The concept of a color charge resolves the conundrum of quarks apparently having the same state in baryons which is no permitted by the Pauli Exclusion Principle.
In 1956 Ms. Chien Shiung Wu demonstrated that the weak nuclear force caused reactions of antimatter particles with quantum spin in only one direction and matter particles in the other direction. This was a tremendous shock to the physics community as the other forces don't care about quantum spin. Sadly the Nobel Prize for this discovery did not recognize Ms. Wu.
The weak nuclear force causes changes in the flavor of leptons; quarks, neutrinos and the electron family. But only the electrically charged W bosons, that are the forces carriers of the weak force, have been found to cause flavor changes. The Z bosons have not and physicists wonder why not.
In beta decay a neutron releases a W boson, the charge carrier of the weak nuclear force, to become a proton. But this only occurs if the W boson has a very low mass compared to it's 'normal' mass which is highly improbable. So the weak force appears weak. In contrast the Top quark has a mass larger than the W boson so it decays to a bottom quark almost instantly and the weak force appears strong relative to the other fundamental forces.
Sterile particles do not respond to the weak nuclear force. This comes into play with neutrinos because all neutrinos physicists have ever seen have a quantum spin arbitrarily referred to as left and respond to the week force. But right spinning neutrinos might exist if they are sterile.
Don notes that many of the comments he receives questioning the big bang often reflect a misunderstanding of the theory rather than a logical argument to refute it. So to give the skeptics a better foundation on which to mount their challenges he tries to dispel the misconceptions.
There are three general ideas about how the universe came to be. First, our universe existed in static form then began expanding. Second, static universes collided causing our universe to expand. Third, universes are created by splitting off from existing universes.
Scientists have no theory to identify what happened before the Big Bang, at the moment of the Big Bang or even before the Planck Time. There are plenty of ideas, and knowing quantum theory as we do, the reality could be terribly strange to us, but it's all informed speculation at this point.
Here's the story of the discovery of neutrino oscillation beginning with Ray Davis's phenomenon of the missing Solar neutrinos. Later, scientists at the Sudbury Neutrino Observatory figured out how to measure all the neutrinos types produced by the sun and their results matched both theory and Ray Davis's results for electron neutrinos.
Here are the answers to some viewer questions about neutrinos. In addition to the composition of custard here are some of bigger revelations. The is a cosmic neutrino background from one second after the big bang that scientists would love to be able to detect. Neutrinos can be destroyed. Neutrinos may be their own antiparticle.
If the double slit experiment confused you take a minute to review it because It's about to get lots more complicated and we're going to mess with time. After the photons pass through the slits let's split them into two beams so we can use two set of detectors. And you can turn on or off one set of detectors to change the behavior of the light from a particle to a wave before the photon know which they're supposed to be.
Kristy and Anne explain Fermilab's Numi Off-Axis Neutrino (V) Appearance 'NOVA' experiment. It consists of a beam of electron neutrinos and a near detector which counts the neutrinos and a far detector that detects mostly muon neutrinos because it is placed at a distance where oscillations are expected to have occurred.
Neutrinos travel as close as we can measure to the speed of light. But as they travel they changes flavor which takes time. So they are thought to travel slower that light if only slightly.
So far none of the particles that are their own antiparticle, like the photon, have mass. But that assumption has not been tested for the neutrino because it's really hard to determine. The extremely rare reaction of neutrinoless double beta decay could answer the question if enough of there reactions can be observed.
