This is the obstacle the international KArlsruhe TRItium Neutrino (KATRIN) experiment at Karlsruhe Institute of Technology (KIT) with partners from 6 countries has used up as the world ´ s most sensitive scale for neutrinos. It makes usage of the beta decay of tritium, an unstable hydrogen isotope, to determine the mass of the neutrino by means of the energy distribution of electrons released in the decay process. This necessitates a significant technological effort: the 70 meter long experiment homes the world ´ s most intense tritium source along with a giant spectrometer to measure the energy of decay electrons with extraordinary accuracy.
Installing of electrodes in the main spectrometer of the KATRIN experiment. Credit: Joachim Wolf/KIT
The high quality of the information after starting clinical measurements in 2019 has actually continuously been enhanced over the last two years. “KATRIN is an experiment with the greatest technological requirements and is now running like best clockwork” enthuses Guido Drexlin (KIT), the project leader and among the two co-spokespersons of the experiment. Christian Weinheimer (University of Münster), the other co-spokesperson, includes that “the increase of the signal rate and the reduction of background rate were decisive for the brand-new outcome.”
Data analysis
The extensive analysis of this data was demanding everything from the global analysis team led by its two coordinators, Susanne Mertens (Max Planck Institute for Physics and TU Munich) and Magnus Schlösser (KIT). We are especially proud of our analysis team which successfully took up this substantial difficulty with fantastic dedication,” the 2 analysis coordinators are pleased to report.
The 70 meter long KATRIN try out its primary components tritium source, primary spectrometer and detector. Credit: Leonard Köllenberger/ KATRIN Collaboration
The speculative data from the first year of measurements and the modeling based upon a vanishingly small neutrino mass match perfectly: from this, a brand-new ceiling on the neutrino mass of 0.8 eV can be determined (Nature Physics, July 2021). This is the very first time that a direct neutrino mass experiment has actually gone into the cosmologically and particle-physically important sub-eV mass variety, where the basic mass scale of neutrinos is thought to be. “The particle physics community is delighted that the 1-eV-barrier has actually been broken by KATRIN,” comments neutrino expert John Wilkerson (University of North Carolina, Chair of the Executive Board).
Susanne Mertens discusses the path to the new record: “Our team at the MPP in Munich has actually developed a new analysis method for KATRIN that is specifically optimized for the requirements of this high-precision measurement. This strategy has actually been effectively used for previous and current results. My group is extremely encouraged: We will continue to satisfy the future difficulties of KATRIN analysis with brand-new imaginative ideas and precise accuracy.”
Reference: “Direct neutrino-mass measurement with sub-eV sensitivity” 14 February 2022, Nature Physics.DOI: 10.1038/ s41567-021-01463-1.
More measurements ought to improve sensitivity
The co-spokespersons and analysis organizers of KATRIN are very optimistic about the future: “Further measurements of the neutrino mass will continue until completion of 2024. To recognize the full capacity of this distinct experiment, we will not just steadily increase the statistics of signal occasions, we are constantly developing and setting up enhancements to further reduce the background rate.”
The development of a new detector system (TRISTAN) plays a particular function in this, permitting KATRIN from 2025 on to embark on a look for “sterile” neutrinos with masses in the kiloelectronvolt-range, a candidate for the strange dark matter in the cosmos that has actually already manifested itself in lots of astrophysical and cosmological observations, however whose particle-physical nature is still unknown.
Neutrinos Are Lighter Than 0.8 Electronvolts
Brand-new world record: KATRIN experiment restricts neutrino mass with unprecedented accuracy.
Neutrinos are arguably the most fascinating primary particle in our universe. In cosmology they play an important function in the formation of massive structures, while in particle physics their small but non-zero mass sets them apart, pointing to new physics phenomena beyond our existing theories. Without a measurement of the mass scale of neutrinos, our understanding of the universe will remain insufficient.
It makes use of the beta decay of tritium, an unstable hydrogen isotope, to figure out the mass of the neutrino via the energy circulation of electrons released in the decay process. The speculative information from the very first year of measurements and the modeling based on a vanishingly small neutrino mass match perfectly: from this, a new upper limitation on the neutrino mass of 0.8 eV can be figured out (Nature Physics, July 2021). This is the very first time that a direct neutrino mass experiment has actually gone into the cosmologically and particle-physically important sub-eV mass variety, where the fundamental mass scale of neutrinos is thought to be. “The particle physics community is delighted that the 1-eV-barrier has actually been broken by KATRIN,” comments neutrino expert John Wilkerson (University of North Carolina, Chair of the Executive Board).
Scientists typically refer to the neutrino as the” ghost particle” since they almost never interact with other matter.
Without a measurement of the mass scale of neutrinos, our understanding of the universe will stay insufficient.
