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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

DUNE’s Potential to Search for Neutrinoless Double Beta Decay

Neutrinoless double beta decay is a forbidden process by the standard model due to a violation of lepton number and could be piece of the matter/anti-matter asymmetry puzzle. Its rarity makes it very difficult to search for, but if found could aid in figuring out the mass hierarchy. The idea is to take advantage of DUNE's size and capabilities to attempt to detect the decay by doping the liquid argon with Xenon, a candidate isotope for this decay. Thus, we need to know whether this search is feasible within DUNE’s framework

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Status Update of the Majorana Demonstrator Neutrinoless Double Beta Decay Experiment

Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The Majorana Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in 76Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched detectors.

Majorana Demonstrator↗
DOE OSTI2018

Status Update of the MAJORANA DEMONSTRATOR Neutrinoless Double Beta Decay Experiment

Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The \textsc{Majorana} Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in $^{76}$Ge. The \textsc{Majorana Demonstrator}, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in $^{76}$Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched detectors.

Gruszko, J↗
DOE OSTI2015

{beta} decay of 129Cd and excited states in 129In

The β decay of Cd 129 , produced in the relativistic fission of a U 238 beam, was experimentally studied at the RIBF facility at the RIKEN Nishina Center. From the γ radiation emitted after the β decays, a level scheme of In 129 was established comprising 31 excited states and 69 γ -ray transitions. The experimentally determined level energies are compared to state-of-the-art shell-model calculations. The half-lives of the two β -decaying states in Cd 129 were deduced and the β feeding to excited states in In 129 were analyzed. It is found that, as in most cases in the Z<50 , N≤82 region, both decays are dominated by the ν0g 7/2 →π0g 9/2 Gamow–Teller transition, although the contribution of first-forbidden transitions cannot be neglected.

Taprogge, J.↗
DOE OSTI2018

Study of Reconstructed 39 Ar Beta Decays at the MicroBooNE Detector

In atmospheric argon, 39 Ar beta decays occur at a rate of roughly one Becquerel per kilogram; as a result, large liquid argon time projection chambers (LArTPCs) see plentiful amounts of these decays in each event readout window. These 39 Ar beta decays can provide a variety of different uses in LArTPC experiments. They allow for the study of reconstructing point-like ionization charge deposition in the detector, which is relevant for the reconstruction of supernova neutrino interactions. The point-like topology and well-known energy spectrum of 39 Ar beta decays also provides a unique handle for calibrations. Presented here is the first study of reconstructing 39 Ar beta decays in the MicroBooNE LArTPC. The spectrum of reconstructed electron energies from 39 Ar beta decays, measured using raw TPC waveforms, is found to have a similar end point as the predicted distribution. Additionally, the signal shapes of reconstructed 39 Ar beta decay candidates are used to validate the collection plane wire field response.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

The MAJORANA DEMONSTRATOR: A Search for Neutrino less Double-beta Decay of Ge-76

Neutrino less double-beta (Ov beta beta) decay is a hypothesized process where in some even-even nuclei it might be possible for two neutrons to simultaneously decay into two protons and two electrons without emitting neutrinos. This is possible only if neutrinos are Majorana particles, i.e. fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and might play a role in the matter-antimatter asymmetry in the universe. The observation of neutrinoless double-beta decay would also provide complementary information related to neutrino masses. The MAJORANA Collaboration is constructing the MAJORANA DEMONSTRATOR, with a total of 40-kg Germanium detectors, to search for the Ov beta beta decay of Ge-76 and to demonstrate a background rate at or below 3 counts/ (ROI.t.y) in the 4 keV region of interest (ROT) around the 2039 keV Q-value for Ge-76 Ov beta beta decay. In this paper, we discuss the physics of neutrinoless double beta decay and then focus on the MAJORANA DEMONSTRATOR, including its design and approach to achieve ultra-low backgrounds and the status of the experiment.

Xu, W.↗
DOE OSTI2014

New precision measurements of free neutron beta decay with cold neutrons

Precision measurements in free neutron beta decay serve to determine the coupling constants of beta decay, and offer several stringent tests of the standard model. This study describes the free neutron beta decay program planned for the Fundamental Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and finally puts it into the context of other recent and planned measurements of neutron beta decay observables.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Searching for beyond the Standard Model physics using the improved description of 100 Mo $2\nu \beta \beta$ decay spectral shape with CUPID-Mo

The current experiments searching for neutrinoless double-β ($0\nu \beta \beta$) decay also collect large statistics of Standard Model allowed two-neutrino double-β ($2\nu \beta \beta$ ) decay events. These can be used to search for Beyond Standard Model (BSM) physics via $2\nu \beta \beta$ decay spectral distortions. 100 Mo has a natural advantage due to its relatively short half-life, allowing higher $2\nu \beta \beta$ decay statistics at equal exposures compared to the other isotopes. We demonstrate the potential of the dual read-out bolometric technique exploiting a 100 Mo exposure of 1.47 kg years, acquired in the CUPID-Mo experiment at the Modane underground laboratory (France). We set limits on $0\nu \beta \beta$ decays with the emission of one or more Majorons, on $2\nu \beta \beta$ decay with Lorentz violation, and $2\nu \beta \beta$ decay with a sterile neutrino emission. In this analysis, we investigate the systematic uncertainty induced by modeling the $2\nu \beta \beta$ decay spectral shape parameterized through an improved model, an effect never considered before. This work motivates searches for BSM processes in the upcoming CUPID experiment, which will collect the largest amount of $2\nu \beta \beta$ decay events among the next-generation experiments.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Results of the double beta decay experiment NEMO-3

