What on earth is What on earth is Particle Physics?Particle Physics?

Divine KumahDivine Kumah

European Particle Physics European Particle Physics LabLab

Geneva, SwitzerlandGeneva, Switzerland

The Big WHAT and WHYThe Big WHAT and WHY

People have long asked, People have long asked,

"What is the world made "What is the world made of?" of?"

"What holds it "What holds it together?" together?"

•Ancient Belief that matter consisted of 4 elements:•EARTH •WIND•FIRE•WATER

What is matter made up What is matter made up of?of?

Matter we can see and touch

Atoms made up of Protons, Neutrons and Electrons

Molecules

A Brief HistoryA Brief History

YearYear ExperimenteExperimenterr

DiscoveryDiscovery

18971897 ThomsonThomson ElectronElectron

19091909 RutherfordRutherford NucleusNucleus

19321932 ChadwickChadwick NeutronNeutron

19321932 AndersonAnderson AntimatterAntimatter

19561956 Reines, Reines, CowanCowan

NeutrinoNeutrino

Since 1956Since 1956 Quarks, leptons, tau, pionsQuarks, leptons, tau, pions

What are Atoms?What are Atoms?

We used to think We used to think that atoms were that atoms were the fundamental the fundamental particles.particles.

Atoms Nucleus and ElectronsProtons and Neutrons

Guess WHAT?Guess WHAT? We were wrong!!! We were wrong!!!

Can we get more Can we get more FunFun--damental?damental?

Yes!Yes!Particle Physicists have discovered Particle Physicists have discovered

that we matter is made up of more that we matter is made up of more elementary particles which can be elementary particles which can be classified into classified into

I. I. Quarks Quarks

II. II. LeptonsLeptons

After extensively testing

this theory, scientists now

suspect that quarks and

the electron (and a few

other things we'll see in a

minute) are fundamental.

What are Quarks and What are Quarks and Leptons?Leptons?

QuarksQuarks combine with each other to make combine with each other to make

matter particles like protons and matter particles like protons and neutrons neutrons

LeptonsLeptons are particles like electrons. Unlike the are particles like electrons. Unlike the

quarks, they do not combine with each quarks, they do not combine with each other to make other particles other to make other particles

The Building BlocksThe Building Blocks

UpUp DownDown

TopTop BottomBottom

CharmCharm StrangeStrange

QuarksQuarksElectronElectron Electron Electron

NeutrinoNeutrino

TauTau Tau Tau NeutrinoNeutrino

MuonMuon Muon Muon NeutrinoNeutrino

Matter consists of elementary particles which Matter consists of elementary particles which can be divided into quarks and leptonscan be divided into quarks and leptons

LeptonsLeptons

How do we know?How do we know?

How do we see stuff so How do we see stuff so small??small??

We really cannot directly see these tiny particles but we can identify them based on the way they act in our experiments.

How Do we Study the How Do we Study the Particles?Particles?

The two “toys” used to study sub-The two “toys” used to study sub-atomic particles are atomic particles are Particle Accelerators and CollidersParticle Accelerators and Colliders

Particles such as electrons, protons and Particles such as electrons, protons and ions are accelerated in electromagnetic ions are accelerated in electromagnetic fields and bombarded into other particles fields and bombarded into other particles and studiedand studied

Particle DetectorsParticle Detectors Special gadgets used to study the products Special gadgets used to study the products

(energy and momenta) of collided particles(energy and momenta) of collided particles

A Particle DetectorA Particle Detector(A Toroidal LHC Aparatus)(A Toroidal LHC Aparatus)

How it Works•Consists of layers like an onion•Different Layers detect different products•All Information fed to a computer system for reconstruction and analysis

Unanswered QuestionsUnanswered Questions

Are quarks and leptons made up of Are quarks and leptons made up of other particles?other particles?

Where does mass come from?Where does mass come from? Are there some other fundamental Are there some other fundamental

forces?forces?

Review.Review.

What do we find in the nucleus of an What do we find in the nucleus of an atom?atom?

What are the two categories of the What are the two categories of the fundamental particles?fundamental particles?

How many quarks do we have?How many quarks do we have? How many leptons do we have?How many leptons do we have? Do you want to be a particle Do you want to be a particle

Physicist?Physicist?

Website ReferencesWebsite References

www.fermilab.govwww.fermilab.gov www.llnl.govwww.llnl.gov www.cern.chwww.cern.ch www.particleadventure.orgwww.particleadventure.org www.phys.subr.edu/TA/spswww.phys.subr.edu/TA/sps

Questions???Questions???