beecee Posted March 27, 2018 Posted March 27, 2018 https://phys.org/news/2018-03-scientists-results-neutrino-mountain.html Scientists report first results from neutrino mountain experiment March 27, 2018 by Jennifer Chu, Massachusetts Institute of Technology This week, an international team of physicists, including researchers at MIT, is reporting the first results from an underground experiment designed to answer one of physics' most fundamental questions: Why is our universe made mostly of matter? According to theory, the Big Bang should have produced equal amounts of matter and antimatter—the latter consisting of "antiparticles" that are essentially mirror images of matter, only bearing charges opposite to those of protons, electrons, neutrons, and other particle counterparts. And yet, we live in a decidedly material universe, made mostly of galaxies, stars, planets, and everything we see around us—and very little antimatter. Read more at: https://phys.org/news/2018-03-scientists-results-neutrino-mountain.html#jCpextract: There is a possibility that the neutrino may be its own antiparticle, meaning that it may have the ability to transform between a matter and antimatter version of itself. Read more at: https://phys.org/news/2018-03-scientists-results-neutrino-mountain.html#jCp the paper: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.132501 First Results from CUORE: A Search for Lepton Number Violation via 0νββ Decay of 130Te ABSTRACT 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-number-violating process: 130Te neutrinoless double-beta decay. Examining a total TeO2 exposure of 86.3 kg yr, characterized by an effective energy resolution of (7.7±0.5) keV FWHM and a background in the region of interest of (0.014±0.002) counts/(keV kg yr), we find no evidence for neutrinoless double-beta decay. Including systematic uncertainties, we place a lower limit on the decay half-life of T0ν1/2(130Te)>1.3×1025 yr (90% C.L.); the median statistical sensitivity of this search is 7.0×1024 yr. Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find T0ν1/2(130Te)>1.5×1025 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 mββ<(110−520) meV, where the range reflects the nuclear matrix element estimates employed.
Recommended Posts