40 research outputs found
First Results from the AMoRE-Pilot neutrinoless double beta decay experiment
The Advanced Molybdenum-based Rare process Experiment (AMoRE) aims to search
for neutrinoless double beta decay (0) of Mo with
100 kg of Mo-enriched molybdenum embedded in cryogenic detectors
with a dual heat and light readout. At the current, pilot stage of the AMoRE
project we employ six calcium molybdate crystals with a total mass of 1.9 kg,
produced from Ca-depleted calcium and Mo-enriched molybdenum
(CaMoO). The simultaneous detection of
heat(phonon) and scintillation (photon) signals is realized with high
resolution metallic magnetic calorimeter sensors that operate at milli-Kelvin
temperatures. This stage of the project is carried out in the Yangyang
underground laboratory at a depth of 700 m. We report first results from the
AMoRE-Pilot search with a 111 kgd live exposure of
CaMoO crystals. No evidence for
decay of Mo is found, and a upper limit is set for the
half-life of 0 of Mo of y at 90% C.L.. This limit corresponds to an effective
Majorana neutrino mass limit in the range eV
The Coal Farms of the Late Paleozoic
The assembly of the supercontinent Pangea resulted in a paleoequatorial region known as Euramerica, a northern mid-to-high latitude region called Angara, and a southern high paleolatitudinal region named Gondwana. Forested peat swamps, extending over hundreds of thousands of square kilometers, grew across this supercontinent during the Mississippian, Pennsylvanian, and Permian in response to changes in global climate. The plants that accumulated as peat do not belong to the plant groups prominent across today’s landscapes. Rather, the plant groups of the Late Paleozoic that are responsible for most of the biomass in these swamps belong to the fern and fern allies: club mosses, horsetails, and true ferns. Gymnosperms of various systematic affinity play a subdominant role in these swamps, and these plants were more common outside of wetland settings. It is not until the Permian when these seed-bearing plants become more dominant. Due to tectonic activity associated with assembling the supercontinent, including earthquakes and volcanic ashfall, a number of these forests were buried in their growth positions. These instants in time, often referred to as T0 assemblages, provide insight into the paleoecological relationships that operated therein. Details of T0 localities through the Late Paleozoic demonstrate that the plants, and plant communities, of the coal forests are non-analogs to our modern world. Analysis of changing vegetational patterns from the Mississippian into the Permian documents the response of landscapes to overall changes in Earth Systems under icehouse to hothouse conditions