Why particles in a bubble chamber seam to disappear?

In summary, the conversation discusses the role of antimatter particles in explaining the disappearance of tracks in bubble chambers. It is explained that when charged particles interact with their opposites, they form neutral particles that do not leave tracks. The conversation also mentions how antimatter can be contained and identified through its interactions and energy conversion. Additionally, the production of gamma rays and neutrinos in the annihilation process is discussed, as well as the direction and spectrum of the gamma rays. Finally, there is a mention of simulating pi0 decay in pp collisions and the role of intrinsic pi0 boost in producing the gamma spectrum.
  • #1
dangerbird
38
0
are antimatter particles the explanation for why particles in a bubble chamber seam to disappear? I've read some on antimatter and supposedly some of it's been contained, how do they know what they have is antimatter?

so many things theyre all confusing
 
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  • #2


If someone answers dangerbird's question can someone answer my question too?

When antimatter and matter react and turn into energy, is 100% of the mass energy of both antimatter and matter converted into energy? I heard somewhere that something is produced, a neutrino? I have been told that the energy released is in the form of radiation, a gamma ray. If so, is the gamma ray(s) emitted in all directions from the point of annihilation? If there are multiple gamma rays, wouldn't they be emitted at the same time? What would dictate the direction of the gamma ray(s)?
 
  • #3


The reason for why tracks in bubble chambers seem to disappear are many, if you provide an example of an reaction we can guide you.There is no such thing that *pure* energy, so there is always a conversion. When a particle and an antiparticle annihilate, it will create two photons if they annihilate via the electromagnetic force. The photons are sent back to back in the centre of mass system. The direction of the gamma rays in the lab-frame, in which we observe them, are decided by the relative initial motion of the particle and the antiparticle.

If there are two leptons, one lepton and one anti-lepton, they can annihilate via the weak force as well - creating two neutrinos via a virtual z_boson exchange.

Similar, two quarks, one quark and one anti-quark can annihilate into gluons etc. since they also have the strong interaction.
 
  • #4


Thank you very much for answering my question.
 
  • #5


dangerbird said:
are antimatter particles the explanation for why particles in a bubble chamber seam to disappear? I've read some on antimatter and supposedly some of it's been contained, how do they know what they have is antimatter?
Charged particles in bubble chambers leave tracks by virtue of ioniziation of the atoms of the saturated vapor in the bubble chamber. The disappearance of a track means that a charged particle has interacted with another charged particle of an opposite charge, e.g. a π- interacts with a proton p and forms neutral particle(s), e.g. Λo and Ko. Neutral particles do not leave tracks, but eventually most decay to charged particles, which do leave tracks.
 
  • #6


When antibaryons (e.g., anti proton) stop in a bubble chamber, it annihilates with a proton, and all of the energy is converted into pions, (plus, zero, and minus) the charged pions leave tracks ("star"), while the pi zero immediately usually decays into two 67 MeV photons. A stopping proton leaves only a dense track due to heavy ionization (Bragg peak).
 
  • #7


hmm I have simulated pi0 decay produced in pp collisions, and that gamma-spectrum is very continuous.
 
  • #8


malawi_glenn said:
hmm I have simulated pi0 decay produced in pp collisions, and that gamma-spectrum is very continuous.

It's strongly peaked in the pi0 rest frame, but they are 'never' at rest in a pp collision. I think you'll find it's the intrinsic pi0 boost which produces the spectrum.
 
  • #9


Yes of course it is the pi0 boost ;-)
 

Related to Why particles in a bubble chamber seam to disappear?

1. Why do particles in a bubble chamber seem to disappear?

Particles in a bubble chamber seem to disappear because they undergo a process called "energy loss". This occurs when the particles collide with the liquid in the chamber, causing them to slow down and lose energy. As a result, they may not be visible in the chamber for very long.

2. How does energy loss affect the visibility of particles in a bubble chamber?

Energy loss can affect the visibility of particles in a bubble chamber in two ways. First, it can cause the particles to slow down and eventually disappear from view. Second, it can create a shock wave that forms a bubble, which can obscure the view of the particles behind it.

3. Can particles reappear after disappearing in a bubble chamber?

Yes, particles can reappear after disappearing in a bubble chamber. This can happen if the particles gain enough energy from other particles or external sources, causing them to become visible again in the chamber.

4. Do all particles in a bubble chamber disappear?

No, not all particles in a bubble chamber will disappear. Some particles may have enough energy to continue moving and remain visible in the chamber, while others may dissipate or decay before disappearing.

5. How do scientists use bubble chambers to study particle physics?

Scientists use bubble chambers to study particle physics by observing the tracks of particles as they pass through the chamber. By analyzing the tracks, scientists can determine the properties and behaviors of different particles, which can help us better understand the fundamental building blocks of the universe.

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