Presented by Laura Johnson, Catherine Jones, Catherine Cutts and Victoria Green

The Neutron

The Proton

The ElectronCharge: -e

Antimatter equivalent:

the positron

Charge: +e

Antimatter equivalent:

Anti-proton

Charge: 0

Antimatter equivalent:

Anti-neutron

10-18

m

10-15

m

10-10

m

10-14

m

100 km!

2 x giraffe height

10 m

Large ruler

1m

Ant width

1mm

An atom

The nucleus

A proton

Electrons

? ?

?

If we had some way of breaking this particle apart…

Is a neutron…

…fundamental?

…we could find out!

What could lie inside?

The search begins!

Originally physicists investigated sub-atomic particles using cosmic rays.

When cosmic rays from space hit big atoms (e.g. lead) smaller particles were sprayed out. At high altitudes there are more cosmic rays so they went to the tops of mountains to conduct their experiments.

Physicists started to build devices which accelerated particles to near to the speed of light and collide them target atoms.

The resulting pieces from the collision are analysed and tell us about what’s inside the particles…

…Kind of like smashing a watch to find out how it works!

LEAD

A modern day particle accelerator

CERNLocation: Geneva, 100 meters underground

Circumference: 27km (making this the worlds largest machine!)

Speed: can accelerate protons to 99.9997828% of the speed of light

s

s

ss

It takes a long time (and distance) to get the particles up to the required speeds so to save space the track is circular (like at CERN!).

The charged particle is accelerated by large voltages and kept moving in a circle by magnets.

Target particle

Electron

Inside a particle accelerator..

Electron

Positron

Inside a particle accelerator..

•Quarks

•Leptons (electrons etc.)

•Neutrinos

These are traces of where the particles have been. We analyse them and then figure out what they are.

(Charged particles move in circles in a magnetic field)

Quarks are one of two things that make up all matter!

There are 6 types of quarks

The name originally came from the book Finnegans Wake where seabirds give "three quarks“ like the quack of ducks...The charges of quarks are fractions of the charge on an electron. This all adds up, as you’ll soon see!!

Up +2/3

Down -1/3

Charm +2/3

Strange -1/3

Top +2/3Bottom -1/3

The quarks make up the inside of protons and neutrons.

The Up and Down Quarks are the only quarks that are in normal matter. The stuff you and me are made of!

+2

/3e

-1/3

e

-1/3

e

neutron

-1/3

e

+2

/3e

+2

/3e

proton

No charge!

+e charge!

Quarks cannot be separated. The force that holds them together is too strong.

If you pull enough in the quarks, two other quarks will appear in between them.

The leptons are a family of elementary particles (particles that cannot be broken into smaller pieces). The lightest one is the electron.

There are two other different types of leptons, the muon and the tau. Muons are found in cosmic rays (high energy particles that come from outer space).

(Each of these has a related neutrino, which we’re going to talk about now)

Neutrinos have a very, very low mass, (so low that we have only just proved that they have a mass at all!)

They can pass through the whole of the earth without being stopped no force acts on them much.

It is very hard to detect neutrinos.

And we try and detect them by using:

• 470 tonnes of ‘dry cleaning fluid’

• A deep, underground mine

• A team of keen physicists

• There are three types of neutrino (one for each lepton)

Electron neutrinoMuon neutrino Tau neutrino

• They come from nuclear decay, for example in the sun. When a supernova occurs there is a burst of them.

• Neutrinos might be part of dark matter, since we cannot detect them easily and there are lots of them. But we don’t think it can make up much, because their individual masses are soooo small.

I’m

fre

eeeeeeeeeee

Gravitational Electro-magnetic

Weak nuclear

Strong nuclear

Weight Friction

Air resistance

Reaction

Tension

Magnetic

Electrical

Radioactivity Holds protons together

So, what next? Lets look at forces..

Yes, that’s it, there are really only four forces.

The big bang… An extremely high temperature…

Theoretically, all four forces were unified at the big bang and also can be unified at extremely high temperatures (only we’ve not

managed to created such a high temperature yet!). But that still doesn’t explain why particles have mass…

The bowl that is full of sweets is like a particle. You are like a Higgs field.

The bowl is harder to get moving because the field is around it.

If the bowl had different sweets in it, it might be slowed down more.

The particle is slowed down according to its mass. (i.e., the number of sweets in the bowl)

This is like the Higgs Field at work!

A bowl without sweets is like a particle with no mass, for example light.

If I started a rumour and it passed around the room, the field would be disturbed without there being anything there. The Higgs boson is like this clustering.

The Higgs field is what give the particles their mass.

The LHC is going to look for this as well as lots of other things. If it doesn’t find it, we’ll be very surprised…

….and a completely new theory will have to be developed to explain why particles have mass!

Particle physics is based around answering these two main questions:

- What are the fundamental (smallest) building blocks from which all matter is made up of? - What are the interactions between them that govern how they combine and decay?

Our research so far has lead to: - the world wide web - extreme development in computer processing power - understanding of basic quantum technology

What we could achieve: - (quantum) superior computers, - (quantum) dynamic treatment for diseases - (strong and weak forces) a near-infinite energy supply

This presentation wasbrought to you by

Laura JohnsonCatherine JonesCatherine CuttsVictoria Green

of

Nottingham High School for Girls

With thanks to

Mr PriceMrs Bell

And

The University of Birmingham, for all the resources they have provided