Okay everyone knows that when antimatter and normal matter combine there’s very substantial fireworks.
I’ve had a quick look and can’t find anything specific, hence the question here – does the antimatter & normal matter both have to be the same type? I mean if you injected a stream of anti-hydrogen into a container of normal hydrogen you’d get a large bang, but what if there was, say, nitrogen in the container?
Or does antimatter take pleasure in destroying everything & everything normal without discrimination?

Spiny Norman said:

Okay everyone knows that when antimatter and normal matter combine there’s very substantial fireworks.
I’ve had a quick look and can’t find anything specific, hence the question here – does the antimatter & normal matter both have to be the same type? I mean if you injected a stream of anti-hydrogen into a container of normal hydrogen you’d get a large bang, but what if there was, say, nitrogen in the container?
Or does antimatter take pleasure in destroying everything & everything normal without discrimination?

You’d think it would, but nitrogen has more protons than hydrogen, so it proton – antiproton cancellation only or could you get antiproton – 7 proton cancellation

Antihydrogen will react with “normal” matter even if it is not hydrogen, but it is best looked at at the subatomic level. The positrons will react with the electrons, annihilating one to one, and the energy will quickly ionise both antihydrogen and the target but what happens to the baryons (neutrons/protons) seems to depend on the exact nature of the collison. Each baryon is made up of three quarks (each antibaryon is made of three antiquarks), and from what I know the reaction is not likely to be complete, ie there may be an annihiliation of one quark and one antiquark to produce pions (and a lot of energy) but the energy will be enough to just scatter the remaining antiquarks and quarks to all quarters, to have separate reactions elsewhere. ie it is not as simple as a single antihydrogen atom partially annihilating a nitrogen atom.
https://cerncourier.com/a/fifty-years-of-antiprotons/

dv said:

Antihydrogen will react with “normal” matter even if it is not hydrogen, but it is best looked at at the subatomic level. The positrons will react with the electrons, annihilating one to one, and the energy will quickly ionise both antihydrogen and the target but what happens to the baryons (neutrons/protons) seems to depend on the exact nature of the collison. Each baryon is made up of three quarks (each antibaryon is made of three antiquarks), and from what I know the reaction is not likely to be complete, ie there may be an annihiliation of one quark and one antiquark to produce pions (and a lot of energy) but the energy will be enough to just scatter the remaining antiquarks and quarks to all quarters, to have separate reactions elsewhere. ie it is not as simple as a single antihydrogen atom partially annihilating a nitrogen atom.
https://cerncourier.com/a/fifty-years-of-antiprotons/

Ta. I suspected as much but I didn’t want to assume.

Spiny Norman said:

Okay everyone knows that when antimatter and normal matter combine there’s very substantial fireworks.
I’ve had a quick look and can’t find anything specific, hence the question here – does the antimatter & normal matter both have to be the same type? I mean if you injected a stream of anti-hydrogen into a container of normal hydrogen you’d get a large bang, but what if there was, say, nitrogen in the container?
Or does antimatter take pleasure in destroying everything & everything normal without discrimination?

If I understand correctly, it has to be the same type.

A positron will only interact by annihilation with an electron, not with a quark of any type or with a muon, photon, meson, proton, neutron, tau, W, Z, or graviton, Higgs or gluon.

Similarly an anti-down quark will only interact by annihilation with a down quark, not with an up quark or strange quark, or any type of lepton or gauge particle.

Even then, an electron and positron won’t annihilate to produce a single particle. The process tends to produce two photons, not one. Or at high energy can produce any particle-antiparticle pair.

Some particles are their own antiparticles, notably the photon, Z particle, Higgs, and neutral pion.

Neutrinos are not their own antiparticle (from recent experimental results).

mollwollfumble said:

Spiny Norman said:

Okay everyone knows that when antimatter and normal matter combine there’s very substantial fireworks.
I’ve had a quick look and can’t find anything specific, hence the question here – does the antimatter & normal matter both have to be the same type? I mean if you injected a stream of anti-hydrogen into a container of normal hydrogen you’d get a large bang, but what if there was, say, nitrogen in the container?
Or does antimatter take pleasure in destroying everything & everything normal without discrimination?

If I understand correctly, it has to be the same type.

A positron will only interact by annihilation with an electron, not with a quark of any type or with a muon, photon, meson, proton, neutron, tau, W, Z, or graviton, Higgs or gluon.

Similarly an anti-down quark will only interact by annihilation with a down quark, not with an up quark or strange quark, or any type of lepton or gauge particle.

Even then, an electron and positron won’t annihilate to produce a single particle. The process tends to produce two photons, not one. Or at high energy can produce any particle-antiparticle pair.

