- [Crew] So you brought us in here
to tell us, after all this,
that there's more we don't know?
(laughs)
(plucky music)
- Where to start?
There's been a discovery
it was announced yesterday
that indicates there's potentially new physics
that we don't know of.
(laughs) I know it's a big statement!
Fermilab in Illinois is where this experiment was done.
Have you ever heard of the standard model?
Have you ever seen anything that looks like this?
- Yeah. - Yeah?
This is basically all the particles that we know of
and all the forces that we know of,
electrons, protons, everything that make over our atoms.
There's evidence from this experiment
that there's maybe something beyond that.
This is huge because the standard model
has been like, a work of decades.
It comes from theory and experimentation,
and one of the last particles that
we had theorized from the standard model
and then discovered was the Higgs Boson,
which was that massive experiment at CERN.
So, for there to not even be theorized particles,
you know what I mean? - Yeah.
- It's not even in our theory,
it's just evidence that there's something beyond our theory.
Beyond our theory and beyond anything we've ever seen.
So, that is what this announcement means.
Or potentially means.
So, I say potentially because
what the experiment was that was just announced,
it's not precise enough for it to be
considered a big scientific announcement.
Okay, so what it is is very complicated. (laughs)
Have you ever heard of a muon?
No! Great, okay.
But you've heard of electrons.
They're in these terrible models of atoms.
There are other particles that are not as common.
They are actually a lot of them,
for example, the Higgs boson.
Another example is neutrinos,
and then another example is the muon.
And the muon is, oh--
The muon was discovered in 1936
because they were looking at
the way that electrons move in a magnetic field.
And then they see another particle come through,
and it has a much wider arc.
And they're like, "What the heck is that?"
So if you've ever heard that,
if you've got just a uniform magnetic field
and you shoot a charged particle through it, it'll curve.
Have you heard of this?
Okay, does it make sense?
Okay, good, I'm glad I asked.
What is another example of this happening?
Oh, in CERN!
The reason that particles go around and around
is because they're charged particles and
they're going around in these
big magnetic fields, and it makes them curve.
And then when they collide and all this stuff comes off,
they're watching how they curve in a magnetic field.
That's why you see all these spiral lines
coming off of the collision, because
if a particle has a negative or a positive charge,
it'll curve one way or the other way in a magnetic field.
If it doesn't have a charge at all, like a neutron,
it just goes straight.
So you'll see those spirals,
and then you'll see the straight lines.
So there's these guys, and then they see
another particle come through,
and it has a much wider arc.
Much wider means that it has more mass.
So they found this particle, they're like "What is that?"
It turns out it is just like the electrons,
a lot of people call it the cousin to the electron,
but it has 207 times the mass.
Oh, so that's when they discovered the muon.
If you had a bunch of muons
instead of electrons in your atoms,
you would be way heavier.
I don't know how much heavier.
Um, okay so!
The measurement that was just made was that--
Ugh, this is the part where it's going to get really tricky.
You know how a top that's spinning
will kind of wobble around?
If the top were in space, it wouldn't do that.
It would just spin, it wouldn't wobble.
The reason that it's wobbling is because
it's spinning in a gravitational field,
and gravity is having an effect on the top
and making it wobble.
Can you accept that?
Good, 'cause I don't want to go in--
Similarly, there's another really
complicated property of particles called spin.
It's not like the particles actually spinning,
it's just a property, but
when you put a particle with magnetic magnetic spin
in magnetic field, it'll wobble in a similar way.
The amount that it would wobble
is something that we can predict.
Say that the amount of wobble is supposed to be two.
The amount it's supposed to wobble
is called the G factor,
and the theoretical number is
supposed to be two for the muon.
Now there's something else weird that we've theorized,
which has that the wobble should also be affected by
(laughs)
something that people call quantum foam.
Have you heard of the idea that
there are constantly particles
popping in and out of existence
in the vacuum of space?
Yeah, okay.
So those particles popping in and out---
When that happens, they can interact with a particle,
a real particle that exists like a muon,
and then they can affect that wobble.
I know that this is getting to the point
where it's like, okay,
what is the point of all of this?
We've got quantum foam effecting the wobble,
but we're almost there.
And we have a number for that,
and it's like, it's close to the two.
It's like 2.00, and then there's this added correction,
2, 3, 3, 1 8 3 6 2 0.
8,6 and the eight six in parentheses for the error.
Now that's obviously a very precise,
theoretical measurement.
12 digits of precision that we think we know,
the theoretical amount of the effect of the wobble
from the quantum foam.
They did a measurement of the G factor,
of the amount of wobble, and they saw
it didn't match the theoretical number.
So it didn't match it by...
Tn the last four digits of that 11 digit you saw,
instead of 3, 6, 2 0, you saw a 4, 1, 2, 2.
- [Crew] So does this already mean that
the foam is not causing it?
- No, it doesn't mean that the foam is not causing it.
It means that there's probably particles
that we don't know of or forces we don't know of.
Because we have such a precise idea of
how the wobble should change
based off of known particles,
and how we know they pop up into existence.
So, if we measure something different,
most likely it must be that the physics is different.
- [Crew] So you brought us in here to tell us,
after all this, that there is more we don't know?
(laughs)
The newest discovery in physics,
we might know less than we thought!
- But it's, it's the way that
we don't know more that's important!
- [Crew] Physicists.
- It's not like, "Oh, we don't know
what happened before the big bang."
It's like, no, we're seeing evidence
for something specific to go look for.
Right here's the moment when physicists are like,
"Oh my God, let's go look for new particles!
Let's go look for new forces."
