This thread got me looking at Neutrinos for the very first time. They

[Tanelorn]

This thread got me looking at Neutrinos for the very first time. They are the most recently discovered fundermental particles, the Tau Neutrino was first observed only 11 years ago in 2000.


The neutrino was first postulated in 1930 by Wolfgang Pauli to preserve the conservation of energy, conservation of momentum, and conservation of angular momentum (spin) in beta decay. This was done by adding an undetected particle that Pauli termed a "neutron" to the proton and electron already known to be products of beta decay:

n0 → p+ + e− + νe

He theorized that an undetected particle was carrying away the observed difference between the energy, momentum, and angular momentum of the initial and final particles.
The electron neutrino is said to be associated with the electron because in the above beta decay they are produced together.



Since Neutrinos interact very weakly with ordinary matter it appears that matter is being continually converted all the time through beta decay into something which no longer interacts with matter.

 

[bapowell]

Since Neutrinos interact very weakly with ordinary matter it appears that matter is being continually converted all the time into something which no longer interacts with matter.

Neutrinos still very much constitute "normal matter". And there isn't an out-of-equilibrium conversion of all non-neutrino matter to neutrino matter: weak interactions must conserve charge as well as lepton number.

 

[Tanelorn]

bapowel yes I mispoke, Neutinos are still normal matter.

My point was, if I understand the subject correctly, that Mass and Energy in stars seems to be continually being converted into neutrinos, particles which radiate thoughout the universe and no longer interact or play any significant role with baryonic matter. i.e. the mass and energy is permanently lost.

 

[bapowell]

no longer interact or play any further role with baryonic matter.

...until they hit a detector at SuperK. It's true that neutrinos are very weakly interacting, but they do still mix and mingle with baryonic matter on occasion. Also, they contribute to the stress-energy of the universe and so they gravitate.

 

[Tanelorn]

OK I assume then that the process cannot ever be reversed and neutrinos reassembled back into useful baryonic matter again? I guess that EM radiation is also similar in this regard.