1
$\begingroup$

Hopefully this one'll be a fairly easy answer. My understanding of pair production is that it is a simple transfer of momentum/energy in which an incident particle looses energy after a scattering interaction with a nucleus (or other more massive (?) particle) and that this energy is converted to a particle/antiparticle pair. Pretty much all of the sources that I've consulted (Introduction to Elementary Particles by Griffith, Mando & Ronchi 1952, etc.) talk about pair production of electrons, muons, and perhaps pions, (~ 0.5, 105, and 137 MeV/$c^2$ in mass respectively); but I've only found a very limited number of sources that mention higher energy pair production.

My basic question is whether it's theoretically possible for any particle/anti-particle pair (e.g. $D\overline{D}$ meson pair production) to be produced by a collision of sufficient energy within the constraint that all conserved quantum numbers must sum to 0? Or is there some upper limit imposed by theory? Obviously there is a practical upper limit, based upon the maximum energy of incident particle radiation observed in nature, or generated in a particle accelerator, but is there a theoretical upper limit to the particle mass of pair production?

Thanks! -D. Hodge

$\endgroup$
1
$\begingroup$

but I've only found a very limited number of sources that mention higher energy pair production.

Well, we do get antiproton beams, and those are produced in scattering off nucleons with enough energy so that the particle pair can appear.

The limit to pair production is the limit of the energy available . When the masses become large, the probability of producing them in pairs is small, but here is an experimental study for W+ W- production at LHC, testing the predictions of the theory. And a discussion of the even more massive top anti top creation, which from conservation of topness have to be generated in particle antiparticle pairs.

So yes, only the available energy limits the pairs that can be produced in pair production. At that level, that they are pair produced is a small part of the study of the processes which are examined for fitting or not fitting the standard model calculations, so not many experiments can have the accuracy to do so. That is why there is not much in literature, except for specific studies.

$\endgroup$
1
$\begingroup$

If energy and momentum are conserved, yes. For example from a collision of an electron and a positron with sufficient energy any particle/antiparticle pair can be created in principle.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.