Yeah, we're gonna talk about shining like three walls shining light through walls.

So there's a new type of particle that you can introduce to the standard model, and you introduce it because it solves some problems that exist in the interactions that make protons and neutrons so that the strong interaction So they're called acciones.

What it was That essay Axiron was originally the name of a brand of washing powder, I think, and the name was given to the particle because they clean up a mess that exists in the strong interaction.

What's this mess in the first place?

What needs cleaning up?

There's, ah, symmetry in the sector that shouldn't exist.

So your symmetry between particles and anti particles that actually we don't expect from the theory Well, that means is that there's one parameter one number that tells you how, whether this if that number is zero, the symmetry exists.

If the numbers non zero, then the symmetry doesn't make this, and what you expect is for that number to be large and for the symmetry to be completely, uh, broken.

But what we see when we D measurements is in fact that that that's what she's there.

So there's a number that you have to tune to be really, really small, and that's that's kind of uncomfortable from building theories.

We don't like having to make numbers really, really small.

If you had a particle on dhe, you flip its charge on dhe.

You do a reflection in space.

Um, if this symmetry exists, it tells you that you should get back to the same thing.

So flip the charge, invert everything to mirror effect everything.

Physics should look the same.

That's in fact what we see.

But the theory predicts that we shouldn't see that that there should be some differences when you when you do this into changing theory isn't quite matching.

What happens in reality, right?

You just invent a particle paper over the cracks that seems that's basically what we do in in physics.

That doesn't seem right to me.

That seems naughty, that see, that doesn't seem elegant.

Eso eso the idea.

The hope is actually that it's a more elegant solution.

So instead of having to have this one number being really, really small, what this new particle So this new particle replaces that number that you have to make really small.

And instead of just deciding that it's small and that's the end of the story, you have a way of explaining how it involves to be small.

Just about anything they can do actually on can undo.

This particle is postulated.

Yes, I was a problem for you.

What?

What would we know about it?

Would have a mass would have a charge.

What is it like?

A bit like like what if this particle exists about Yeah, it exists.

It has a mass that you don't know.

It has interactions with all of the other fields in the standard model.

In fact, that's what makes it really interesting, because these interactions give rise two simple things that we can then go and try and say, If this particle exists, can't we find it?

We're not just now going test for and like things apart and has people looking for you, absolutely.

And in fact, that's what this light shining through walls stuff is.

It's a way of trying to lick for these new particles because they interact with photons, say what can happen is as a fate on travel through a magnetic field, it could turn into an axiom.

So the idea of the experiment that people are doing this one at a lab in Hamburg, in Germany at the moment that their buildings the idea is you have a big magnet when you shine a laser beam.

Three.

The three, the core of the magnet, and he put a wall in the middle.

It's a laser on one ends camera on the other wall in the middle, so you shouldn't be seeing any light in the camera.

But if these acciones exists, as the photons from the laser beam travel through the moment field, they can turn into actions, and the actions don't care about the wall.

They very happily travel through the wall.

And then, if you're lucky, the reverse process happens on the other side, you're actually turns back into a fate on, and that's what you see in your camera.

The other side.

What you need is a really strong, really long magneto, and then you can try and find Point XY owns.

The nice thing about this experiment is there's there's no background you.

If fact seasons don't exist, you expect to see nothing so if you see something that tells you an accent, is that soon as you see something you know that's an accident.

You've got a limited number of photons in your laser beam.

You know, the more photons you can put into your magnet, the higher the chance that one of them turns into an axiom.

So that's the kind of engineering challenge of doing this.

Getting as many photons inside your magnetic field as he can, turning up the magnetic field strength this?

No, it's not like photons or a scarce commodity.

You just could shine the laser for years and just wait for one to happen right on.

And that's what people people are trying to do.

In fact, it's just it's just a case of getting the money building their kit bond, then leaving it to run basically, has this big boo.

Is this running or not?

So that the it's called the Alps experiments of the any light particle search or axiom like particles that on a first iteration of it ran a couple of years ago for particle physics, A cheap thing to do because they've been able Thio essentially cannibalize some old magnets that used to be part of a particle collider.

Um, and use those 10 days in T Interacciones that So they did this kind of a proof of concept a couple of years ago, and now they're building 100 meter long detector to try and search for actions that should be coming.

That should be turning one in a couple of years.

Because you know so little about acciones you don't know.

How likely is that The photons gonna turn into accidents?

It could have been very likely.

And if we'd have been lucky, the experiment that already ran would have seen it.

We weren't that lucky.

So it's a lot rarer than that.

So you have to sort of just keep running your experiment with more sensitivity.