Neutrinos

[steve_bank]

I watched a NOVA show on neutrinos. I don’t know a lot abouy partticle physics, it was a good overview for me. It showed ‘the method’. Going back and forth between experiment abd theory. Over time.

What stood out was the single minded focus over a lifetime of a handful of people. I had a hard time staying focused on a 6 month project.

The initial experiment to detect solar neutrinos measured 1/3 of the expected theoretical numbers. It brought a number of things into question including relativity.

An early idea to detect neutrinos was to bury a detector under a nuclear explosion, it went to a planning stage. Rejectd because it ‘would not be repeatable’. The evolution of the detectors was creative. One detector used dry cleaning solvent in a tank.

Conclusions at the end, we really do not have a clue what is goind on, and the Standar Model falls short.


NOVA The Ghost Particle

https://www.pbs.org/wgbh/nova/neutrino/

The Solar Neutrino Problem


https://en.wikipedia.org/wiki/Solar_neutrino_problem

The solar neutrino problem concerned a large discrepancy between the flux of solar neutrinos as predicted from the Sun's luminosity and as measured directly. The discrepancy was first observed in the mid-1960s and was resolved around 2002.

The flux of neutrinos at Earth is several tens of billions per square centimetre per second, mostly from the Sun's core. They are nevertheless hard to detect, because they interact very weakly with matter, traversing the whole Earth as light does a thin layer of air. Of the three types (flavors) of neutrinos known in the Standard Model of particle physics, the Sun produces only electron neutrinos. When neutrino detectors became sensitive enough to measure the flow of electron neutrinos from the Sun, the number detected was much lower than predicted. In various experiments, the number deficit was between one half and two thirds.

Particle physicists knew that a mechanism, discussed back in 1957 by Bruno Pontecorvo, could explain the deficit in electron neutrinos.[citation needed] However, they hesitated to accept it for various reasons, including the fact that it required a modification of the accepted Standard Model. They first pointed at the solar model for adjustment, which was ruled out. Today it is accepted that the neutrinos produced in the Sun are not massless particles as predicted by the Standard Model but rather mixed quantum states made up of defined-mass eigenstates in different (complex) proportions. That allows a neutrino produced as a pure electron neutrino to change during propagation into a mixture of electron, muon and tau neutrinos, with a reduced probability of being detected by a detector sensitive to only electron neutrinos.


Several neutrino detectors aiming at different flavors, energies, and traveled distance contributed to our present knowledge of neutrinos. In 2002 and 2015, a total of four researchers related to some of these detectors were awarded the Nobel Prize in Physics.

https://warwick.ac.uk/fac/sci/physi...inolectures/lec_neutrinodetectors_writeup.pdf


https://www.nature.com/articles/d41586-019-03874-w

https://en.wikipedia.org/wiki/Neutrino_detector

 

[Politesse]

I tried to get into neutrinos, but they just went right through me.

 

[bilby]

I read an article on neutrinos, but as far as I could tell, it was nothing but spin.