Transcript What`s All The Fuss About??? - Elementary Particle Physics Group

What Caused It?
A singularity formed by a previous
collapsed Universe?
Multiple Universes?
We just don’t know… YET
What Happened?
AND How?
 96% of our universe seems to be
missing.
 We don’t know what it’s made from?
 Dark Matter? It seems to exist but
scientists have no idea what it
actually is.
Scientists Believe They Can
Look Back To
0.00000000000000000000000000000000
00000000001
seconds after the moment of creation
You would have needed a
microscope to see it!
What is this…?
What is it…?
 A theory of how the universe works.
 A description of how the fundamental
particles that make up all matter interact
with each other.
 12 fundamental particles
 4 fundamental forces
Fundamental Forces
Force
Range
Strength
Acts between:
STRONG FORCE
10-15 m
Strongest
Quarks
Stronger than WF
Charged
objects
ELECTROMAGNETIC No limit
WEAK FORCE
10-18 m
Stronger than G
Fundamental
Particles
GRAVITY
No limit
Weakest
All objects
Classification
 According to the SM, matter can be divided
into 3 blocks:
 FERMIONS
 BOSONS
 HADRONS
Fermions
• Subatomic particles that make known
matter and antimatter.
• Consists of QUARKS and LEPTONS.
• Found in the nuclei of atoms
• Not found in nuclei
• Mainly make up protons and
neutrons
• e.g. electrons
Bosons
 Bosons are particles that carry forces.
•There are 4 known bosons:
• GLUON: strong force
• W & Z: weak force
• PHOTON: electromagnetic force, and
operates over an infinite distance.
•THEORETICAL:GRAVITON: gravity, and
operates over an infinite distance.
Hadrons
 Hadrons are composite particles made up
of quarks, e.g. protons and neutrons.
 These can be found in the nucleus of an
atom.
Large Hadron collider
What's All The Fuss
About???
The LHC
• Was built to help scientists answer
key questions
• May reveal some unexpected results
What Are these “Unresolved
Questions”?
1) What is mass?
• What is the origin of mass?
• Why do tiny particles weigh the amount they
do?
• Why do some particles have no mass at all?
• The most likely explanation could be the
Higgs boson
• First hypothesized in 1964,
• It has yet to be observed.
An Invisible Problem...
2) What is 96% of the universe made of?
• Matter forms 4% of the Universe.
• The rest, Dark matter and dark energy?
• Investigating this 96% is one of the biggest
challenges today in the fields of particle
physics and cosmology.
Nature's Favoritism...
3) Why is there no more antimatter?
• Everything we see in the Universe is made of
matter.
• Antimatter has opposite electric charge, but
identical in every other way.
• At the birth of the Universe, more matter than
antimatter was produced in the Big Bang.
MATTER + ANITMATTER  ENERGY
Why does Nature appear to have this bias for
matter over antimatter?
Secrets of the Big Bang
4) What was matter like within the first second
of the Universe’s life?
• Matter is believed to have originated from
fundamental particles.
• Today, the composition of matter comes down to
gluons.
• During the first microseconds after the Big Bang
the Universe would have contained quark–gluon
plasma.
Large Hadron Collider
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The world’s largest and most powerful particle
accelerator.
38,000 tonnes
27 km ring of superconducting magnets
Number of accelerating structures to boost the energy
of the particles along the way
9300 magnets
Trillions of protons racing around the LHC ring at over
11000 times a second.
Traveling at 99.99% of the speed of light.
600 million collisions every second
What Goes On Inside???
 Inside the accelerator,
• Two beams close to the speed of light
• Very high energies
• Beams travel in opposite directions
• Guided by a strong magnetic field.
• Chilling the magnets to about -271°C
 A temperature colder than outer
space!
• Temperatures up to 1000 times hotter than the
centre of the Sun!
The accelerator complex
When will it Launch?
• First need to cool the machine down to almost
absolute zero
• If there is a problem with the machine can cause
a delay of up to 3 months.
LHC is on course for a start-up as early as this
summer.
World Ending?
 Concerns about the safety of the high
energy particle collisions.
• Mini black holes
• Mini Big Bangs
Overall no reasons for concern!
The key to Mass
What Is Higgs?
 A few years ago scientists hit a problem, they
could not explain how mass exists!
 They came up with the Higgs mechanism
 The Higgs mechanism is the unproven
quantum phenomenon that gives massless
particles mass.
The Higgs Field– a simple explanation
In this explanation the famous person is a particle and the
people are the Higgs field.
Imagine a Hollywood party. In the
beginning the people are evenly
distributed in the room.
When someone famous walks into the
room the people are attracted to them.
As the famous person moves through the
room they gain momentum, this is an
indication of mass.
The Higgs Particle– A Simple Explanation
In this explanation the people in the room are Higgs Bosons
Imagine the same Hollywood party. In
the beginning everyone is spread
evenly in the room.
Then someone starts a rumour at the
door and a few people hear it and
group together.
As the rumour moves through the
room it gains momentum and
therefore it has gained mass.
Higgs at the LHC
If the Higgs exists,
the LHC can
transfer more than
enough energy to
detect it.
Even if the Higgs
is proven incorrect,
the LHC will find
something.
Whatever the LHC
finds will be
revolutionary