# Electron-positron collisions

• noon0788
In summary: The probability that only a proton and an antiproton is produced is close to 0 since they consists together of 3 valance quarks and of equal flavour.
noon0788
I'm trying to understand electron-positron collisions and I've got a few questions if you don't mind :)

I know hadrons can be created through electron-positron annihilation. Can protons be produced like this? Has it been done before? How much energy would be required? How do you figure the amount of energy needed?

Also, does annihilation occur due to scattering? I think I'm confused on that terminology.

Thanks!

I know, but I can't find any information on if it's been done before.

noon0788 said:
I know, but I can't find any information on if it's been done before.

in high e+e- collisions one produces quark- antiquark pais, which hadronizes. The probability that only a proton and an antiproton is produced is close to 0 since they consists together of 3 valance quarks and of equal flavour.

noon0788 said:
I know, but I can't find any information on if it's been done before.

Yes, protons are among the measured products in high energy electron-positron collisions. An internet search shows, for example, the DELPHI experiment at LEP that among other things measured identified hadrons (including protons):

http://delphiwww.cern.ch/

The leading factor in the cross section for electron-positron (pair) production by photons (electromagnetic) is

σ0 = (1/137) (e2/mec2)2 = 0.58 x 10-27 cm2 = 0.58 millibarns

where me is the electron mass, so by substuting the proton mass Mp, the cross section for pbar-p (proton anti-proton) production in electron positron collisions is probably down by 18362, so

σ0 = ~2 x 10-34 cm2 = 200 picobarns for pbar-p production,

at collision energies well above 2 GeV (threshold to produce one p and one p-bar) in the center of mass. Equation 37.3 in

http://pdg.lbl.gov/2002/kinemarpp.pdf

gives the transformation from the energy in the lab frame to the energy in the center of mass frame.

Bob S

[added] The above very crude pbar-p production cross section estimate is probably missing an extra factor of 1/137. Also see page 10 of

http://moriond.in2p3.fr/QCD/2003/monday/Lin.pdf

for differential pbar-p cross section yields (units in picobarns) in the L3 CERN-LEP experiment.

Last edited:
what is position of the electron in the both magnetic field and elect. fild will be parellel ?

## What are electron-positron collisions?

Electron-positron collisions are a type of high-energy particle collision that takes place when an electron and a positron (the antimatter counterpart of an electron) collide with each other. This type of collision is commonly studied in particle physics experiments to understand the fundamental properties of matter and antimatter.

## How are electron-positron collisions created?

Electron-positron collisions can be created in a particle accelerator, such as the Large Hadron Collider (LHC). In these accelerators, electrons and positrons are accelerated to nearly the speed of light and then directed to collide with each other in a controlled environment.

## What happens during an electron-positron collision?

When an electron and a positron collide, they annihilate each other and produce energy in the form of gamma rays. This energy then converts into other particles, such as quarks, gluons, and other types of elementary particles. These collisions are essential in studying the properties of these particles and their interactions.

## Why are electron-positron collisions important in particle physics?

Electron-positron collisions allow scientists to study the fundamental properties of matter and antimatter, such as their mass, charge, and spin. They also provide insights into the behavior of particles at high energies and help verify the predictions of various theoretical models in particle physics.

## What are the potential applications of electron-positron collisions?

Electron-positron collisions have various potential applications, such as in the development of new medical treatments, such as positron emission tomography (PET) scans. They can also be used to create new types of materials with unique properties, such as antimatter-based electronics and energy sources.

• High Energy, Nuclear, Particle Physics
Replies
8
Views
1K
• High Energy, Nuclear, Particle Physics
Replies
9
Views
1K
• High Energy, Nuclear, Particle Physics
Replies
14
Views
3K
• High Energy, Nuclear, Particle Physics
Replies
17
Views
2K
• High Energy, Nuclear, Particle Physics
Replies
4
Views
2K
• High Energy, Nuclear, Particle Physics
Replies
6
Views
1K
• High Energy, Nuclear, Particle Physics
Replies
7
Views
2K
• High Energy, Nuclear, Particle Physics
Replies
53
Views
9K
• High Energy, Nuclear, Particle Physics
Replies
8
Views
1K
• High Energy, Nuclear, Particle Physics
Replies
3
Views
2K