In a recent show in our country it was depicted that after collision of matter and antimatter electron and protons are created .It's a burning topic in our area now , and I couldn't find satisfiable answer through googling.. So is it possible ?


No, it is not possible. That would violate the conservation of lepton and baryon number.

  • $\begingroup$ I'd agree, with the caveat that colliding non-complementary matter and antimatter particles could conceivably produce other particles -- if they bother to interact at all :-) $\endgroup$ – Carl Witthoft Aug 13 '15 at 11:32
  • $\begingroup$ This answer might be more useful if it expanded a bit more on the reasoning. $\endgroup$ – Kyle Kanos Aug 13 '15 at 12:58
  • $\begingroup$ Can you explain a bit more ? $\endgroup$ – Tamim Addari Aug 13 '15 at 16:14
  • $\begingroup$ In particle physics, there are multiple conservation laws. Electrons and protons have a lepton number and baryon number respectively. If you initially have matter and its corresponding antimatter, the initial lepton and baryon number of the system is zero. This leads to the conclusion that it's not possible to only produce protons and electrons in such a collision because the final numbers would not be zero. It would be possible though to get protons and electrons IF there are other particles produced to maintain the conservation laws. $\endgroup$ – Complimentarity Aug 14 '15 at 3:15

Yes, and a good example of this is (or rather was) the LEP collider that preceded the LHC. This collided electrons with positrons, so it was a matter-antimatter collider just as you say, and the collisions created all sorts of particles including electrons and protons.

However, there are several symmetries that, as far as we know, have to be obeyed. Two of these are baryon number and lepton number. Baryon number is the number of baryons (e.g. protons and neutrons) minus the number of anti-baryons (e.g. anti-protons and anti-nuetrons). Likewise lepton number is the number of leptons (e.g. electrons, muons, neutrinos) minus the number of anti-leptons. A third symmetry is charge symmetry i.e. the total charge musn't change.

In the electron positron collision both the baryon and lepton numbers start at zero, so whatever flies out of the collision must also add up to a total baryon and lepton number of zero. So for every electron created there must be an anti-lepton such as a positron, anti-muon or anti-tau. In practice, after the anti-muon and anti-tau had decayed, we'd end up with the same number of electrons and positrons as well as various neutrinos.

It's a little more complicated with protons because protons are composite partices. However if we wait long enough for the unstable collision products to decay we'd end up with the same number of protons and anti-protons.


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.