421 research outputs found
Updated bounds for neutrinoless double beta decay
We study the hypothesis that the Majorana mass of ordinary neutrinos dominates the rate of neutrinoless double beta decay. In particular, we update predictions from neutrino oscillations and we compare them with the results from
neutrinoless double beta decay searches. We also evaluate the impact of the quenching of the axial vector coupling constant in the nuclear medium, recently studied by Iachello et al. (Phys. Rev. C, 87 (2013) 014315)
Improving comfort and energy efficiency in a nursery school design process
A new nursery school in Milan was designed in the framework of a national research about low-energy buildings in temperate climates. The design of the case study started from a bioclimatic-approach, considering relationship between building envelope and sun path. In particular, orientation and morphology of the school are optimized (i.e. the building shapes improve solar control; classrooms and offices face South, services face North), the envelope is thermally efficient in both its opaque and transparent parts and overhangs are dimensioned to ensure solar gain in winter and to avoid direct solar radiation during summer season. A set of solutions for optimizing both energy efficiency and comfort conditions has been assessed. A floor radiant system, fed by a groundwater heat pump, has been foreseen and combined with a primary air ventilation system, equipped with heat recovery and managed by CO2 sensors. The school will be also equipped with opening window detectors and presence detectors, coupled by daylighting sensors, for controlling both illumination and thermal energy supply (hot water circulation in the radiant floor pipes and primary air cycle). Further, RE has been integrated in the design for hot water production by evacuated solar collectors placed on the roof of the higher block. As a result, a dynamic simulation made by VisualDOE software assessed 20 kWh/m² of energy heating demand: this value is below national standards foreseen from 2009, referring to the recent Italian implementation of the Energy Performance Building Directive (EPBD)
Neutrinoless Double Beta Decay: 2015 Review
The discovery of neutrino masses through the observation of oscillations boosted the importance of neutrinoless double beta decay (0 nu beta beta). In this paper, we review the main features of this process, underlining its key role from both the experimental and theoretical point of view. In particular, we contextualize the 0 nu beta beta in the panorama of lepton number violating processes, also assessing some possible particle physics mechanisms mediating the process. Since the 0 nu beta beta existence is correlated with neutrino masses, we also review the state of the art of the theoretical understanding of neutrinomasses. In the final part, the status of current 0 nu beta beta experiments is presented and the prospects for the future hunt for 0 nu beta beta are discussed. Also, experimental data coming from cosmological surveys are considered and their impact on 0 nu beta beta expectations is examined
Discovery probabilities of Majorana neutrinos based on cosmological data
We discuss the impact of the cosmological measurements on the predictions of the Majorana mass of the neutrinos, the parameter probed by neutrinoless double-beta decay experiments. Using a minimal set of assumptions, we quantify the probabilities of discovering neutrinoless double-beta decay and introduce a new graphical representation that could be of interest for the community
Discovery probabilities of Majorana neutrinos based on cosmological data
We discuss the impact of the cosmological measurements on the predictions of
the Majorana mass of the neutrinos, the parameter probed by neutrinoless
double-beta decay experiments. Using a minimal set of assumptions, we quantify
the probabilities of discovering neutrinoless double-beta decay and introduce a
new graphical representation that could be of interest for the community
Deep-underground search for the decay of 180m-Ta with an ultra-low-background HPGe detector
Ta is the longest-lived metastable state presently known. Its decay
has not been observed yet. In this work, we report a new result on the decay of
Ta obtained with a -g tantalum sample measured for d
with an ultra-low background HPGe detector in the STELLA laboratory of the
Laboratori Nazionali del Gran Sasso, in Italy. Before the measurement, the
sample has been stored deep-underground for ten years, resulting in subdominant
background contributions from cosmogenically activated Ta. We observe
no signal in the regions of interest and set half-life limits on the process
for the two channels EC and : yr and yr (% C. I.),
respectively. We also set the limit on the de-excitation / IC channel:
yr (% C. I.). These are, as of
now, the most stringent bounds on the decay of Ta worldwide.Comment: 8 pages, 7 figures, 4 table
The olivine-dominated composition of the Eureka family of Mars Trojan asteroids
We have used the XSHOOTER echelle spectrograph on the European Southern Obseratory (ESO) Very Large Telescope (VLT) to obtain UVB-VIS-NIR (ultraviolet-blue (UVB), visible (VIS) and near-infrared (NIR)) reflectance spectra of two members of the Eureka family of L5 Mars Trojans, in order to test a genetic relationship to Eureka. In addition to obtaining spectra, we also carried out VRI photometry of one of the VLT targets using the 2-m telescope at the Bulgarian National Astronomical Observatory - Rozhen and the two-channel focal reducer. We found that these asteroids belong to the olivine-dominated A, or Sa, taxonomic class. As Eureka itself is also an olivine-dominated asteroid, it is likely that all family asteroids share a common origin and composition. We discuss the significance of these results in terms of the origin of the martian Trojan population
The CUORE cryostat: an infrastructure for rare event searches at millikelvin temperatures
The CUORE experiment is the world's largest bolometric experiment. The
detector consists of an array of 988 TeO2 crystals, for a total mass of 742 kg.
CUORE is presently taking data at the Laboratori Nazionali del Gran Sasso,
Italy, searching for the neutrinoless double beta decay of 130Te. A large
custom cryogen-free cryostat allows reaching and maintaining a base temperature
of about 10 mK, required for the optimal operation of the detector. This
apparatus has been designed in order to achieve a low noise environment, with
minimal contribution to the radioactive background for the experiment. In this
paper, we present an overview of the CUORE cryostat, together with a
description of all its sub-systems, focusing on the solutions identified to
satisfy the stringent requirements. We briefly illustrate the various phases of
the cryostat commissioning and highlight the relevant steps and milestones
achieved each time. Finally, we describe the successful cooldown of CUORE
Search for Neutrinoless Double-Beta Decay of Te with CUORE-0
We report the results of a search for neutrinoless double-beta decay in a
9.8~kgyr exposure of Te using a bolometric detector array,
CUORE-0. The characteristic detector energy resolution and background level in
the region of interest are FWHM and ~counts/(keVkgyr), respectively. The
median 90%~C.L. lower-limit sensitivity of the experiment is and surpasses the sensitivity of previous searches. We find
no evidence for neutrinoless double-beta decay of Te and place a
Bayesian lower bound on the decay half-life, ~ at 90%~C.L. Combining CUORE-0 data with the 19.75~kgyr
exposure of Te from the Cuoricino experiment we obtain at 90%~C.L.~(Bayesian), the most stringent
limit to date on this half-life. Using a range of nuclear matrix element
estimates we interpret this as a limit on the effective Majorana neutrino mass,
-- .Comment: 6 pages, 5 figures, updated version as published in PR
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