There is something about phsyics
that has been really bothering me since I was a little kid.
And it's related to a question
that scientists have been asking for almost 100 years
with no answer.
How do the smallest things in nature --
the particles of the quantum world --
match up with the largest things in nature --
planets and stars and galaxies held together by gravity?
As a kid I would puzzle over questions just like this.
I would fiddle around with microscopes and electromagnets,
and I would read about the forces of the small,
and about quantum mechanics,
and I would marvel
at how well that description matched up to our observation.
And then I would look at the stars,
and I would read about how well we understand gravity,
and I would think surely there must be some elegant way
that these two systems match up,
but there's not.
And the books would say,
yeah, we understand a lot about these two realms separetely,
but we try to link them mathematically,
everything breaks.
And for 100 years,
none of our ideas as to how to solve this --
basically --
physics disaster,
has ever been supported by evidence.
And to little old me,
little, curious, skeptical James,
this was a supremely unsatisfying answer.
So I'm still a skeptical little kid --
well, flash-forward now to December of 2015,
when I found myself smack in the middle
of the physics world being flipped on its head.
It all started when we at CERN saw something intriguing in our data;
a hint of a new particle,
an inkling of a possibly extraordinary answer to this question.
So I'm still a skeptical little kid, I think,
but I'm also now a particle hunter.
I am a physicist at CERN's Large Hadron Collider,
the largest science experiment ever mounted.
It's a 27-kilometer tunnel on the border of France and Switzerland
buried 100 meters underground.
And in this tunnel,
we use superconducting magnets colder than outer space
to accelerate protons to almost the speed of light,
and slam them into each other millions of times per second,
collecting the debris of these collisions
to search for new, undiscovered fundamental particles.
Its design and construction took decades of work
by thousands of physicists from around the globe,
and in the summer of 2015,
we had been working tirelessly to switch on the LHC
at the highest energy that humans have ever used in a collider experiment.
Now, higher energy is important
because for particles there is an equivalence
between energy and particle mass,
and mass is just number put there by nature.
To discover new particles,
we need to reach these bigger numbers.
And to do that,
we have to build a bigger, higher energy collider,
and the biggest, highest energy collider in the world is the Large Hadron Collider.
And then we collide protons quadrillions of times,
and we collect this data very slowly over months and months.
And the new particles might show up in our data as bumps --
slight deviations from what you expect.
Little clusters of data points that make a smooth line not so smooth.
For example,
this bump,
after months of data taking in 2012,
led to the discovery of the Higgs particle,
the Higgs boson,
and to a Nobel Prize for the confirmation of its existence.
This jump up in energy in 2015
represented the best chance that we as a species had ever had
at discovering new particles --
new answers to these longstanding questions,
because it was almost twice as much energy as we used
when we discovered the Higgs boson.
Many of my colleagues had been working their entire careers for this moment,
and frankly,
to little curious me,
this was the moment I'd been waiting for my entire life.
So 2015 was go time.
So June 2015,
the LHC is switched back on.
My colleagues and I held our breath and bit our fingernails,
and then finally we saw the first proton collisions
at this highest energy ever.
Applause, champagne, celebration.
This was a milestone for science,
and we had no idea what we would find in this brand new data.
And then a few weeks later we found a bump.
It wasn't a very big bump,
but it was big enough to make you raise your eyebrow.
But on a scale of one to 10 for eyebrow raises,
if 10 indicates that you've discovered a new particle,
this eyebrow raise was about a four.
(Laughter)
I spent hours, days, weeks in secret meetings
arguing with my colleagues over this little bump,
poking and prodding it with our most ruthless experimental sticks
to see if it would withstand scrutiny.
But even after months of working feverishly --
sleeping in our offices and not going home,
candy bars for dinner,
coffee by the bucket full --
physicists are machines for turning coffee into diagrams --
(Laughter)
This little bump would not go away.
So after a few months,
we presented our little bump to the world with a very clear message:
this little bump is interesting but it's not definitive,
so let's keep an eye on it as we take more data.
And so we were trying to be extremely cool about it.
And the world ran with it anyway.
The news loved it.
People said it reminded them of the little bump
that was shown on the way towards the Higgs boson discovery.
Better than that,
my theorist colleagues --
I love my theorist colleagues --
my theorist colleagues wrote 500 papers about this little bump.
(Laughter)
The world of particle phsyics has been flipped on its head.
But what was it about this particular bump
that cause thousands of physicists to collectively lose their cool?
This little bump was unique.
This little bump indicated
that we were seeing an unexpectedly large number of collisions
whose debris consisted of only two photons --
two particles of light.
And that's rare.
Particle collisions are not like automobile collisions.
They have different rules.
When two particles collide at almost the speed of light,
the quantum world takes over.
And in the quantum world,
these two particles can briefly create a new particle
that lives for a tiny fraction of a second
before splitting into other particles that hit our detector.
Imagine a car collision where the two cars vanish upon impact,
a bicycle appears in their place --
(Laughter)
And then that bicycle explodes into two skateboards
which hit out detector.
(Laughter)
Hopefully not literally --
they're very expensive.
The events where only two photons hit out detector are very rare.
And because of the special quantum properties of photons,
we actually have --
there's a very small number of new particles --
these mythical bicycles --
that can give birth to only two photons.
But one of these options is huge,
and it has to do with that longstanding question
that bothered me as a tiny little kid
about gravity.