How are neutral pi mesons formed and what is their composition?

In summary: There is no free source that could teach you everything you need to know about pi mesons. However, there are many sources that could provide you with a good understanding of the structure and composition of pi mesons.
  • #1
Garlic
Gold Member
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Hello,
I understand the fact that pi mesons are superpositions of uubar and ddbar. But what happens if a decay only produces a single type of meson? I am not sure of this, but omega baryon decaying into xi-minus and a neutral pion seems to produce ddbar mesons, is it so that only a single type of meson gets formed and then it oscillates between uubar and ddbar because of the relatively same mass those two mesons have?
Imagine that I'm bombarding protons with neutral pi mesons, how would the feynman diagramm look like? When we make pions react with other matter is it so that we are "measuring" it, and therefore forcing it to be in a certain eigenstate?
As far as I've understood, the composition of neutral pions are uubar - ddbar / sqrt2 is so because of the sightly higher mass of down quarks. Why isn't there be two neutral pions that have different mass and different composition, so that, the one we know, the normal neutral pion is going to have smaller mass, and the other neutral pion is going to be heavier with this composition uubar + ddbar / sqrt2 ?
Thank you
 
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  • #2
Garlic said:
is it so that only a single type of meson gets formed and then it oscillates between uubar and ddbar because of the relatively same mass those two mesons have?
The pi0 is a single particle, it is not oscillating. It even has a small strange/antistrange contribution. The QCD production of the particle "makes sure" it is produced in the right state. For the production and decay process, it can be regarded as u/ubar or d/dbar combination, but it actually is always a superposition of those.
 
  • #3
Just to mention, the flavour combinations which are orthogonal to the pi0 are the eta mesons. These have masses which are different from the pi0.
 
  • #4
mfb said:
The pi0 is a single particle, it is not oscillating. It even has a small strange/antistrange contribution. The QCD production of the particle "makes sure" it is produced in the right state. For the production and decay process, it can be regarded as u/ubar or d/dbar combination, but it actually is always a superposition of those.

Could you please recommend me a source to read? I need to understand the structure of pi mesons better. (It needs to be a free pdf- I'm not near a library and I don't have a credit card)

Thank you
 

1. What are neutral pi mesons?

Neutral pi mesons, also known as pi-zero mesons, are subatomic particles that are composed of a quark and an antiquark. They are part of the meson family, which are particles made of a quark and an antiquark.

2. What is the significance of studying neutral pi mesons?

Neutral pi mesons are important to study because they play a crucial role in the strong nuclear force, which is responsible for holding atomic nuclei together. They also provide valuable insights into the fundamental interactions between subatomic particles.

3. How are neutral pi mesons created?

Neutral pi mesons are primarily produced through the decay of other particles, such as pions, in high-energy collisions. They can also be created in particle accelerators by colliding protons or other particles with a target material.

4. What properties do neutral pi mesons have?

Neutral pi mesons have a very short lifespan, with an average decay time of only 8.4 x 10^-17 seconds. They also have a mass of approximately 135 times that of an electron and a charge of zero. They can decay into two photons or two electrons and a positron.

5. What are the potential applications of neutral pi mesons?

The study of neutral pi mesons has led to important advancements in our understanding of the strong nuclear force and the structure of matter. Additionally, their short decay time makes them useful for medical applications, such as cancer treatment, as they can be used to generate high-energy gamma rays.

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