By “short-lived”, Chronos means on the order of a trillionth of a trillionth of a second. There isn’t enough time for the particle to interact with anything.
Stranger
Let’s ask/answer Tinopus’ question in a different way. If a proton (Up, up, down) meets an antineutron (anti-up, anti-down anti-down) do/can they interact by annihilating an anti-up with an up and anti-down with a down leaving an (up, anti-down) meson. I think that’s a pi+ meson.
I assume this is possible, though I don’t know how commonly it might happen.
Not a physicist, but AFAIK…
There’s a vast amount of space between subatomic particles, and they rarely collide with each other. The reason solid objects feel solid is because they have a layer of electrons on the outside, and electrons repel each other without touching. If “neutral” matter with no charge exists, it wouldn’t repel either electrons or positrons; instead of acting as a barrier, it would let both matter and antimatter just pass though. (Also, if the particles have no charge, there’s the question of what would hold it together in the first place.)
I’m sure I’m overlooking something here, though, that someone else will correct.
If a baryon collides with an antibaryon, the most probable first step is that they’ll turn into three mesons. That’s a process that can occur via the strong force, while what we think of as “annihilation” is an electromagnetic process, and strong processes are favored over electromagnetic ones. In this first step, the quarks may or may not be matched up with their corresponding antiquarks. If they are, then the mesons produced will be neutral, and can decay electromagnetically directly to photons, but if they’re not, then they’ll have to decay via the weak force.
Thus, for instance, a proton and an antiproton could give you three pi0 (about 1/3 chance), or it could give you one each of pi+, pi0, and pi- (about 2/3 chance). A proton and an antineutron could give you a pi+ and a pair of pi0 (about 2/3), or two pi+ and a pi- (about 1/3). The pi0 will decay into two photons each, while the chaged pions will probably first decay to a muon and a pair of neutrinos, while the muon will in turn eventually decay to an electron and another pair of neutrinos.
I think the OP is using neutral in the sense matter/antimatter, not in the sense of positive/negative.
In other words, he’s thinking that a molecule of H2 normally has two “matter” hydrogen bond together. If you one “matter” and one antimatter, they wouldn’t bond to form H2, they’d annihilate and leave you with nothing. So the idea of a “neutral” H (if I’m interpreting the OP correctly) is that you’d have a variety of hydrogen that could form H2 with a “matter” H and with an antimatter H.
Since an H molecule is itself electrically neutral, it’s not a matter of being positively or negatively charged, just a matter of how it reacts with anti/matter.
All that said, I really don’t think we have anything to offer but photons or other particles that are their own anti. The OP wants something else, but to my knowledge there is nothing else known or even theorized.
If there were something else, you’d probably expect it to be quite common. After all, it’s commonly believed that all matter in the universe is just a tiny percentage left over from a nearly equal amount of antimatter. If there was an option that couldn’t be annihilated, then you’d expect to see a lot of it, even if it was relatively rare to begin with.
Either I’m not understanding your point or what you’re saying here just doesn’t make sense. A normal single hydrogen atom in the ground state would have a single proton in the nucleus and an electron in the 1s orbital. An “antimatter H” atom would have one anti-proton in the nucleus and one positron in the 1s orbital. Combining these two together under normal conditions would result in both the electron/positron and proton/anti-proton pairs to be electrically attracted owing to having opposite charge. The electron/positron would produce a pair of high energy photons (gamma rays) and the proton/anti-proton would come together to the point that chromodynamic exchanges dominate over the electrical force and you’d end up with some annihilation of a quark/anti-quark pair and rearrangement of other quarks into mesons, which would then rapidly decay into photons, neutrinos/antineutrinos, and electrons/positrons with overall charge conservation (e.g. a net charge of zero). There are conditions in which matter and antimatter particles can be temporarily ‘frozen’ by careful control of quantum states (e.g. Bose-Einstein condensates) but by temporarily we’re still talking only nanoseconds in duration.
Again, there is no such thing as ‘solid matter’ at the atomic level or below. What we think of as being solid or continuous liquid is actually just due to a very precise balance of electrodynamic effects that exist as a quirk of stable quantum valance bonds, and if you could see close enough you’d realize that even these aren’t especially stable as there are reactions going on all the time at the interface (and often interstitial) levels of a solid material. Although we model this as slow diffusion, the reality is that particles at the atomic level are in constant, violent, unstoppable motion, and that solid materials have just enough stability to keep from flying apart. All of the things we think of as making a solid barrier against particles entering or leaving a vessel are purely electromagnetic fields which are joined by the constant exchange of virtual photons. Charged antimatter responds just the same way as matter, and so a Penning trap (which creates a closed path about which the particle can oscillate) can be used to contain antimatter away from interactions with the normal matter from which it is composed.
Stranger
You and dracoi are saying pretty much the same thing. You can’t have a liter of liquid hydrogen that is made up of mixed hydrogen molecules, where each molecule is made up of one “matter” hydrogen atom and one “antimatter” hydrogen atom. While someone might argue that they are the same “chemically,” they can’t exist in the bound state that two ordinary hydrogen atoms can.
So we know the answer is “no” for regular atoms and elements.
Are there “weird” things where this can work?
For example, an electron and a positron can get into a state where the orbit each other, forming a kind of pseudo-atom. But this is quite unstable, and breaks up super quickly. Still, it has a “metastability” and the quantum properties of this bound pair can be calculated.
(This was as far as I got in quantum physics in college: we did calculate the properties of a bound electron-positron pair!)
So, in a very limited way, the answer is “yes.” One of those “Yes, but…” situations.
This is quite a beautiful paragraph.
One more thing on
From a horribly influential text came the intriguing “Alles Ständische und Stehende verdampft,” which in its canonic and inaccurate translation in English is the exquisite “all that is solid melts into air.”
Phrase transitions.
Ouch.
Doesn’t it amount to the same thing? A molecule as a whole may be neutral, but the outer electron shell is negative. The outer positron shell of an antimatter molecule is positive, so they wouldn’t repel each other. They’d attract and both be annihilated. No?
I worked out a way to do what you want. Not easy but possible if you had the resources.
Step 1 : make anti hydrogen by pair production with intense lasers.
Step 2 : fuse the anti hydrogen by using massive magnets to squeeze it together. Very hard to do the initial fusion step (4 protons fusing) but stars do it.
Step 3: keep on fusing until you reach an element that is both solid and superconductive at 4 kelvin.
Step 4 : keep the solid disks inside a magnetic bottle. Super conductors reject magnetic fields so it would be very easy to contain. Also, heavier elements would have no vapor pressure at four Kelvin.
Step 5 : use laser tweezers to rip off tiny bits of the anti-beryllium or so fuel.
The only use I can think of that would be worth going to this much trouble would be to fuel a starship. Obviously, an engine that uses half antimatter as fuel could have enough impulse to reach a high enough fraction of the speed of light to reach another star probably within a few centuries.
Don’t be absurd, a generation ship is bad science fiction, a real starship would only contain a payload about the size and mass of a van or two, and the crew would not age, or be composed of human cells. Solving this problem is ironically much easier than solving the problem of building a vehicle loaded with hundreds or thousands of tons of antimatter fuel and expecting it to survive a centuries long journey.
Photons as mentioned above, but perhaps going further with it, photonic molecules might hold some yet to be discovered possibility for that.
(link does not mention antimatter containment.)