21 research outputs found
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
The commissioning of the CUORE experiment: the mini-tower run
CUORE is a ton-scale experiment approaching the data taking phase in Gran Sasso National Laboratory. Its primary goal is to search for the neutrinoless double-beta decay in 130Te using 988 crystals of tellurim dioxide. The crystals are operated as bolometers at about 10 mK taking advantage of one of the largest dilution cryostat ever built. Concluded in March 2016, the cryostat commissioning consisted in a sequence of cool down runs each one integrating new parts of the apparatus. The last run was performed with the fully configured cryostat and the thermal load at 4 K reached the impressive mass of about 14 tons. During that run the base temperature of 6.3 mK was reached and maintained for more than 70 days. An array of 8 crystals, called mini-tower, was used to check bolometers operation, readout electronics and DAQ. Results will be presented in terms of cooling power, electronic noise, energy resolution and preliminary background measurements
Results from the Cuore Experiment
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO2 exposure of 86.3kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/ (keV kg yr). In this physics run, CUORE placed a lower limit on the decay half- life of neutrinoless double beta decay of 130Te > 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2vo3p decay with a resulting half- life of T2 2. [7.9 :- 0.1 (stat.) :- 0.2 (syst.)] x 10(20) yr which is the most precise measurement of the half- life and compatible with previous results
Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network
Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects
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Recoil ion charge state distribution following the beta(sup +) decay of {sup 21}Na
The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions
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Recoil ion charge state distribution following the beta(sup +) decay of {sup 21}Na
The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions
Synthesis of new heterometallic complexes by tin–sulfur bond cleavage of pySSnPh3 (pySH=pyridine-2-thiol) at triruthenium and triosmium centres
The ruthenium-tin complex, [Ru(2)(CO)(4)(SnPh(3))(2)(mu-pyS)(2)] (1), the main product of the oxidative-addition of pySSnPh(3) to Ru(3)(CO)(12) in refluxing benzene, is [Ru(CO)(2)(pyS)(SnPh(3))] synthon. It reacts with PPh(3) to give [Ru(CO)(2)(SnPh(3))(PPh(3))(kappa(2)-pyS)] (2) and further with Ru(3)(CO)(12) or [Os(3)(CO)(10)(NCMe)(2)] to afford the butterfly clusters [MRu(3)(CO)(12)(SnPh(3))(mu(3)-pyS)] (3, M=Ru; 4, M=Os). Direct addition of pySSnPh(3) to [Os(3)(CO)(10)(NCMe)(2)] at 70 degrees C gives [Os(3)(CO)(9)(SnPh(3))(mu(3)-pyS)] (5) as the only bimetallic compound, while with unsaturated [Os(3)(CO)(8){mu(3)-PPh(2)CH(2)P(Ph)C(6)H(4)}(mu-H)] the previously reported [Os(3)(CO)(8)(mu-pyS)(mu-H) (mu-dppm)] (6) and the new bimetallic cluster [Os(3)(CO)(7)(SnPh(3)){mu-Ph(2)PCH(2)P(Ph)C(6)H(4)}(mu-pyS)[(mu-H)] (7) are formed at 110 degrees C. Compounds 1, 2, 4, 5 and 7 have been characterized by X-ray diffraction studies. (C) 2010 Elsevier B.V. All rights reserved