Some particles are their own antiparticles, notably the photon, Z particle, Higgs, and neutral pion.

Neutrinos are not their own antiparticle (from recent experimental results).

I should add two more points.

An antiproton can partially annihilate with a neutron. producing energy and leaving a lightweight pion meson behind.

With two exceptions that I know of, particles have the exact same mass as their antiparticles. Gravity does not act negatively on antiparticles. Those two exceptions are the Kaon and B meson, where the are are slight differences in mass between the particles and their antiparticles. See CPT symmetry for details.

mollwollfumble said:

Spiny Norman said:

Okay everyone knows that when antimatter and normal matter combine there’s very substantial fireworks.
I’ve had a quick look and can’t find anything specific, hence the question here – does the antimatter & normal matter both have to be the same type? I mean if you injected a stream of anti-hydrogen into a container of normal hydrogen you’d get a large bang, but what if there was, say, nitrogen in the container?
Or does antimatter take pleasure in destroying everything & everything normal without discrimination?

If I understand correctly, it has to be the same type. …

An antiproton can partially annihilate with a neutron. producing energy and leaving a lightweight pion meson behind.

And to follow up on that with anti-hydrogen + nitrogen.

A given mass of hydrogen contains twice as many electrons as the same mass of nitrogen. So after the reactions there would be a lot of electrons left over.

Equally, half of that given mass of nitrogen is of neutrons, and the annihilation between an antiproton and a neutron is incomplete, leaving a negatively charged pion.

So on an interaction between an equal mass of anti-hydrogen and nitrogen would leave a lot of positrons, and an equal number of negatively charged pions.

Pion mass is 140 Mev/c^2 and positron mass is 0.5 MeV/c^2
Proton mass is 938 MeV/c^2 and Neutron mass is 940 MeV/c^2

So the final mass in non-annihilated matter is 140.5 MeV/c^2 for every pair of anti-hydrogen atoms.
And initial mass is (3*938+940+3*0.5) = 3755.5 MeV/c^2 for every pair of anti-hydrogen atoms.

In other words, for the annihilation of anti-hydrogen with nitrogen, 140.5/3755.5 = 3.7% of the original mass would remain un-annihilated, with the remaining 96.3% converted into gamma ray energy.

The negatively charged pions decay into muons and anti-neutrinos. A muon eventually decays into an electron and a pair of neutrinos.

If these electrons hang around long enough then they can eventually annihilate with the positrons left over from the original annihilation. After which time all you would be left with is a sea of photons and neutrinos carrying away the energy.

mollwollfumble said:

mollwollfumble said:

Spiny Norman said:

Okay everyone knows that when antimatter and normal matter combine there’s very substantial fireworks.
I’ve had a quick look and can’t find anything specific, hence the question here – does the antimatter & normal matter both have to be the same type? I mean if you injected a stream of anti-hydrogen into a container of normal hydrogen you’d get a large bang, but what if there was, say, nitrogen in the container?
Or does antimatter take pleasure in destroying everything & everything normal without discrimination?

If I understand correctly, it has to be the same type. …

An antiproton can partially annihilate with a neutron. producing energy and leaving a lightweight pion meson behind.

And to follow up on that with anti-hydrogen + nitrogen.

A given mass of hydrogen contains twice as many electrons as the same mass of nitrogen. So after the reactions there would be a lot of electrons left over.

Equally, half of that given mass of nitrogen is of neutrons, and the annihilation between an antiproton and a neutron is incomplete, leaving a negatively charged pion.

So on an interaction between an equal mass of anti-hydrogen and nitrogen would leave a lot of positrons, and an equal number of negatively charged pions.

Pion mass is 140 Mev/c^2 and positron mass is 0.5 MeV/c^2
Proton mass is 938 MeV/c^2 and Neutron mass is 940 MeV/c^2

So the final mass in non-annihilated matter is 140.5 MeV/c^2 for every pair of anti-hydrogen atoms.
And initial mass is (3*938+940+3*0.5) = 3755.5 MeV/c^2 for every pair of anti-hydrogen atoms.

In other words, for the annihilation of anti-hydrogen with nitrogen, 140.5/3755.5 = 3.7% of the original mass would remain un-annihilated, with the remaining 96.3% converted into gamma ray energy.

The negatively charged pions decay into muons and anti-neutrinos. A muon eventually decays into an electron and a pair of neutrinos.

If these electrons hang around long enough then they can eventually annihilate with the positrons left over from the original annihilation. After which time all you would be left with is a sea of photons and neutrinos carrying away the energy.

Thanks for that.