Matter And Antimatter, Conservation law for matter + antimatter

Is there a conservation law for matter (considered as +1 for each particle) plus antimatter (considered as -1 for each particle)?

Particular questions, where mcount for a system is defined as the number of matter particles - number of antimatter particles.

!) At the time of the big bang was the mcount of the universe 0?

2) In any particle reaction can the mcount change? If so, can you give an example?

3) (Follow up) If the answer to 1) is yes and the answer to 2) is no, where did the antimatter particles go?

There does seem to be such a law in fundamental interactions, provided you don't try to assign a non-zero number to gauge bosons.

Then all fundmental interactions look like one of the following:

• matter in, matter out, gauge boson in or out
• antimatter in, antimatter out, gauge boson in or out
• matter in, antimatter in, gauge boson out
• matter out, antimatter out, gauge boson in
• gauge boson in or our times 3 or 4

Various theories exist about why there is matter imbalance, but they will all seem to allow antimatter to convert to matter and do so preferentially, thus new laws of fundamental interactions would seem to be needed.

This post has been edited by rpenner on Jul 5 2010, 02:05 AM

There may be something missing from your list. For example neutron decay.
neutron -> proton + electron + anitneutrino.
Here the neutron and proton are both matter (3 quarks), while the electron and antineutrino balance.

My guess to keep the universal count in balance is to call the electron antimatter with the neutrino matter. When you do this the matter question becomes how did the antiprotons end up as electrons?

Neutron decay is not fundamental. It is composed of two of these fundamental interactions with gauge bosons.

down quark (mattter) in , up quark (matter) out , W- boson out
+
electron (matter) out, antineutrino (antimatter) out, W- boson in

Thus a neutron (udd) becomes a proton (uud) and a matter-antimatter couple comes into existence.


This has been studied by physicists under names like "Conservation of Baryon Number" and "Conservation of Lepton Number" where your quantity is
3 B + L, and so is conserved if the quantities physicists consider are conserved.

This post has been edited by rpenner on Jul 5 2010, 04:19 PM

Is it possible that the lepton pair that comes out have its identities reversed? Could it be electron (antimatter) and neutrino (matter)? Is there anything in the standard model which forces the electron to be labeled matter?

Nothing in the standard model framework requires electrons and the quarks in a proton to both be on the same side of the matter-antimatter fence. Presumable a GUT might have something to say here, but most of the naive GUTs have been rejected experimentally now, and the fancy ones still lack experimental support.

My speculation: conservation of matter + antimatter together with conservation of charge implies electrons are antimatter. Throw in enough antineutrinos to keep the overall blanace.

This could have already been previously posted but I couldn't find it in the history.

N/A

Evidence for an Anomalous like-sign Dimuon Charge Asymmetry

Evidence for an Anomalous like-sign Dimuon Charge Asymmetry

So this is the "toe" everyone has been looking for?