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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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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Application of nuclear density functionals to lepton number violating weak processes

We present an application of energy density functional methods with the Gogny interaction to the calculation of nuclear matrix elements (NME) for neutrinoless double beta decay and double electron capture. Beyond mean field effects have been included by particle number and angular momentum restoration and shape mixing within the generator coordinate method (GCM) framework. We analyze in detail the NME for {sup 116}Cd nucleus which is one of the most promising candidates to detect neutrinoless double beta decay.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

SMWDs as SGRs/AXPs and the lepton number violation

Possible nature of strongly magnetized white dwarfs (SMWDs) is studied. It is shown that for relatively low values of the equatorial surface magnetic field B ∼ 10{sup 9} − 10{sup 11} G they can be good candidates for soft gamma-ray repeaters and anomalous X-ray pulsars (SGRs/AXPs). For the case of iron SMWDs the influence of a neutrinoless electron to positron conversion on the SGRs/AXPs luminosity is estimated.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2026

First Results on the Search for Lepton Number Violating Neutrinoless Double-𝛽 Decay with the LEGEND-200 Experiment

The LEGEND Collaboration is searching for neutrinoless double-beta (0⁢𝜈⁢𝛽⁢𝛽) decay by operating high-purity germanium detectors enriched in 76 Ge in a low-background liquid argon environment. Building on key technological innovations from the GERmanium Detector Array (GERDA) experiment and the MAJORANA DEMONSTRATOR experiment, LEGEND-200 has performed a first 0⁢𝜈⁢𝛽⁢𝛽 decay search based on 61.0 kg yr of data. Over half of this exposure comes from our highest performing detectors, including newly developed inverted-coaxial detectors, and is characterized by an estimated background level of 0.5$^{+0.3}_{−0.2}$ ⁢cts/(keV ton yr) in the 0⁢𝜈⁢𝛽⁢𝛽 decay signal region. A combined analysis of data from GERDA, the MAJORANA DEMONSTRATOR, and LEGEND-200, characterized by a 90% confidence level exclusion sensitivity of 2.8 ×10 26 yr on the half-life of 0⁢𝜈⁢𝛽⁢𝛽 decay, reveals no evidence for a signal and sets a new observed lower limit at 𝑇$^{⁢0𝜈}_{1/2}$ > 1.9 × 10 26 yr (90% confidence level). Assuming the decay is mediated by Majorana neutrinos, this corresponds to an upper limit on the effective Majorana mass in the range 𝑚 𝛽⁢𝛽 < 75–200 meV, depending on the adopted nuclear matrix element.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

First Results from CUORE: A Search for Lepton Number Violation via 0 ν β β Decay of Te 130

The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a significant advancement in this technology, and in this work we apply it for the first time to a high-sensitivity search for a lepton-numberviolating process: 130 Te neutrinoless double-beta decay. Examining a total TeO 2 exposure of 86.3 kg yr, characterized by an effective energy resolution of d7.7 ± 0.5T keV FWHM and a background in the region of interest of d0.014 ± 0.002T counts=dkeV kg yrT, we find no evidence for neutrinoless double-beta decay. Including systematic uncertainties, we place a lower limit on the decay half-life of T 0ν 1/2 ( 130 Te) > 1.3 × 10 25 yr (90% C.L.); the median statistical sensitivity of this search is 7.0 × 10 24 yr. Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find T 0ν 1/2 ( 130 Te) > 1.5 × 10 25 yr (90% C.L.), which is the most stringent limit to date on this decay. Interpreting this result as a limit on the effective Majorana neutrino mass, we find m ββ < (110 - 520) meV, where the range reflects the nuclear matrix element estimates employed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