Answering Gauguin’s Questions
with the Large Hadron Collider
The world’s biggest scientific laboratory
John ELLIS
King’s College London (&
Where do we come from?
What are we?
Where are we going?
The aim of particle experiments at CERN:
What is the Universe made of?
Translating Gauguin’s Questions
into the Language of Physics
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What is matter made of?
Why do things weigh?
How was matter created?
What is the dark matter that fills the Universe?
How does the Universe evolve?
Why is the Universe so big and old?
Are there additional dimensions of space?
Our job is to ask (and answer?) these questions
Inside Matter
All matter is made of
the same constituents
What are they?
What forces between them?
From Cosmic Rays to CERN
Discovered a century ago …
… cosmic - ray
showers were
found to
contain many
different types
of particles …
CERN set up in 1954 to study these particles in detail
The ‘Standard Model’ of
Particle Physics
Proposed byAbdus Salam,
Glashow and Weinberg
Tested by experiments
at CERN
Perfect agreement between theory
and experiments in all laboratories
The ‘Standard Model’
The matter particles
= Cosmic DNA
The fundamental interactions
Gravitation
electromagnetism
weak nuclear force
strong nuclear force
Why do Things Weigh?
Newton:
Weight proportional to Mass
Einstein:
Energy related to Mass
Neither explained0origin of Mass
Where do the masses
come from ?
Are masses due to Higgs boson?
(the physicists’ Holy Grail)
Think of a Snowfield
Skier moves fast:
Like particle without mass
e.g., photon = particle of light
Snowshoer sinks into snow,
moves slower:
Like particle with mass
e.g., electron
The LHC will look for
the snowflake:
The Higgs Boson
Hiker sinks deep,
moves very slowly:
Particle with large mass
Imagine a
Room …
… Open
The Door
What lies
Beyond?
Dark
Matterininthe
theUniverse
Universe
Dark Matter
Astronomers say
that
most of tell
the
Astronomers
matter
in theof the
us that most
Universe
is
matter in the
universe is
invisible
invisible
Dark
Matter
‘Supersymmetric’ particles?
We will look for it
We shall look for
with the
LHC
them
with
the
LHC
Will LHC experiments create dark matter?
General Interest in Antimatter Physics
Physicists cannot make enough for
Star Trek or Dan Brown!
Where does the Matter come from?
Dirac predicted existence of antimatter:
same mass
opposite internal properties:
electric charge, …
Discovered in cosmic rays
Studied using accelerators
Used in medical diagnosis
Matter and antimatter not quite equal and opposite: WHY?
Is this why the Universe contains matter, not antimatter?
Will experiments reveal how matter was created?
Unify the Fundamental
Interactions:
Einstein’s Dream …
 … but he never succeeded
Maybe with extra dimensions of space?
To answer these questions:
The Large Hadron Collider (LHC)
Hundreds of thousands of billions of protons
Each with the energy of a fly
Primary targets:
99.9999991% of light speed
•Origin of mass
•Nature of Dark Matter
Orbit 27km ring 11 000 times/second
•Primordial Plasma
Up to a billion collisions a second
•Matter vs Antimatter
The Emptiest Space in the Solar System
Vacuum similar to interplanetary space:
the pressure in the beam-pipes is ten times
lower than on the Moon.
Cooler than Outer Space
LHC 1.9 degrees above absolute zero = - 271 C
Outer space 2.7 degrees above zero = - 270 C
Vista General
LHC y&sus
General
View del
of LHC
itsExperimentos
Experiments
27km in circumference
~ 100m deep
The Hottest Place in the Galaxy
Particle collisions create
(within a tiny volume)
temperatures a billion times higher than in
the heart of the Sun
ALICE: Primordial cosmic plasma
ATLAS: Higgs and supersymmetry
CMS: Higgs and supersymmetry
LHCb: Matter-antimatter difference
Some 3000 scientists and engineers
A thousand PhD students
38 countries
More components than a moon rocke
Assembling ATLAS
The LHC Roulette Wheel
Higgs boson
A Simulated Higgs Event
The LHC Roulette Wheel
Supersymmetry
Looking for Dark Matter @ LHC
Missing transverse energy
carried away by dark matter particles
The LHC Roulette Wheel
Extra dimensions
Will LHC experiments create black holes?
Eat up
the
entire
Earth?
Would
vanish
instantly
This may be why they were watching …
Start-up of the LHC:
Sept. 10th, 2008
A billion people watched on TV
Concentration, Anxiety …
… and tense
anticipation
Nov. 20th 2009: Jubilation
32
First High-Energy LHC Collision
The Story so Far …
Will LHC experiments show how mass is created?
First Higgs Event at the LHC
Interesting Events
viXra Blogger’s Combination
of March 7th Data
What is this?
No Higgs here!
Unofficial Combination of Higgs
Search Data from March 7th
Is this the
Higgs Boson?
No Higgs here!
No Higgs here!
No black holes yet!
A Global Adventure: over 10,000
Scientists from Around the World
CERN: where the World-Wide
Web was born
Tim Berners-Lee
• Invented to enable physicists around the world to collaborate
• The first on-line community
Accelerators are Us
30000 accelerators in the World
Most are used for medicine
Particles for therapy
Detectors are Us
PET (Positron Emission Tomography)
Localizes and study cancer
Uses antimatter (positrons)
Using nuclear isotope made by accelerator
Innovation is based on Fundamental Science
Electricity
and
Magnetism
Theory
of
Relativity
The LHC may revolutionize physics …
… and change our
view of the Universe
Conversation with Mrs Thatcher: 1982
What do you do?
Think of things for the
experiments to look
for, and hope they find
something different
Then we would not
learn anything!
Wouldn’t it be
better if they
found what
you predicted?