Okay, maybe it's not that important to you
to go look for new particles,
but have you seen CERN, it's huge!
Like that entire experiment was looking
for one new particle.
- [Crew] I wonder what they're going to do
to look for what's making that change.
- I know, I know!
There's nothing specific to look for yet
because it doesn't fit our theories!
Like, when we looked for the Higgs boson,
it was part of the standard model theory.
Yeah, it was like, there's the Higgs right there.
Here's a grayed-out box of a particle we have a theory for,
and then we discovered it and like, boop!
Fill that in with a color.
But we're seeing an anomaly.
We're seeing something act differently than
we ever predicted before.
- [Crew] It's like winning a bingo and then
someone's like, look, a alphabet.
- Or it's like winning at bingo,
and then you get another bingo card.
Bingo plus!
- [Crew] Yeah, that's pretty crazy.
It doesn't fit the standard model.
- I know!
So it could be new particles, new forces,
or something wrong about our current theory.
But we know so much about our current theory,
and so many of our very expensive,
very precise experiments have verified what we know.
So for the idea that some of it to be wrong is almost as
inconceivable as for there to be new particles
and new theories, which is also inconceivable at this point.
But yeah, it's exciting.
- [Crew] How come they're confident
there's something really big to find?
Why can't it just something they haven't thought of?
Anything magnetic on earth?
Where we are, our place in the galaxy?
- So one reason that they're confident about this result
is that it was done before, in 2001.
So it was originally done in Brookhaven National Labs
in 2001, and it was such a big result at the time
that they're like, "We have to verify this."
And so they took the big ol' magnet,
a big superconducting magnet,
50 foot in diameter, here it is.
See that red thing?
That's the magnet arriving at Fermilab
to a big party and a big celebration
because it was transported 3,200 miles to upgrade it.
I went to Fermilab in 2016,
and the only picture I took besides like,
oh, this is a pretty view down the building,
was of this diagram
that shows the path that the magnet took.
So this is not technically a discovery yet.
And the reason I said that is because
you need a certain amount of certainty.
You need a certain certainty
to consider a scientific announcement
as like, an actual discovery.
And you need it to be something called Five Sigma,
which is just like, a statistical amount.
The exciting thing is that they verified a result from 2001,
But, again, normally, and rightfully,
five Sigma is the amount of certainty that
you usually need to make this type of announcement.
So, since they're only at 4.2 Sigma
scientists are being careful and saying like,
"Yes, this is exciting.
We verified a result from a previous experiment,
so that's promising, but
it's not promising enough
because we don't have enough certainty."
They're going to keep it here,
and they're going to upgrade the experiment
for future runs get more precision.
The chance that this measurement is a random fluctuation,
like a random statistical error
in the measurement is one in 40,000.
Like not enough that I would bet my life on, but--
- [Crew] These are usually so small or so big,
that's like, weirdly a normal number.
Physicists are usually talking about like
the billions or the quantum.
- Right, right right right.
We know enough of that
to make a good enough prediction of
what the change in this little wobble, G factor, should be,
and we see something
different.
That's it!
Big announcement.
Yay, okay. And cut.
So actually, when I was doing my experiment
looking for dark matter in college,
when we first turned it on,
one of the first things we saw was a muon.
PI, the person running the experiment, was like,
"Oh, see that blip, that signal?
That's a muon."
We just detected these cosmic ray muons,
which are these particles raining down.
- [Crew] That device, was it used to detect muons?
- We were making a detector that was looking for
actually neutrons.
All of these are just different particles.
And the device was like this,
I'm making it this big, but it was actually like--
I dunno, what's here to here, ten feet?
In this big chamber full of this fluid called scintillator.
It's a really cool fluid, because if you just like,
barely look in there, you see a little glow.
So a particle will come through this scintillator
and they'll cause it to glow along the path.
And then we had detectors on either end
that would capture the light,
and so you'd see, oh, a particle came through.
Cause we got a little bit of blip of light,
which meant that something came through our scintillator.
That's how the detector worked.
So we turned it on, and we were like,
we got a little flash of light, that's probably a muon.
We just saw a cosmic ray muon.
Any more questions? Okay.
The other really cool thing that muons were used for
was to verify one of the predictions
of special relativity from Einstein,
specifically time dilation.
And this was a long time ago, 1941.
Have you heard of time dilation?
The basic idea is that if we were moving really fast,
like if I was jetting through the universe,
then time would tick slower for me, which is cool.
There's a lot, I mean, there's a lot more to it.
Basically time ticks differently
depending on whether you're moving or not.
If you went and traveled around the earth
a bunch of times in a really fast rocket ship
and came back, you would have aged less
than I would have aged.
That was a prediction of relativity,
but not verified until later.
And one of the verifications was
this really cool experiment.
The thing about muons is that
they don't live very long.
They have a mean lifetime of 2.2 microseconds.
But there are a lot of them,
constantly raining down on us,
because a lot of them are produced when cosmic rays
come from the universe and they hit our atmosphere.
Imagine you can measure how many muons there are,
like go up on top of a hill and measure how many
are coming through a little area,
and then go down to the bottom of the mountain,
and you know how fast these muons are supposed to decay.
So you should go to the bottom
and you should only see a certain number,
because the rest of them should have decayed.
But what happened is they saw more at the bottom
than they should have, more were surviving.
But what that means is that,
because these muons are going so fast
time is ticking slower for them.
They're actually not decaying because
they haven't reached that mean lifetime.
So that was a verification of
this idea of relativity.
Does that make sense?
- [Crew] I read Ender's Game. (laughs)