Evidence for the existence of neutrinos.

[_Mayday_]

[SOLVED] Evidence for the existence of neutrinos.

[solved]

 

[HallsofIvy]

Two points: at the elementary particle level, there is no "conservation of energy". There is 'conservation of energy/mass'. As far as conservation of momentum is concerned, that was, in fact, the reason Fermi "postulated" the existence of neutrinos in 1930.

What do you think of as "evidence"? I would think in terms of experimental evidenence for the existence of neutrinos, first given in 1956 at the Savannah River Nuclear Power Plant. Indeed, there is now a "neutrino observatory" at Sudbury, England that regularly detects neutrinos in cosmic rays.

 

[_Mayday_]

I guess by evidence, I mean how would a scientist explain to someone who has never heard of neutrinos, and had only ever leaned about simpler atomic structure, how we know they are there. I have done some reading into a few experiments carried out but I am more interested in the theory, or in other words why someone would think that there had to be something else other than a beta emission and the recoil nucleus in the first place.

I'm not sure what you mean by "At the elementary particle level, there is no "conservation of energy". There is 'conservation of energy/mass'." could you please explain that a bit more.

Thanks for the response.

 

[Moridin]

I'm not sure what you mean by "At the elementary particle level, there is no "conservation of energy". There is 'conservation of energy/mass'." could you please explain that a bit more.

Einstein showed that mass and energy are two different manifestations of the same basic "thing", which is here called mass/energy. In nuclear reactions mass as defined in classical physics, can be transformed to energy (as defined in classical physics).

Trivially, you can think of mass as a "form" on energy.

 

[_Mayday_]

Einstein showed that mass and energy are two different manifestations of the same basic "thing", which is here called mass/energy. In nuclear reactions mass as defined in classical physics, can be transformed to energy (as defined in classical physics).

Trivially, you can think of mass as a "form" on energy.

Going a bit off topic here, is this why people would say that a photon is massless as it has no energy or infact could be said to be, so therefor is able to travel at the speed of light?

Ok back on topic, thank you very much, that has cleared that up.

Any other "evidence" would be most apreciated.

 

[dst]

Going a bit off topic here, is this why people would say that a photon is massless as it has no energy or infact could be said to be, so therefor is able to travel at the speed of light?

Ok back on topic, thank you very much, that has cleared that up.

Any other "evidence" would be most apreciated.

No, a photon has no such thing as 'invariant mass' (as in a "mass" that everyone will observe regardless of their own conditions - hence unchanging) which is why it's called 'massless'.

 

[_Mayday_]

Ah, ok thanks for clearing that up.Would I be correct in saying I have most the evidence then?

 

[dst]

I would have thought conservation of momentum is more than enough?