The double beta decay experiment NEMO-3 has taken data from February 2003 to January 2011. The two-neutrino decay half lives were measured for seven different isotopes ({sup 100}Mo, {sup 82}Se, {sup 116}Cd, {sup 150}Nd, {sup 96}Zr, {sup 48}Ca and {sup 130}Te). No evidence for neutrinoless double beta decay is observed. The 0νββ half-life limits are found to be T{sub 1/2}{sup 0ν}({sup 100}Mo)>1.0×10{sup 24}yr(90%C.L.) and T{sub 1/2}{sup 0ν}({sup 82}Se)>3.2×10{sup 23}yr(90%C.L.)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Effect of complex configurations on the description of properties of {sup 132}Sn beta decay

Gamow–Teller transitions in the beta decay of the {sup 132}Sn neutron-rich nucleus was described microscopically. The coupling of one- and two-phonon components of the wave functions was taken into account on the basis of Skyrme interactions featuring various contributions of the tensor component. A separable approximation of the particle—hole interaction made it possible tohole interaction perform calculations in a large configuration space. It was shown that an increase in the strength of the neutron—proton tensor interaction led to an increase in the energy of Gamow—Teller transitions. In addition, a decrease in the {sup 132}Sn half-life with respect to beta decay was obtained.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Review of modern double beta decay experiments

The review of modern experiments on search and studying of double beta decay processes is done. Results of the most sensitive current experiments are discussed. The main attention is paid to EXO-200, KamLAND-Zen, GERDA-I and CUORE-0 experiments. Modern values of T{sub 1/2}(2ν) and best present limits on neutrinoless double beta decay and double beta decay with Majoron emission are presented. Conservative limits on effective mass of a Majorana neutrino (〈m{sub ν}〉 < 0.46 eV) and a coupling constant of Majoron to neutrino (〈g{sub ee}〉 < 1.3 · 10{sup −5}) are obtained. Prospects of search for neutrinoless double beta decay in new experiments with sensitivity to 〈m{sub ν}〉 at the level of ∼ 0.01-0.1 eV are discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Recoil ions from the β decay of Sb 134 confined in a Paul trap [Study of Recoil ions from the β decay of Sb 134 using the Beta-decay Paul trap]

The low-energy recoiling ions from the β decay of 134 Sb were studied by using the Beta-decay Paul Trap. Using this apparatus, singly charged ions were suspended in vacuum at the center of a detector array used to detect emitted β particles, γ rays, and recoil ions in coincidence. The recoil ions emerge from the trap with negligible scattering, allowing β-decay properties and the charge-state distribution of the daughter ions to be determined from the β-ion coincidences. First-forbidden β-decay theory predicts a β–ν correlation coefficient of nearly unity for the 0 – to 0 + transition from the ground state of 134 Sb to the ground state of 134 Te. Although this transition was expected to have a nearly 100% branching ratio, an additional 17.2(52)% of the β-decay strength must populate high-lying excited states to obtain an angular correlation consistent with unity. As a result, the extracted charge-state distribution of the recoiling ions was compared with existing β-decay results and the average charge state was found to be consistent with the results from lighter nuclei.

42 ENGINEERING↗
DOE OSTI2013

Forbidden unique beta-decays and neutrino mass

The measurement of the electron spectrum in beta-decays provides a robust direct determination of the values of neutrino masses. The planned rhenium beta-decay experiment, called the “Microcalorimeter Arrays for a Rhenium Experiment” (MARE), might probe the absolute mass scale of neutrinos with the same sensitivity as the Karlsruhe tritium neutrino mass (KATRIN) experiment, which is expected to collect data in a near future. In this contribution we discuss the spectrum of emitted electrons close to the end point in the case of the first unique forbidden beta-decay of {sup 79}Se, {sup 107}Pd and {sup 187}Re. It is found that the p{sub 3/2}-wave emission dominates over the s{sub 1/2}-wave. It is shown that the Kurie plot near the end point is within a good accuracy linear in the limit of massless neutrinos like the Kurie plot of the superallowed beta-decay of {sup 3}H.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Background discrimination for neutrinoless double beta decay in liquid xenon using Cherenkov light

Neutrinoless double beta decays in liquid xenon produce a significant amount of Cherenkov light, with a photon number and angular distribution that distinguishes these events from common backgrounds. A GEANT4 simulation was used to simulate Cherenkov photon production and measurement in a liquid xenon detector and a multilayer perceptron was used to analyze the resulting distributions to classify events based on their Cherenkov photons. Our results show here that a modest improvement in the sensitivity of neutrinoless double beta decay searches is possible using this technique, but the kinematics of the neutrinoless double beta decay and electron scattering in liquid xenon substantially limit this approach.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

