November 2, 2024

Ghost Particles: Neutrinos Challenge Everything We Know About Physics

Exceptionally unusual neutrino crashes with other particles of matter can only be detected with big detectors.Neutrino Oscillations and the Challenge to the Standard ModelSolar neutrinos brought another ground-breaking discovery: the three types of neutrinos known to date can transform into each other. The oscillations required a rest mass for neutrinos– a further indicator that new physics need to exist beyond the standard model.Measuring Neutrino Mass through Beta DecayKnowing the exact rest mass of the neutrino would for that reason be an open sesame into the unidentified world of new physics. Against this background, the Heidelberg outcome is a major step forward on the method to fixing the mystery of neutrino masses.Reference: “Direct high-precision Penning-trap measurement of the Q-value of the electron capture in 163Ho for the determination of the electron neutrino mass” 19 April 2024, Nature Physics.DOI: 10.1038/ s41567-024-02461-9.

In 1956, speculative proof of such neutrinos was finally obtained.The difficulty: neutrinos just engage with other particles of matter via the weak interaction that is also underlying the beta decay of an atomic nucleus. Very rare neutrino accidents with other particles of matter can only be found with substantial detectors.Neutrino Oscillations and the Challenge to the Standard ModelSolar neutrinos brought another ground-breaking discovery: the 3 types of neutrinos understood to date can transform into each other. The oscillations required a rest mass for neutrinos– a further sign that new physics need to exist beyond the basic model.Measuring Neutrino Mass through Beta DecayKnowing the precise rest mass of the neutrino would therefore be an open sesame into the unknown world of new physics. And what does this mean for the neutrino masses?KATRIN determined the most exact upper limitation to date of the neutrino mass by “weighing” at 0.8 electron volt per speed of light squared, which corresponds to an unthinkable 0.0000000000000000000000000000000000014 kilogram!This order of magnitude of 10– 36 corresponds roughly to the weight ratio between four raisins and the sun. Versus this background, the Heidelberg result is a significant step forward on the method to resolving the mystery of neutrino masses.Reference: “Direct high-precision Penning-trap measurement of the Q-value of the electron capture in 163Ho for the decision of the electron neutrino mass” 19 April 2024, Nature Physics.DOI: 10.1038/ s41567-024-02461-9.