# Muons and tauons

1. Mar 26, 2009

### dangerbird

does the sun make them?

Last edited: Mar 26, 2009
2. Mar 26, 2009

Staff Emeritus
There is no such thing as a "tauon". It's just a "tau", or "tau lepton". The sun does not make them, nor does it make muons.

3. Mar 27, 2009

### dangerbird

i was just reading this it says the sun makes pions which turn into muons. http://www.hps.org/publicinformation/ate/q3781.html [Broken]

whys there so much confusion about muons it doesnt make sense that a pion which is smaller than a muon can change into it as it goes through the earths atmosphere. is this another force?

i know im asking buckets of questions but im confused. answers are very much appreciated though

Last edited by a moderator: May 4, 2017
4. Mar 27, 2009

### Staff: Mentor

No, it doesn't say that. It says:

That is, the sun produces protons, which interact with nuclei in our atmosphere to produce pions (and other stuff). The pions in turn (mostly) decay into muons plus neutrinos.

Are you referring to their masses?

Mass of a muon: 105.6 MeV/c^2

Mass of a (charged) pion: 139.6 MeV/c^2

Last edited by a moderator: May 4, 2017
5. Mar 27, 2009

### dangerbird

so the pions come from space and as they enter the atmosphere decay to a muon correct which is lighter... right? and this is the only place where muons come from right? im just making sure im learning this right i dont have a book

6. Mar 27, 2009

### Staff: Mentor

No, the protons come from space. When they enter the atmosphere, they collide with nuclei of atoms in the atmosphere, producing mostly pions.

The pions decay into muons because muons are lighter, and this particular decay isn't otherwise forbidden or suppressed.

We generally produce muons via pion decay, if that's what you mean. We can do it at accelerator laboratories, too. For example, at Fermilab (which is a proton accelerator), they take a beam of protons and smack it into a metal target, producing lots of different kinds of particles, mostly pions (just like the protons coming from the sun when they collide with nuclei in the atmosphere). The pions decay into muons.

7. Mar 27, 2009

### dangerbird

good that clears up the confusing and seemingly conflicting stuff. the protons come from the solar wind and other star's then huh.

8. Mar 27, 2009

### Astronuc

Staff Emeritus
Young stars are mostly hydrogen. Helium (He-4) is a product of fusion. There are conditions when He fusion occurs, and the fusion of heavier elements.

The sun and most stars are mostly hydrogen, and some hydrogen (with electrons) leaves to produce the solar wind.

http://csep10.phys.utk.edu/astr162/lect/energy/ppchain.html

High energy protons originate from supernovae and other exotic objects
http://www2.slac.stanford.edu/vvc/cosmicrays/
http://www2.slac.stanford.edu/vvc/cosmicrays/cratmos.html

http://www-pdg.lbl.gov/2008/reviews/rpp2008-rev-cosmic-rays.pdf