New Technique for Barium Daughter Ion Identification in a Liquid Xe-136 Double Beta Decay Experiment

This work addresses long-standing issues of fundamental interest in elementary particle physics. The most important outcome of this work is a new limit on neutrinoless double beta decay. This is an extremely rare and long-sought-after type of radioactive decay. If discovered, it would require changes in the standard model of the elementary constituents of matter, and would prove that neutrinos and antineutrinos are the same, a revolutionary concept in particle physics. Neutrinos are major components of the matter in the universe that are so small and so weakly interacting with other matter that their masses have not yet been discovered. A discovery of neutrinoless double beta decay could help determine the neutrino masses. An important outcome of the work on this project was the Colorado State University role in operating the EXO-200 neutrinoless double beta decay experiment and in analysis of the data from this experiment. One type of double beta decay of the isotope 136 Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world’s best sensitivity of 1.9x10 25 year half-life was obtained. This result rules out a previous claim of a positive result in a different isotope. This work also establishes that the masses of the neutrinos are less than one millionth of that of electrons. A unique EXO-200 analysis, in which the CSU group had a leading role, has established for the first time ever in a liquid noble gas the fraction of daughter atoms from alpha and beta decay that are ionized. This result has important impact on other pending studies, including nucleon decay and barium tagging. Novel additional discoveries include multiphoton ionization of liquid xenon with UV pulsed lasers, which may find application in calibration of future noble liquid detectors, and studies of association and dissociation reactions of Ba + ions in gaseous xenon. Through this project, we are substantially closer to demonstrating “barium tagging”, i.e., detection of single daughter 136 Ba atoms from 136 Xe double beta decay. Milestones achieved include obtaining spectra of small numbers of Ba atoms and cryoprobe advances toward trapping single 136 Ba atoms in solid xenon and probe extraction for detection. One of the other benefits to society is the training of six Ph.D. students in a variety of state-of-the-art technologies, half under primary support of this grant and half with partial support, with four finishing their Ph.D. degrees and two well on their way.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Beta Decay of Molecular Tritium

The beta decay of tritium in the form of molecular T 2 is the basis of sensitive experiments to measure neutrino mass. The final-state electronic, vibrational, and rotational excitations modify the beta spectrum significantly and are obtained from theory. We further determine measurements of the branching ratios to specific ionization states for the isotopolog HT. Two earlier, concordant measurements gave branching ratios of HT to the bound HHe + ion of 89.5% and 93.2%, in sharp disagreement with the theoretical prediction of 55%–57%, raising concerns about the theory’s reliability in neutrino mass experiments. Our finding, 56.5(6)%, is compatible with the theoretical expectation and disagrees strongly with the previous measurements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Neutrinoless Double-Beta Decay Investigations of 82Se Using Three Shell Model Hamiltonians

Neutrinoless double-beta decay is considered one of the most promising processes that would help clarify some of the symmetry-breaking problems in our understanding of the observable universe. Recent studies of neutrinoless double-beta decay matrix elements have employed statistical approaches based on modified shell model effective Hamiltonians for 48Ca (Phys. Rev. C 106, 054302 (2022)) and 136Xe (Phys. Rev. C 107, 045501 (2023)). The analyses rely on inducing perturbations in the starting effective Hamiltonians to observe the behavior of a wide range of observables, besides the 0νββ) NME, that are compared with experimental data. Following a Bayesian model averaging approach, the range of probable values for the neutrinoless double-beta decay matrix elements is presented. In this paper, we present a similar study for 82Se, which is described in the same model space as 76Ge that is under experimental observation. Due to its faster calculation time compared to 76Ge, 82Se can be used as an appropriate substitute in our complex statistical study. Using the calculations performed for the statistical analysis of the neutrinoless double-beta decay matrix elements, we also search for the correlations between the observables that we can compare to experimental data.

Science & Technology - Other Topics↗
DOE OSTI2020

Improved Limit on Neutrinoless Double-Beta Decay in Te 130 with CUORE

We report new results from the search for neutrinoless double-beta decay in $^{130}$Te with the CUORE detector. This search benefits from a four-fold increase in exposure, lower trigger thresholds and analysis improvements relative to our previous results. We observe a background of $(1.38\pm0.07)\cdot10^{-2}$ counts$/($keV$\cdot$kg$\cdot$yr$)$ in the $0\nu\beta\beta$ decay region of interest and, with a total exposure of 372.5 kg$\cdot$yr, we attain a median exclusion sensitivity of $1.7\cdot10^{25}$ yr. We find no evidence for $0\nu\beta\beta$ decay and set a $90\%$ CI Bayesian lower limit of $3.2\cdot10^{25}$ yr on the $^{130}$Te half-life for this process. In the hypothesis that $0\nu\beta\beta$ decay is mediated by light Majorana neutrinos, this results in an upper limit on the effective Majorana mass of 75-350 meV, depending on the nuclear matrix elements used.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