mass hierarchies in typical supersymmetric models. We consider first a toy model with pair-production of a single vector-like quark U1 decaying into a spin-zero stable particle A1 and jet, exploring the sensitivity of the CMS alphaT and ATLAS meff analysis to U1 mass and the U1-A1 mass difference. For this purpose we use versions of the Delphes generic detector simulation with CMS and ATLAS cards, which have been shown to reproduce the published results of CMS and ATLAS searches for supersymmetry. We then explore the sensitivity of these searches to a specific model with two universal extra dimensions, whose signal is dominated by the pair production of quark recurrences, including searches with leptons. We find that the LHC searches have greater sensitivity to this more realistic model, due partly to the contributions of signatures with leptons, and partly to events with large missing transverse energy generated by the decays of higher-level Kaluza-Klein recurrences. We find that the CMS alphaT analysis with ~5/fb of data at 7 TeV excludes a recurrence scale of 600 GeV at a confidence level above 99%, increasing to 99.9% when combined with the CMS single-lepton search, whereas a recurrence scale of 700 GeV is disfavoured at the 72% confidence level.
Probing the Origin of Neutrino Masses and Mixings via Doubly Charged Scalars: Complementarity of the Intensity and the Energy Frontiers
Tanja Geib,Stephen F. King,Alexander Merle,Jose Miguel No,Luca Panizzi
Physics , 2015,
Abstract: We discuss how the intensity and the energy frontiers provide complementary constraints within a minimal model of neutrino mass involving just one new field beyond the Standard Model at accessible energy, namely a doubly charged scalar $S^{++}$ and its antiparticle $S^{--}$. In particular we focus on the complementarity between high-energy LHC searches and low-energy probes such as lepton flavor violation. Our setting is a prime example of how high- and low-energy physics can cross-fertilize each other.
Higgsphobic and fermiophobic Z' as a single dark matter candidate
Nan Chen,Ying Zhang,Qing Wang,Giacomo Cacciapaglia,Aldo Deandrea,Luca Panizzi
Physics , 2014, DOI: 10.1007/JHEP05(2014)088
Abstract: A spin-1 Z' particle as a single dark matter candidate is investigated by assuming that it does not directly couple to the Higgs boson and standard model fermions and does not mix with the photon and Z boson. The remaining dominant vertices are quartic Z'Z'ZZ and Z'Z'W+W-, which can induce effective Z'Z'q\bar{q} couplings through standard-model gauge-boson loops. We discuss constraints from the cosmological thermal relic density, and direct and indirect-detection experiments, and find that a dark Z' can only exist above the W boson mass threshold, and the effective quartic coupling of Z'Z'VV is bounded in the region of 10^{-3}~10^{-2}.
APEmille: a parallel processor in the teraflop range
Emanuele Panizzi
Physics , 1996, DOI: 10.1016/S0920-5632(96)00842-0
Abstract: APEmille is a SIMD parallel processor under development at the Italian National Institute for Nuclear Physics (INFN). APEmille is very well suited for Lattice QCD applications, both for its hardware characteristics and for its software and language features. APEmille is an array of custom arithmetic processors arranged on a tridimensional torus. The replicated processor is a pipelined VLIW device performing integer and single/double precision IEEE floating point operations. The processor is optimized for complex computations and has a peak performance of 528Mflop at 66MHz and of 800Mflop at 100MHz. In principle an array of 2048 nodes is able to break the Tflops barrier. A powerful programming language named TAO is provided and is highly optimized for QCD. A C++ compiler is foreseen. Specific data structures, operators and even statements can be defined by the user for each different application. Effort has been made to define the language constructs for QCD.
Duration of feeding and superficial and in-depth damage to soybean seed by selected species of stink bugs (Heteroptera: Pentatomidae)
Depieri, RA;Panizzi, AR;
Neotropical Entomology , 2011, DOI: 10.1590/S1519-566X2011000200007
Abstract: laboratory studies were conducted to compare duration of feeding and superficial and in-depth damage to soybean (glycine max) seeds by the southern green stink bug, nezara viridula (l.), the neotropical brown stink bug, euschistus heros (f.), the red-banded stink bug, piezodorus guildinii (westwood), and the green-belly stink bug, dichelops melacanthus (dallas). results indicated that feeding time was significantly longer for n. viridula (≈ 133 min) compared to e. heros and d. melacanthus (≈ 70 min), but not different from p. guildinii (≈ 103 min). there was a positive correlation between feeding time and the resulting damage for e. heros, n. viridula and p. guildinii (r2 > 0.80, p < 0.0001), but not for d. melacanthus (r2 = 0.1011, p = 0.1493). the deepest seed damage (2.0 mm) was made by p. guildinii and the shallowest (0.5 mm) by d. melacanthus. the depth of the seed damage by e. heros and n. viridula (0.8, 1.2 mm, respectively) was intermediate in comparison to the other species studied. feeding damage to the seed endosperm caused variable cell disruption and protein body dissolution, particularly when p. guildinii fed on seeds, suggesting that the deleterious action of salivary enzymes was greater for this bug compared to the others.
Possible egg positioning and gluing behavior by ovipositing southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae)
Panizzi, Ant?nio R.;
Neotropical Entomology , 2006, DOI: 10.1590/S1519-566X2006000100022
Abstract: from march 2002 to january 2004, a colony of southern green stink bug, nezara viridula (l.), was kept in the laboratory, and its oviposition behavior was observed. during oviposition, soon after the egg is expelled, the female touches the egg mass with the dorsal surface of the last tarsomere; this movement of one leg of the hind pair occurred once. this small component of the oviposition behavior of this pentatomid is little known and not yet fully understood; it may help to position and glue the newly deposited egg to the others.
Stink bugs on soybean in northeastern Brazil and a new record on the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae)
Neotropical Entomology , 2002, DOI: 10.1590/S1519-566X2002000200023
Abstract: during march-april 2001, a survey of pentatomids associated with soybean [glycine max (l.) merrill] was conducted at northeastern brazil (balsas county ? maranh?o state - latitude 7°31's, longitude 46°02'w). the majority of the phytophagous bugs (82.4%) belonged to the species euschistus heros (f.). other six species of bugs were collected in much lower numbers (<5.0%). among them, the exotic species, nezara viridula (l.), was intercepted in this area for the first time, expanding its distribution in the neotropical region.
Suboptimal nutrition and feeding behavior of hemipterans on less preferred plant food sources
Panizzi, Ant?nio R.;
Anais da Sociedade Entomológica do Brasil , 2000, DOI: 10.1590/S0301-80592000000100001
Abstract: phytophagous hemipterans (heteropterans) are, in general, polyphagous, feeding on a wide array of plants. among these, less preferred plant food sources are also explored as food and/or shelter. to illustrate this, i will discuss the feeding behavior of the southern green stink bug, nezara viridula (l.) (pentatomidae) on less preferred plants in northern paraná state. this bug feeds on several uncultivated-wild, and on cultivated plants, which are less preferred, changing its feeding behavior, from a typical seed/fruit sucking habit, to leaf/stem feeding, with consequences for its nymphal and adult performance. other seed suckers, such as euschistus heros (f.) and dichelops melacanthus (dallas) (pentatomidae) and neomegalotomus parvus westwood (alydidae), also change their feeding behavior from seeds to vegetative tissues (leaf, stems) when feeding on less preferred food plants. these and other mentioned examples demonstrate that for this feeding guild in particular, the less preferred food plant sources play an important role in the life history of these bugs, and that this fact is, in general, underestimated.
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