Pair production Definition and 110 Threads

Hi All :smile:, I have a question which is at least partly one of believe but I would be interested in your opinion. We know that there is some problem with the black hole's entropie. If some object with entropy S collapses and it evaporates completely via Hawking Radiation, then where has...

In pair production, an nucleus is needed to take away some momentum from the photon so momentum conservation is respected. correct?

How can a photon knock an electron from a shell, entirely out of the atom? (i.e PhotoElectric Effect) Photons have 0 rest mass, and little relativistic mass? For force, F = ma For example, let m = negligable (like the photon's mass is) mass so = mn If F = (mn)a and mn is small...

Is there a short answer why pair production can not happen in empty space, but that photons must interact with an external field? thanks and a nice weekend oh, just saw someone asked the same question in the nuclei section today and answers already there

if you want to show or prove that pair production cannot occur in empty space, why do you have to use the relativity equation?

Hi, I have heard someplace in my graduation course that two gamma photons are not allowed to yield a pair of particle anti-particle unless there is some material agent nearby. I remember also that this result was told to be very easy to demonstrate. Unfortunatelly there is no room for that in...

hi, this is about particle antiparticle pairs being produced outside the event horizon of black hole. this is what i know about it: we know that a black hole has entropy. it therefore must have temperature and hence must radiate. however, a black hole is defined as a body which pulls in...

Hi. Can pair production happen in vacuum? I had this question for a test. And the answer is: no, it cannot because it would violate the conservation of momentum, since you can't have a momentum zero photon. But i seem to recall that pair production happen in space (?). Due to...

I'm pretty much okay with pair production but in the eqt we have that a photo gives an electron and a positron. If we do it the other way round we have an electron and a positron giving 2 photos in order to conserve momentum. Why do we not have 2 photos of energy for pair production ir order...

Problem: A photon of energy E strikes an electron at rest and undergoes pair production, producing a positron and another electron. photon + e- --------> e+ + e- + e- The two electrons and the positron move off with identical linear momentum in the direction of the initial photon. All...