First collisions at the LHC with unprecedented Energy! (Ask a particle physisicist)

[Alex K]

Btw. the huge machine you see in the picture is used to hold just a minuscule amount of Antiatoms at once. The setup from Dan Brown's Angels&Demons is completely impossible with current technology, because it is super-difficult to trap just a few electrically neutral atoms without them touching the walls, let along grams of them.

[Aegon]

Rad. What does LHC stand for? Lsomething Hadron Collider?

Little

Little Hard-on Collider.....that's what my ex used to call me =/

[Alex K]

Little

Little Hard-on Collider.....that's what my ex used to call me =/

There's no newsworthy event at the LHC where there isn't *some* news outlet misspelling it.

[LastPoet]

My understanding of this is very limited.

Alex, do we know if anti matter forms atoms? Like an anti helium atom? If so, what would happen in am encounter between a heavier element and a lighter anti element? Or vice versa for that matter.

Yes, they are regularly produced (although only antihydrogen) e.g. at the CERN Antiproton Decelerator (AD), and analysed by experiments like ALPHA. I once had the opportunity to visit AD and ALPHA, impressive setup, not as big as the LHC stuff of course, but still impressive.

Producing heavier antiatoms deliberately is more difficult because you still have to make the antiprotons fuse after you produce them. Antihelium has however been observed as an accidental product of collisions afaik.
We know the laws of physics governing antimatter very precisely, and they are almost exactly (but not exactly) the same as those of matter. Antiatoms must have basically indistinguishable structure and spectra, and the same periodic table.

If an atom and and anti-atom of any type meet, the electrons and positrons in them will pair-annihilate into gamma rays, and the protons and neutrons will pair-annilhilate with the antineutrons and antiprotons into gamma rays, neutrinos etc.

So, if a anti helium meets a berilium atom, an helium atom will be left and a bunch of gamma ray photons? Or something else happens?

[Alex K]

Good question, I don't know whether the remainder of the beryllium again forms a stable core. If I had to guess, I'd say it gets blown apart and decays to protons and neutrons, but idk.

[LastPoet]

Yeah, given the amount of energy released by the anihilation.

[bennyboy]

If particles erupting out of space are in a natural state of equilibrium, wouldn't an imbalance necessarily mean that particles or energy are being injected into the Universe from outside it?  If so, would this make us a "matter" Universe on the whole, and is it possible that there is an "animatter-dominant" partner Universe in another dimension?  If so, wouldn't that mean that you don't have to search for any special mechanism, or that there might be none to be found?

I'm not sure how you come from a matter-antimattee imbalance to energy being injected. Antimatter has positive energy like normal matter (despite the name), they don't cancel each other out.
It is surely imaginable that there is some kind of mirror universe with the opposite contents, but that's pretty far out. It can't inhabit the same space as we do, we'd have noticed that through gravity.

What I mean is-- if there's an apparent imbalance, then one of the candidates for that imbalance would be that in fact there isn't one after all-- but that the surplus or missing material is elsewhere.

[Jackalope]

Good question, I don't know whether the remainder of the beryllium again forms a stable core. If I had to guess, I'd say it gets blown apart and decays to protons and neutrons, but idk.

You guess? C'mon, the math can't be that hard.

[Alex K]

Good question, I don't know whether the remainder of the beryllium again forms a stable core. If I had to guess, I'd say it gets blown apart and decays to protons and neutrons, but idk.

You guess? C'mon, the math can't be that hard.

Haha. I have trouble thinking of something that would be harder.

[Jackalope]

You guess?  C'mon, the math can't be that hard.  

Haha. I have trouble thinking of something that would be harder.

Take a mole of anti-helium and a mole of beryllium and smash them together at relativistic speeds. Calculate the composition, trajectory, and velocity of every resultant particle.

Show your work. Paper and pencil only. Closed book.