The Large Enriched Germanium Experiment for Neutrinoless Double Beta Decay (LEGEND)

The observation of neutrinoless double-beta decay (0${\nu}{\beta}{\beta}$) would show that lepton number is violated, reveal that neutrinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of $\sim$0.1 count /(FWHM$\cdot$t$\cdot$yr) in the region of the signal. The current generation $^{76}$Ge experiments GERDA and the MAJORANA DEMONSTRATOR utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0${\nu}{\beta}{\beta}$ signal region of all 0${\nu}{\beta}{\beta}$ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale $^{76}$Ge experiment. The collaboration aims to develop a phased 0${\nu}{\beta}{\beta}$ experimental program with discovery potential at a half-life approaching or at $10^{28}$ years, using existing resources as appropriate to expedite physics results.Comment: Proceedings of the MEDEX'17 meeting (Prague, May 29 - June 2, 2017

Measurement of the top quark mass in the lepton plus jets final state with the matrix element method

We present a measurement of the top quark mass with the matrix element method in the lepton+jets final state. As the energy scale for calorimeter jets represents the dominant source of systematic uncertainty, the matrix element likelihood is extended by an additional parameter, which is defined as a global multiplicative factor applied to the standard energy scale. The top quark mass is obtained from a fit that yields the combined statistical and systematic jet energy scale uncertainty. Using a data set of 0.4fb-1 taken with the D0 experiment at Run II of the Fermilab Tevatron Collider, the mass of the top quark is measured using topological information to be: mtopℓ+jets(topo)=169. 2-7.4+5.0(stat+JES)-1.4+1.5(syst)GeV, and when information about identified b jets is included: mtopℓ+jets(b-tag)=170.3-4.5+4.1(stat+JES)-1.8+1.2(syst) GeV. The measurements yield a jet energy scale consistent with the reference scale. © 2006 The American Physical Society

Hall voltage collapse at filamentary current flow causing chaotic fluctuations in n-GaAs

Experimental investigations of the Hall effect at the occurrence of autonomous current fluctuations in high-purity n-GaAs epitaxial layers at low temperatures show that the transition to chaos is accompanied by intermittent collapses in the Hall voltage. This may represent the significant third mechanism for a transition into chaos according to the Ruelle-Takens-Newhouse scenario. Basically, space charges accumulated in the filament boundaries yield different impact ionization probabilities at opposite sides of the filament destabilizing the current flow and causing multimodal oscillation phenomena originating at the filament borders

Assessment of a lasersingulation process for Si-wafers with metallized back side and small die size

We report on the development of a dry lasersingulation process for Si-wafers with back side metallization targeting small die sizes below 0.07 mm2. The dicing technology aims at improved manufacturing of diodes with thicknesses ranging from approx. 100 µm to 150 µm, die sizes down to 230 x 230 µm2 and metallized back side metallization layers used for solder die attach. We discuss the impact of the laser process on subsequent assembly processes as well as on the die itself. Particular emphasis is set on the laser induced modification of the mechanical properties within the wafer, e. g. the reduction of the die strength. For the wafer technology under evaluation, the laser process is considered to be superior to standard blade dicing approaches

The Gerda experiment for the search of 0νββ decay in 76Ge

The Gerda collaboration is performing a search for neutrinoless double beta decay of Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R&D phase. © 2013 The Author(s). 7

The Gerda experiment for the search of 0νββ decay in 76Ge

The Gerda collaboration is performing a search for neutrinoless double beta decay of 76Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R&D phase. © 2013 The Author(s)

Genomic composition and dynamics among Methanomicrobiales predict adaptation to contrasting environments

Members of the order Methanomicrobiales are abundant, and sometimes dominant, hydrogenotrophic (H(2)-CO(2) utilizing) methanoarchaea in a broad range of anoxic habitats. Despite their key roles in greenhouse gas emissions and waste conversion to methane, little is known about the physiological and genomic bases for their widespread distribution and abundance. In this study, we compared the genomes of nine diverse Methanomicrobiales strains, examined their pangenomes, reconstructed gene flow and identified genes putatively mediating their success across different habitats. Most strains slowly increased gene content whereas one, Methanocorpusculum labreanum, evidenced genome downsizing. Peat-dwelling Methanomicrobiales showed adaptations centered on improved transport of scarce inorganic nutrients and likely use H(+) rather than Na(+) transmembrane chemiosmotic gradients during energy conservation. In contrast, other Methanomicrobiales show the potential to concurrently use Na(+) and H(+) chemiosmotic gradients. Analyses also revealed that the Methanomicrobiales lack a canonical electron bifurcation system (MvhABGD) known to produce low potential electrons in other orders of hydrogenotrophic methanogens. Additional putative differences in anabolic metabolism suggest that the dynamics of interspecies electron transfer from Methanomicrobiales syntrophic partners can also differ considerably. Altogether, these findings suggest profound differences in electron trafficking in the Methanomicrobiales compared with other hydrogenotrophs, and warrant further functional evaluations

The GERDA experiment for the search of 0νββ decay in ^{76}Ge

The Gerda collaboration is performing a search for neutrinoless double beta decay of 76Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R&D phase