Nuetrinos

[jezter]

If neutrinos do not interact with matter and cannot be effected by magnetic fields then how do we:
(a) Focus them into a beam to shoot from CERN to Gran Sasso?
(b) Detect them when they get there?
(c) Tell if they are are the ones from CERN?

Also if Neutrinos are flung out from a supernovae, how do we detect them as well? I mean arent there loads of these flying about?

[jake-the-peg]

They do interact with matter just very weakly.

To detect them you fill a whopping great swimming pool with water, line it with detectors and bury it

See Super-Kamiokande

[beso]

I don't think they are focussed in a beam.

They are know to be from CERN by the direction and the pulse.

Supernovae release enormous numbers of neutrinos. Once again they are known from the direction but also the increase in flux.

In fact the neutrinos from supernovae arrive here before the light. The light takes some time to escape the explosion but the neutrinos come straight out without interacting. It is quite handy for allowing the telescopes to be turned to the event before the light gets here.

[jake-the-peg]

Sorry was in a bit of a hurry - here's the paper and experiment description

http://arxiv.org/ftp/...rs/1109/1109.4897.pdf

You shoot Protons out of CERN and hit a target with them - you get a shower of pions and kaons out of that ( these are the most common output when protons collide) these are all shooting off in roughly the same direction as the original protons. Kaons decay to pions and pions decay to muons and muon neutrinos.

the muons are used to trigger the timer start and the nutrinos detected in Italy.

10^20 protons strikes during the course of the experiment resulted in only 16,111 neutrino detections.

As I said they react very weakly!