What is Positron: Definition and 115 Discussions

The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1 e, a spin of 1/2 (the same as the electron), and has the same mass as an electron. When a positron collides with an electron, annihilation occurs. If this collision occurs at low energies, it results in the production of two or more photons.
Positrons can be created by positron emission radioactive decay (through weak interactions), or by pair production from a sufficiently energetic photon which is interacting with an atom in a material.

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  1. V

    How do I write a nuclear equation for the annihilation of a positron?

    How do I write a nuclear equation representing the annihilation of a positron with an electron? Do they just cancel out? or do I write energy on the left hand side of the equation?
  2. W

    Positron movement in a coil-induced magnetic field

    in a microscopy class: problem is to illustrate the path of a positron on both sides of the axis in a coil produced magnetic field. consider both cases of the particle's velocity and the magnetic field being a)in the same direction & b)in opposite directions. i have no clue. any help? would it...
  3. C

    Simple question about photons turning into electorn positron pairs.

    Homework Statement This is a really easy one, goodness only knows why I can't think of how to do it, here goes " Explain why a photon in free space cannot turn into an electron-positron pair." Homework Equations I assume E^2- P^2 = 0 will be of some help The Attempt at a...
  4. U

    Electric fields of electron and positron that undergo pair annihilation.

    Here is a question, which may seem dumb: Consider an electron and a positron that annihilate, both of which are non-relativistic (taking the observer's frame of reference to be the center of mass frame of the electron-positron pair) so that we only consider their electric fields for simplicity...
  5. T

    Positron - electron annihilation

    Homework Statement A positron having a kinetic energy equal to its rest mass energy mec^2 collides with a stationary electron. The positron and the electron annihilate in the process and two photons are created. What is the maximum possible energy of a photon produced in the...
  6. P

    Electron and positron annihilation

    Problem:An electron flies toward +x direction with velocity of 0.9c, while a positron flies toward -y direction with the same velocity. Assuming their speed is so fast that they collide and annihilate at the origin, what will be the magnitude and the direction of the wave vector of the generated...
  7. F

    Positron creation in semiconductors?

    I've posted a similar question to the high energy forum. As I understand it, LEDs emit photons when electrons and holes have sufficient energy to cross a particular "well". I'm sure this explanation is lacking in many key ways. Why can't we "tune" the gap to create electron-positron pairs and...
  8. J

    What is the required energy for positron emission?

    In positron emission, a proton is converted into a neutron, a positron, and a neutrino: p --> n + e + v this conversion occures only in a nucleus, because this process consumes energy (the neutron and positron have a higher mass than the proton). The energy needed is twice...
  9. K

    Positron Theory Explained: Electric Neutral Atoms

    In sense of the Dirac hole theory the space must have a charge that is infiniti positive. Why do then electric neutral atoms exist?
  10. P

    Electron vs. positron? / spin?

    Hi all, (1) What is the difference between electron & positron? I know that they have opposite charges, but what does that deeply mean? Someone told me that the different sign of the charge is related to the spin: Electron is said to have spin up if it is spinning CCW, but the positron...
  11. L

    Exploring the Electron, Neutrino & Positron

    the electron, neutrino and positron as well? Hope I'm asking this at the right place, and that my spelling was ok! Thanks for any replies! Linda, Sweden
  12. M

    Production of massive neutrinos in electron - positron annihilation.

    I bumbed in such event in on book written in middle 80's. Does anyone know anything of such phenomena? Has that theory been killed or is there any info available of it anywhere?? Oh joy... I'm writing an essay of neutrinos, and I am really lost.. :| Oh, and another question... Any other...
  13. arivero

    Beta or positron induced reactions?

    Looking at the table of isotopic masses table it seems that certain atoms, as 64Zn or 58Ni, could be able to capture an electron and then release a positron with an energy higher, in average, that the initial electron. On the other side, some nucleus are able to capture a positron and release...
  14. J

    Positron in a magnetic field help

    some more basic homework help! can you guys point me in the right direction, where to start? (grrr, so freakin lost in this class) 11. A 22.5-eV positron (positively charged electron) is projected into a uniform magnetic field B = 455[mu]T with its velocity vector making an angle of 65.5...
  15. wolram

    Why doesn't the electron radiate its energy away and collapse into the nucleus?

    im out of my depth with this question so forgive me if it is stupid. it is stated that the electron borrows energy from "vacuum energy", as the eletron, positron are point particles i was thinking that they could be a, real world manifestation of the hidden world of vacuum energy. best wishes.
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