Lepton number, black hole entropy and 10 to the 32 copies of the Standard Model

Lepton number violating processes are a typical problem in theories with a low quantum gravity scale. In this paper we examine lepton number violation (LNV) in theories with a saturated black hole bound on a large number of species. Such theories have been advocated recently as a possible solution to the hierarchy problem and an explanation of the smallness of neutrino masses. Naively one would expect black holes to introduce TeV scale LNV operators, thus generating unacceptably large rates of LNV processes. We show, however, that this does not happen in this scenario due to a complicated compensation mechanism between contributions of different Majorana neutrino states to these processes. As a result rates of LNV processes are extremely small and far beyond experimental reach, at least for the left-handed neutrino states.Comment: 6 pages, 3 figures, to appear in Proc. PASCOS 2010, Valencia, Spai

Lepton number violation in theories with a large number of Standard Model copies

We examine lepton number violation (LNV) in theories with a saturated black hole bound on a large number of species. Such theories have been advocated recently as a possible solution to the hierarchy problem and an explanation of the smallness of neutrino masses. The violation of lepton number can be a potential phenomenological problem of this N-copy extension of the Standard Model as due to the low quantum gravity scale black holes may induce TeV scale LNV operators generating unacceptably large rates of LNV processes. We show, however, that this does not happen in this scenario due to a specific compensation mechanism between contributions of different Majorana neutrino states to these processes. As a result rates of LNV processes are extremely small and far beyond experimental reach, at least for the left-handed neutrino states.Comment: 5 pages, 3 figure

Lepton number violation phenomenology of d=7 neutrino mass models

We study the phenomenology of d=7 1-loop neutrino mass models. All models in this particular class require the existence of several new $SU(2)_L$ multiplets, both scalar and fermionic, and thus predict a rich phenomenology at the LHC. The observed neutrino masses and mixings can easily be fitted in these models. Interestingly, despite the smallness of the observed neutrino masses, some particular lepton number violating (LNV) final states can arise with observable branching ratios. These LNV final states consists of leptons and gauge bosons with high multiplicities, such as 4l+4W, 6l+2W, etc. We study current constraints on these models from upper bounds on charged lepton flavour violating decays, existing lepton number conserving searches at the LHC and discuss possible future LNV searches

Insight from the 5th World Water Forum on Securing Water for Food and Ecosystems in Africa : Report on BOCI Project BO-10-004-003: Water Conventions

Water scarcity is considered to be one of the largest threats for many parts of Africa. Under water scarce conditions reducing the consumption of water and preventing pollution of accessible water resources is essential. Combating water scarcity in both dimensions of quality and quantity is of special relevance for the LNV priority regions (including those in Water Mondiaal). Future LNV policies to address food security in Africa will affect the use, spread and fate of agrochemicals as well. Very little information is available on how this might effect the ecosystem approach (including biodiversity, increased resilience, and multiple-use potential) in land use plannin

Neutrino masses in lepton number violating mSUGRA

In SUSY models which violate R-parity, there exist trilinear lepton number violating (LNV) operators which can lead to neutrino masses. If these operators are defined at the unification scale, the renormalization group flow becomes important and generally leads to one neutrino mass much heavier than the others. We study, in a minimal supergravity (mSUGRA) set-up with two trilinear LNV operators and three charged lepton mixing angles, numerically how these parameters may be arranged to be compatible with neutrino oscillation data, and discuss some phenomenological observations.Comment: 3 pages, 2 figures. Talk given at SUSY08. To be published in the Conference Proceeding

Neutrinoless Double Beta Decay and Lepton Flavor Violation

We point out that extensions of the Standard Model with low scale (~TeV) lepton number violation (LNV) generally lead to a pattern of lepton flavor violation (LFV) experimentally distinguishable from the one implied by models with GUT scale LNV. As a consequence, muon LFV processes provide a powerful diagnostic tool to determine whether or not the effective neutrino mass can be deduced from the rate of neutrinoless double beta decay. We discuss the role of \mu -> e \gamma and \mu -> e conversion in nuclei, which will be studied with high sensitivity in forthcoming experiments.Comment: 4 pages, 3 figure

Isolates of Liao Ning Virus from Wild-Caught Mosquitoes in the Xinjiang Province of China in 2005

Liao ning virus (LNV) is related to Banna virus, a known human-pathogen present in south-east Asia. Both viruses belong to the genus Seadornavirus, family Reoviridae. LNV causes lethal haemorrhage in experimentally infected mice. Twenty seven isolates of LNV were made from mosquitoes collected in different locations within the Xinjiang province of north-western China during 2005. These mosquitoes were caught in the accommodation of human patients with febrile manifestations, or in animal barns where sheep represent the main livestock species. The regions where LNV was isolated are affected by seasonal encephalitis, but are free of Japanese encephalitis (JE). Genome segment 10 (Seg-10) (encoding cell-attachment and serotype-determining protein VP10) and Seg-12 (encoding non-structural protein VP12) were sequenced for multiple LNV isolates. Phylogenetic analyses showed a less homogenous Seg-10 gene pool, as compared to segment 12. However, all of these isolates appear to belong to LNV type-1. These data suggest a relatively recent introduction of LNV into Xinjiang province, with substitution rates for LNV Seg-10 and Seg-12, respectively, of 2.29×10−4 and 1.57×10−4 substitutions/nt/year. These substitution rates are similar to those estimated for other dsRNA viruses. Our data indicate that the history of LNV is characterized by a lack of demographic fluctuations. However, a decline in the LNV population in the late 1980s - early 1990s, was indicated by data for both Seg-10 and Seg-12. Data also suggest a beginning of an expansion in the late 1990s as inferred from Seg-12 skyline plot

Exotic coloured fermions and lepton number violation at the LHC

Majorana neutrino mass models with a scale of lepton number violation (LNV) of order TeV potentially lead to signals at the LHC. Here, we consider an extension of the standard model with a coloured octet fermion and a scalar leptoquark. This model generates neutrino masses at 2-loop order. We make a detailed MonteCarlo study of the LNV signal at the LHC in this model, including a simulation of standard model backgrounds. Our forecast predicts that the LHC with 300/fb should be able to probe this model up to colour octet fermion masses in the range of (2.6-2.7) TeV, depending on the lepton flavour of the final state.Comment: 14 pages, 2 figure