The usually commonsensical Sabine Hossenfelder admits that this one stumps physicists: Well-attested observations of neutrinos are not compatible with the Standard Model of our universe that most physicists accept. Much about neutrinos is weird and it does not appear to be an artifact of bungled experiments:
Neutrinos would need mass in order to mix but, Hossenfelder says, we don’t know how they get mass. Other elementary particles get mass from the Higgs boson, which couples a left-handed version of the particle with a right-handed one. But all neutrinos appear to be left-handed.
But that still isn’t the weirdest part. The weirdest part is what happened when physicists tried to run a lengthy experiment to fit all the data together for a coherent picture:
By 2005, researchers had got all the parameters correct except for one experiment which “did not make sense”: the Liquid Scintillator Neutrino Detector (1993–1998). Couldn’t it just be discounted? The trouble was, as Hossenfelder points out, “In particle physics, the discovery threshold is 5 sigma. The 3.8 sigma of the LSND anomaly wasn’t enough to get excited, but too much to just ignore.”
Well then the physicists tried again, starting in 2003 with a long running experiment with neutrinos at Fermilab called the MiniBooNE experiment (the Mini Booster Neutrino Experiment). It’s been running ever since because neutrinos interact only rarely.
Did all the new data erase the rogue findings?
Not at all. In 2018 MiniBooNE, which had accumulated more data, confirmed the findings from LSND. “Yes, you heard that right,” Hossenfelder reports. “They confirmed it with 4.7 σ, and the combined significance is 6 σ.” Not just 5 σ but 6.
News, “Some elements of our universe do not make scientific sense” at Mind Matters News (February 19, 2022)
Takehome: Theoretical physicist Sabine Hossenfelder walks us through the reasons that neutrinos, nearly massless particles with no charge, confound expectations.
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You may also wish to read: Philosopher: We can’t prove that we aren’t living in a simulation. David Chalmers looks at the issues, step by step, in an excerpt from his new book Reality+ and rules out proving that it is false. The question isn’t as simple as that, of course. We are not obliged to take something seriously because we cannot prove it isn’t true.