1/13/2024 0 Comments Neutrino day 2019![]() From July 24 to August 1, over 800 cosmic ray physicists gathered at the Memorial Union on Lake Mendota to discuss the latest in cosmic ray research. Submitted to the European Physical Journal /abs/1902.The 36th International Cosmic Ray Conference finished up last week at the University of Wisconsin–Madison. Three Years of IceCube DeepCore Data,” The IceCube Collaboration: M. Info “Probing the Neutrino Mass Ordering with Atmospheric Neutrinos from “We have now proven that the concept of future extensions of IceCube do work in practice and thus we can look forward to unprecedented measurements of neutrino properties,” says Steven Wren, also a main analyzer of this study who worked on this analysis as a PhD candidate at the University of Manchester. It will deploy new sensors within DeepCore, which will greatly enhance the accuracy of detecting these lowest energy neutrinos in IceCube that are most critical for this measurement. The IceCube Upgrade is already underway and is expected to be completed by 2023. Another valuable outcome of this study is the successful implementation and verification of analysis methods that have been prototyped for future extensions of IceCube such as PINGU or the imminent IceCube Upgrade. Unlike beam experiments, this result is independent of the CP-violating phase, another important parameter for characterizing neutrino oscillations. Although the ordering signature is very weak, it provides a complimentary measurement. “When we embarked on this new analysis we were not aware of all the experimental challenges that we had to solve to measure the faint signals of these low-energy neutrinos with a sufficient precision,” says Martin Leuermann, a main analyzer of this study who worked on this analysis as a PhD candidate at RWTH Aachen University.īoth analyses obtain a consistent result within their uncertainties and a small preference for NO. In this study, researchers performed two independent analyses, both using three years of IceCube data and targeting this challenging measurement of the neutrino mass ordering with low-energy atmospheric neutrinos in IceCube. The high statistics of detected neutrinos within IceCube allows us to search for this small effect. Interestingly, this modulation depends on the mass ordering. For atmospheric neutrinos, the propagation through Earth induces a small modulation of the oscillation of neutrinos below 15 GeV, at about the lowest neutrino energies detected in IceCube. Several current and future long-baseline accelerator experiments, as well as experiments with atmospheric neutrinos and reactor neutrinos, are targeting a precise measurement of the mass ordering. Also depending on this mass ordering, the outcomes of a supernova explosion might be different. ![]() Some unification theories, for example, predict a normal mass ordering. ![]() These mass states are called neutrinos 1, 2 and 3.īut we know very little about neutrino mass, except that for all neutrinos it is very small and that nature may work fairly differently depending on which neutrino is more massive. those for which the mass is a well-defined property, are not the same as the neutrino flavor states, the states in which neutrinos interact. This quantum effect is explained by the fact that neutrino mass states, i.e. When neutrinos travel through space and matter, they oscillate, meaning they change their flavor (electron, muon or tau) depending on their energy and the propagation distance. The preference for NO over IO is visible over all the range of sin2 (θ23) with the best-fit for both orderings being in the lower octant (sin2 (θ23) < 0.5). The negative log-likelihood (LLH) as a function of sin2(θ23) for Analysis A, relative to the global minimum LLHmin. This paper has been submitted to the European Physical Journal. A weak preference is shown for NO, a result that is complementary to and in agreement with results from other experiments. Is the third neutrino more massive than the other neutrinos, in what scientists call the normal ordering (NO), or is it lighter, referred to as inverted ordering (IO)? In a new paper by the IceCube Collaboration, physicists use the inner and denser DeepCore detector within IceCube to try to answer this question. One of the main open questions in neutrino physics is the relative mass of the three neutrino types, a property known as the neutrino mass ordering. In particular, neutrinos themselves are the origin of still unresolved and maybe totally new physics. These intriguing particles may have the answer to a few, long-standing open questions in physics and astronomy. Neutrinos are used to investigate a broad spectrum of physics topics, ranging from the extreme universe to the underlying symmetries of nature.
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