Positron Definition and 113 Threads

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...

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...

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...

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...

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...

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...

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

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...

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

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...

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...

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...

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.