Muons result from cosmic rays, but cosmic rays are protons that decay?

In summary, protons decay into muons after colliding with matter on Earth. The proton itself does not decay, but the muons are the decay products of the high energy protons.
  • #1
AlexanderRios
7
0
I am wondering how Muons are manufactured.

Wikipedia says they're the decay products of cosmic rays, and that cosmic rays are usually high energy protons.

So a high energy proton (cosmic ray) decays into a muon after colliding with matter on earth.
How is consistent with the fact that protons are so-called 'stable particles'?

Doesn't 'stable' mean 'won't decay'?
 
Physics news on Phys.org
  • #2
AlexanderRios said:
So a high energy proton (cosmic ray) decays into a muon after colliding with matter on earth.

Not quite. A proton will collide with a nucleus in the upper atmosphere, creating many particles. Some of the created particles, for example charged pions, decay to muons. The proton itself does not decay.
 
  • Like
Likes 1 person
  • #3
decay means that if you have an isolated proton, then it will remain a proton. Decays are of the form [itex] A \rightarrow B+C + ... [/itex]. For example the protons in a nucleus can go through a beta+ decay.

What happens in the atmosphere is something similar to what happens in a pp collider... you have a proton colliding with the matter [other nuclei] in the atmosphere, and then several particles can come out of this, as for example the pions which give you the muons.
 
  • Like
Likes 1 person
  • #4
OK. So stable means won't decay if it doesn't collide with another particle?

Do protons that collide with other matter transmogrify into pions, and then the pions decay into muons?
Does the proton ever disappear or turn into something else?
 
  • #5
So protons can be decomposed by collisions. Right?

I mean a proton (UUD) can collide and break into a pion (U/D) and other stuff too. Is this true?
 
  • #6
'Decaying' is spontaneous decomposition?
 
  • #7
stable means that it doesn't decay if it's isolated... The collision is not a decay (you have at least two particles participating). As I wrote above, proton would decay if a process like the
[itex] p \rightarrow [stuff] [/itex]
was to happen. There is no such process. What is happening is the hard scattering of protons to neutrons or protons in the atmosphere. The result can be a lot of things, but most of these end up in pions, neutrons and protons. The charged pions then can decay with weak interactions and give muons. And this ends up creating a shower of particles in the upper atmosphere.
http://www.hawc-observatory.org/img/cosmic_interactions.gif

The proton can remain a proton or it can become something else.
 
  • Like
Likes 1 person
  • #8
AlexanderRios said:
OK. So stable means won't decay if it doesn't collide with another particle?
It does not decay at all.
A collision process is not called "decay".

Do protons that collide with other matter transmogrify into pions, and then the pions decay into muons?
No, those pions are newly created particles. They get produced together with various other particles. The charged particles decay to muons (and a neutrino).

Often the proton completely breaks up, it is not meaningful to ask "what does the proton gets transformed to".
 
  • Like
Likes 1 person
  • #9
mfb said:
Often the proton completely breaks up, it is not meaningful to ask "what does the proton gets transformed to".
Baryon number is conserved. So when the collision produces one or more antibaryons, it is not meaningful to ask which of the two or more baryons left is the original proton.

However, if the collision produces just leptons, mesons and various bosons then there will be just one baryon afterwards, and if not a proton then it is what the proton has been transformed to.
 

1. What are muons and how do they relate to cosmic rays?

Muons are subatomic particles that are similar to electrons, but with a much greater mass. They are created when high-energy cosmic rays, which are mostly protons, collide with particles in Earth's atmosphere. These cosmic rays lose energy and decay, producing muons as a result.

2. How are cosmic rays able to decay into muons?

Cosmic rays are composed of high-energy particles, mostly protons, that are constantly bombarding Earth from outer space. When these particles collide with atoms in Earth's atmosphere, they lose energy and decay into subatomic particles like muons.

3. Are muons the only particles created from cosmic ray decay?

No, muons are not the only particles created from cosmic ray decay. Other subatomic particles, such as pions and kaons, are also produced in this process. However, muons are the most abundant and longest-lived particles created from cosmic ray decay.

4. How do we know that muons are a result of cosmic ray decay?

Scientists have conducted experiments and observations that demonstrate the connection between cosmic rays and the production of muons. For example, studies have shown that the rate of muon production decreases at higher altitudes, where there are fewer cosmic rays present.

5. What is the significance of studying muons and cosmic rays?

The study of muons and cosmic rays can provide valuable information about high-energy particles and their interactions with matter. This research can also help us better understand the origins of cosmic rays and their potential impact on Earth's atmosphere and environment.

Similar threads

  • High Energy, Nuclear, Particle Physics
Replies
17
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
10
Views
695
  • High Energy, Nuclear, Particle Physics
Replies
2
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
3
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
  • Astronomy and Astrophysics
Replies
4
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
4
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
7
Views
954
  • High Energy, Nuclear, Particle Physics
Replies
15
Views
2K
  • High Energy, Nuclear, Particle Physics
2
Replies
43
Views
4K
Back
Top