# Anti neutrino

1. Mar 5, 2006

### En_lizard

i heard that neutrino isn't made of quarks, it almost has no mass but it has a anti matter. what is the difference between a neutrino and its anti particle? what parity is?

2. Mar 5, 2006

### Staff: Mentor

When a neutrino interacts, it produces a neutrino or a negatively-charged lepton: e-, mu- or tau- depending on the "flavor" of the neutrino. For example,

$$\nu_e + n \rightarrow e^- + p$$

When an antineutrino interacts, it produces an antineutrino or a positively-charged lepton: e+, mu+ or tau+. For example,

$${\overline{\nu}}_e + p \rightarrow e^+ + n$$

Last edited: Mar 5, 2006
3. Mar 5, 2006

### ZapperZ

Staff Emeritus
You seem to be missing the bigger picture here.

Anti-neutrino is a lepton. Lepton is a family that includes electrons, muons, taus, their neutrinos, and their anti-neutrinos. NONE of them are made up of quarks!

Zz.

4. Mar 13, 2006

### En_lizard

thanks jtbell!

i guess theres no answer for my question and they just know about anti mattters from reactions.

5. Mar 13, 2006

### En_lizard

another one:
do we need to spend energy for making antimatter? and i heard that antimatter is the most powerful energy source to man? how it increases energy?

6. Mar 14, 2006

### AlphaNumeric

Antimatter is a classification for particles which have the opposite quantum numbers (like charge, lepton number, baryon number etc) to particles we commonly found in real life (electrons, protons etc).

For instance jtbell's reaction shows an electron and a neutrino being produced. We call that neutrino an 'antineutrino' because it needs to have a negative lepton number to cancel the positive lepton number the electron has because the proton originally had no lepton number and you have to conserve lepton numbers.

Antimatter was predicted by Dirac before it was observed. It arose from his development of quantum field theory (though initially his exact interpretation was different from the modern view, energy holes in the vacuum state).
Yes, antimatter isn't naturally occuring in large amounts. Pretty sophisticated machinery is needed to make antimatter, and you have to actually turn energy into the antimatter. It's like saying hydrogen fuel cells are an excellent power source. They are a storage method, because you make the hydrogen from methane or using electricity to split water. Antimatter has the largest useful energy density you could possibly have because you can use $$E=mc^{2}$$ to get all the energy locked up in it's mass. Petrol uses chemical energy, and losses only a tiny fraction of a percent of it's mass when you burn it.

It'd be good for spacecraft but only because you'd need a tiny amount of fuel, unless the thousands of tons needed at the moment. You'd still need to make the antimatter from some other power source.

7. Mar 14, 2006

### ZapperZ

Staff Emeritus
No, my response was more in curiosity on why you "picked" on just neutrino specifically. If it's a criteria that it isn't made up of quarks, then you left out a bunch of other particles. If it's a criteria based on "no mass and no quark", then photons get left out.

So my querry was more on whether your question was a more general question on a family of things, or simply on neutrinos in particular. And ironically, a workshop on the next possible large neutrino project is going on right across the hall from my office. They're discussing the physics and feasibility of the Double Chooz experiment.

http://www.hep.anl.gov/dchooz/

Zz.

8. Mar 19, 2006

### En_lizard

thanx folks!

do we have anti photons?

9. Mar 19, 2006

### ZapperZ

Staff Emeritus
Obviously, you chose to not answer my querry. Oh well.....

Zz.

10. Mar 9, 2007

### En_lizard

i'd answered ur question. i didnt and still don't know if photon has anti particle, so that's the reason i picked up neutrino since it's the only chargeless massless particle with anti particle. but it seems it's you who choose to not answer me.

11. Mar 9, 2007

### Parlyne

Photons are their own antiparticle; and, neutrinos are not massless.