Neutrino property

[Jacques]

Tell me if I am right but neutrino were invented to account for some energy that does showup in nuclear fusion: conting the mass and energy before the fusion and the mass and energy after, there was a discrepancy. So the neutrino was born.

Neutrino carry energy.

Does neutrino have momentum ?

Does netrino have spin ?

I know they don't have electric charge and I suppose that they don't have magnetic charge because they would interact with matter.

There is some evidence that they have mass. So they must have momentum ...

If they have mass they are not moving at the speed of light.

Also the detectors all around the world detect a so small number of events out of false event caused by natural radioactivity cosmic-ray etc... How much confidence can we put in these mesurement. Can we say we are 100% sure that these mesurement are from neutrino events or must we say that there is a good probability...

These particle fascinate me and I would like to know more about them.

Thanks

[[Tycho?]]

http://www.wikipedia.org

 

Even massless particles have momentum, so neutrinos do as well.

[5614]

Neutrinos:

 

Have a small mass, but the fact that they have a mass does mean they travel slower than light.

 

They have momentum.

 

It is a 1/2 spin particle.

 

There are 3 types, electron, muon & tau neutrino (and obviously each has their own anti particle)

 

The neutrino only interacts via the weak and gravitational forces, so it hardly interacts with matter, indeed one of my old sigs was:

"it would take approximately one light year (~10^16m) of lead to block half number of neutrinos"

demonstrates how little neutrinos interact with matter.

 

Why do these particles in particular interest you?

Any more specific questions?

 

See here:

http://en.wikipedia.org/wiki/Neutrino

http://hyperphysics.phy-astr.gsu.edu/hbase/particles/neutrino.html

http://scienceworld.wolfram.com/physics/Neutrino.html

http://www.colorado.edu/physics/2000/isotopes/neutrino.html

[swansont]

The neutrino was actually hypothesized when it was observed that beta decay appeared to conserve neither linear nor angular momentum, nor energy. From that information one can actually start to predict the properties it should have.

[BhavinB]

The neutrino was actually hypothesized when it was observed that beta decay appeared to conserve neither linear nor angular momentum, nor energy. From that information one can actually start to predict the properties it should have.

 

I remember a physics lab topic was to determine the properties of the neutrino using beta decay. One of the properties I had to find was the mass of a neutrino...lol. Interestingly, that was around the time when scientists started believing neutrino's might be massless.

[Severian]

The observation that neutrinos have mass is relatively recent (the last decade) and there is now a lot of interest in determining their properties more precisely.

 

http://www.hep.ph.ic.ac.uk/iss/

[Jacques]

Have a small mass, but the fact that they have a mass does mean they travel slower than light.

Doesn't that violate relativity ?

[Royston]

Doesn't that violate relativity ?

 

It would if they travelled faster than light.

[Jacques]

I thaught that a mass traveling at the speed of light would have infinite energy ???

[swansont]

I thaught that a mass traveling at the speed of light would have infinite energy ???

 

Yes, the equation for E diverges in that case. Nobody here has proposed that neutrinos have mass and travel at c.

[Jacques]

Nobody here has proposed that neutrinos have mass and travel at c.

Look post #3 from 5416

[timo]

Nobody here has proposed that neutrinos have mass and travel at c.[/quote']Look post #3 from 5416

Can you quote the passage you mean, Jacques? I can´t find it.

[Jacques]

Have a small mass, but the fact that they have a mass does mean they travel slower than light.

Oups Sorry I misreaded

[Jacques]

Does the speed of neutrinos have been mesured ?

Does it mean that a neutrinos can exist at rest ?

 

From what I readed, Hydrogen, chloride and gallium are used in detectors.

Does these elements have some special property that increase the chance of a neutrino to interact with ?

[5614]

Neutrinos will react with protons, so using a H+ hydrogen ion (which is just a proton) provides a proton source. This interaction results (I'm fairly sure) in a muon and an antimuon being produced.

 

Neutrinos travel a little below the speed of light, I do not know an exact value to tell you, but it has most probably been measured.

 

Now I'm not sure about this, but I think that theoretically a neutrino could be at rest because, well, the only reason a particle cannot be at rest is in the case of a photon where it must always travel at c relative to the observer. The neutrino is under no such law, so why couldn't it be at rest?

[swansont]

Neutrino stuff from hyperphysics.

[Tom Mattson]

I know they don't have electric charge and I suppose that they don't have magnetic charge because they would interact with matter.

 

Neutrinos do interact with matter' date=' but they only do it via the weak interaction (I'm neglecting gravity because it doesn't fit into particle physics yet). That's why they are so difficult to detect.

 

There is some evidence that they have mass. So they must have momentum ...

 

That is true, but I just want to point out that the inverse isn't true. That is even if the neutrino did not have mass, it would still have a momentum.

[Jacques]

Yes I know I should have said, interact very little with matter.

 

Thanks for all your answers !