Kind: captions
Language: en
We are on our way to CERN in Geneva. And
this is Jean Mark, the cameraman. Hi.
And uh we should be coming up on it.
That's the dome. That's the famous CERN
dome up ahead.
Ah, this is pretty exciting.
[Applause]
On July 4th here at CERN, an historic
announcement was made. A new particle
had been discovered, most likely the
sought-after Higs Bzon.
As a layman, I would now say I think we
have it.
You agree?
Yeah.
The finding made news around the world
and led to an outpouring of emotion from
the normally restrained particle physics
community.
For the discoverers themselves, it was
particularly momentous.
Wow. I mean, it was I've never seen
physicists like this. It really looks
beautiful. I cannot tell you how
beautiful it is. It makes you cry how
beautiful it is.
That's why we're here essentially, you
know, that that's that's the reason why
I I'm doing particle physics.
But now that this particle has been
found, what's left to do at the Large
Hadron Collider? Let's find out.
Our current understanding of the
universe is based on the modestly named
standard model, a theory of all
fundamental matter particles and their
interactions.
Virtually all of the standard model has
been verified apart from one crucial
element.
What gives matter its mass? And to be
clear, that is absolutely critically
important even to our daily existence.
Because if an electron would be
massless, it could not be bound to a
proton. You could not have an atom and
then you know sort of all of you know
the stars, the planets, chemistry, life
couldn't couldn't exist because instead
of electrons bound to protons in in
hydrogen atoms and in and in larger
atoms instead you would just have
electrons whizzing off to infinity.
In the standard model, mass is explained
by the Higs mechanism of which the Higs
Bzon is only one part. For example,
you've probably heard that the Higs Bzon
gives mass to the other subatomic
particles. But if that were true,
shouldn't there be Higs Bzons
everywhere? I mean, why would it be so
difficult to create and detect them?
Well, in truth, it's not the particle
itself that gives mass to the other
particles. It's the Higs field.
You can think of the Higs field as a
huge sea of honey that fills all space.
Some particles are able to travel
through it unimpeded whilst others
interact with it, slowing down in the
process and that translates into mass.
When enough high energy is added to the
field, fleeting Higs bzons are created.
So in order to discover the Higs
particle, we needed to invest energy by
the collision in the Higs field and
create the Higs particle out of it. And
then we'll know that indeed we have a
Higs. And that's what this incredible
machine does. Using powerful magnets,
the Large Hadron Collider whizzes two
beams of protons in opposite directions
around a 27 km circular tunnel. When the
protons collide, their energy can be
converted into the mass of new particles
like the Higs Bzon. Short-lived, these
particles decay quickly, and it's their
decay products which are then analyzed
by massive detectors.
This is the giant apparatus at the CMS
detector. It's one of two major
detectors on the beam line where the
protons collide. You can actually see a
life-siz picture of the CMS detector. I
am standing above the beam line. And so
there's protons whizzing around
underneath my feet right now, 90 m under
the ground at speeds that are basically
the speed of light. 99.9999999%
the speed of light. You may as well just
be the speed of light, but of course a
proton can never reach that speed.
These are some big toys.
The other big experiment examining
proton collisions is called Atlas.
The teams at Atlas and CMS, each made up
of about 3,000 scientists, work
independently in a sort of friendly
rivalry. uh
is it actually friendly?
Yes, of course it is. I mean we uh what
we what we always say is that uh of
course it's essential that if if there's
a major discovery which is made that
it's confirmed ultimately by the two
experiments and independently and that's
why the discovery announced earlier this
year was so dramatic. Both detectors saw
the same results more or less
simultaneously.
Protons are bags of other particles.
When they smash together, a mess of new
particles is created. And it's the
pattern of the debris that provides the
answers.
What they saw was evidence of a new
particle with a mass of between 125 and
126 ga electron volts.
And then we see these two large blobs of
energy in the calerime. And you can see
them over here.
If you added those two bits of energy
together, what total energy would you
get? I think in this one you get 125 GV.
So that seems to be exactly what we'd be
expecting if it's a
Hig with gamma gamma.
But the question now is if it is a Higs,
is it the Higs as predicted by the
standard model?
Are you willing to to make a bet about
what kind of Higs Bzon is? Do you think
it's the standard model Higs?
Wow, that's a difficult one. No, I
wouldn't bet my life on uh I might bet
my life that we discovered the Higs, but
I wouldn't bet my life that it is the
standard model Hicks. It's very
difficult to tell.
All we know is it's there. We we almost
know nothing about its properties and
its properties are key really to tell us
exactly what it is.
So to find out the LHC will conduct many
more collisions and this should allow
scientists to determine the properties
of the new particle.
If it is not standard model Higs, we may
be able to tell that early. We could
even tell that this year. As an example,
uh both experiments saw a bit too many
photons. Too many times the Higs was
decaying into photons. more than you'd
expect.
more than you'd expect. And in the case
of
strangely, that's exactly what these
guys are hoping for, that it doesn't fit
the model perfectly, that it's not the
standard model Higs.
Let let's say that the reason for doing
science is of course we're looking for
answers, but generating more questions
is is an inevitable and and one of the
most exciting uh pieces of of of the
scientific procedure.
And what would that help you determine?
I mean, if it's not standard model Higs,
that's a big thing. If it's not standard
model Higs,
then we know that there's new physics
for sure. And if the new physics is
along the lines that we expect, then we
have something pretty profound as a
possibility. One would be additional
spatial dimensions. Okay, that's one
possibility. Another would be really
almost a mirror image of the entire
universe in terms of particles. That's
super symmetry. And and these things
would be extremely profound.
Whether it turns out to be the standard
model Higs or something even more
profound, one thing is for sure. The
discovery of this new particle is a huge
milestone in the long quest to uncover
the fundamental laws of nature.
[Music]
I see.
[Music]
When it goes up,
[Music]