African ancestry of New World, Bemisia tabaci-whitefly species

Bemisia tabaci whitefly species are some of the world’s most devastating agricultural pests and plant-virus disease vectors. Elucidation of the phylogenetic relationships in the group is the basis for understanding their evolution, biogeography, gene-functions and development of novel control technologies. We report here the discovery of five new Sub-Saharan Africa (SSA) B. tabaci putative species, using the partial mitochondrial cytochrome oxidase 1 gene: SSA9, SSA10, SSA11, SSA12 and SSA13. Two of them, SSA10 and SSA11 clustered with the New World species and shared 84.8‒86.5% sequence identities. SSA10 and SSA11 provide new evidence for a close evolutionary link between the Old and New World species. Re-analysis of the evolutionary history of B. tabaci species group indicates that the new African species (SSA10 and SSA11) diverged from the New World clade c. 25 million years ago. The new putative species enable us to: (i) re-evaluate current models of B. tabaci evolution, (ii) recognise increased diversity within this cryptic species group and (iii) re-estimate divergence dates in evolutionary time

Search for invisible modes of nucleon decay in water with the SNO+ detector

This paper reports results from a search for nucleon decay through invisible modes, where no visible energy is directly deposited during the decay itself, during the initial water phase of SNO+. However, such decays within the oxygen nucleus would produce an excited daughter that would subsequently deexcite, often emitting detectable gamma rays. A search for such gamma rays yields limits of 2.5×1029  y at 90% Bayesian credibility level (with a prior uniform in rate) for the partial lifetime of the neutron, and 3.6×1029  y for the partial lifetime of the proton, the latter a 70% improvement on the previous limit from SNO. We also present partial lifetime limits for invisible dinucleon modes of 1.3×1028  y for nn, 2.6×1028  y for pn and 4.7×1028  y for pp, an improvement over existing limits by close to 3 orders of magnitude for the latter two

Development, characterisation, and deployment of the SNO+ liquid scintillator

A liquid scintillator consisting of linear alkylbenzene as the solvent and 2,5-diphenyloxazole as the fluor was developed for the SNO+ experiment. This mixture was chosen as it is compatible with acrylic and has a competitive light yield to pre-existing liquid scintillators while conferring other advantages including longer attenuation lengths, superior safety characteristics, chemical simplicity, ease of handling, and logistical availability. Its properties have been extensively characterized and are presented here. This liquid scintillator is now used in several neutrino physics experiments in addition to SNO+

Search for invisible modes of nucleon decay in water with the SNO+ detector

This paper reports results from a search for nucleon decay through invisible modes, where no visible energy is directly deposited during the decay itself, during the initial water phase of SNO+. However, such decays within the oxygen nucleus would produce an excited daughter that would subsequently deexcite, often emitting detectable gamma rays. A search for such gamma rays yields limits of 2.5×1029 y at 90% Bayesian credibility level (with a prior uniform in rate) for the partial lifetime of the neutron, and 3.6×1029 y for the partial lifetime of the proton, the latter a 70% improvement on the previous limit from SNO. We also present partial lifetime limits for invisible dinucleon modes of 1.3×1028 y for nn, 2.6×1028 y for pn and 4.7×1028 y for pp, an improvement over existing limits by close to 3 orders of magnitude for the latter two

Current Status and Future Prospects of the SNO+ Experiment

SNO+ is a large liquid scintillator-based experiment located 2 km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12 m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0ββ) of Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55-133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The 0νββ Phase I is foreseen for 2017. 130 13

Search for invisible modes of nucleon decay in water with the SNO+ detector

This paper reports results from a search for nucleon decay through invisible modes, where no visible energy is directly deposited during the decay itself, during the initial water phase of SNO+. However, such decays within the oxygen nucleus would produce an excited daughter that would subsequently deexcite, often emitting detectable gamma rays. A search for such gamma rays yields limits of 2.5×1029 y at 90% Bayesian credibility level (with a prior uniform in rate) for the partial lifetime of the neutron, and 3.6×1029 y for the partial lifetime of the proton, the latter a 70% improvement on the previous limit from SNO. We also present partial lifetime limits for invisible dinucleon modes of 1.3×1028 y for nn, 2.6×1028 y for pn and 4.7×1028 y for pp, an improvement over existing limits by close to 3 orders of magnitude for the latter two

Current Status and Future Prospects of the SNO+ Experiment

SNO+ is a large liquid scintillator-based experiment located 2 km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12 m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0ββ) of 130Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of 130Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55-133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The 0νββ Phase I is foreseen for 2017

Silicon detectors for the sLHC

In current particle physics experiments, silicon strip detectors are widely used as part of the inner tracking layers. A foreseeable large-scale application for such detectors consists of the luminosity upgrade of the Large Hadron Collider (LHC), the super-LHC or sLHC, where silicon detectors with extreme radiation hardness are required. The mission statement of the CERN RD50 Collaboration is the development of radiation-hard semiconductor devices for very high luminosity colliders. As a consequence, the aim of the RandD programme presented in this article is to develop silicon particle detectors able to operate at sLHC conditions. Research has progressed in different areas, such as defect characterisation, defect engineering and full detector systems. Recent results from these areas will be presented. This includes in particular an improved understanding of the macroscopic changes of the effective doping concentration based on identification of the individual microscopic defects, results from irradiation with a mix of different particle types as expected for the sLHC, and the observation of charge multiplication effects in heavily irradiated detectors at very high bias voltages. © 2011 Elsevier B.V

Silicon detectors for the sLHC

In current particle physics experiments, silicon strip detectors are widely used as part of the inner tracking layers. A foreseeable large-scale application for such detectors consists of the luminosity upgrade of the Large Hadron Collider (LHC), the super-LHC or sLHC, where silicon detectors with extreme radiation hardness are required. The mission statement of the CERN RD50 Collaboration is the development of radiation-hard semiconductor devices for very high luminosity colliders. As a consequence, the aim of the R&D programme presented in this article is to develop silicon particle detectors able to operate at sLHC conditions. Research has progressed in different areas, such as defect characterisation, defect engineering and full detector systems. Recent results from these areas will be presented. This includes in particular an improved understanding of the macroscopic changes of the effective doping concentration based on identification of the individual microscopic defects, results from irradiation with a mix of different particle types as expected for the sLHC, and the observation of charge multiplication effects in heavily irradiated detectors at very high bias voltages. (C) 2011 Elsevier B.V. All rights reserved