Particle Physics : Now and the Future David Milstead Stockholms Universitet The most important questions in modern physics The most important experiment in modern physics Physics as a career

Open questions for the curious physicist What are the fundamental building blocks of matter and what are the forces which act on them ? Why do particles have masses ? Why does nature seem to dislike anti-matter ? What is dark matter and dark energy ?

Nature’s building blocks (so far) proton W,Z,g,  force Standard Model of Particle Physics

Forces between particles e-e- e-e- e+ e- qq  Z g Looking for a single super force ! Electromagnetism Weak Strong Gravity ?

- Anti-matter is rare (<<1%). Why ?

How do particles get mass ? t b c s u d e Massa Peter Higgs theory explains why particles get mass. To prove the theory we must find a new particle: Higgs boson

Energy in the Universe Atoms Dark matter 25% Dark energy 70% We can’t understand 95% of the energy in the universe

Supersymmetry A new family of particles Predicted to appear at the LHC One of them could be dark matter

Story so far Protons are made up of quarks. What are quarks made up of ? Are there more quarks ? Can we find a single super force ? We can’t understand 95% of the universe’s energy – what is dark matter? Where did the anti-matter go ?

Go back to the start First mammals First DNA Nu (15 billion years) Solar system Matter-antimatter asymmetry The electromagnetic weak forces separate, Higgs Quarks become bound in protons sekunder Big bang + dark matter, dark energy.

microscope Accelerator Naked eye binoculars Telescope Measuring large and small objects Accelerators collide high energy particles to recreate the early universe and look inside a proton!

Collide a particle with a proton and study quarks We can also produce new particles via E=mc 2 -Higgs, SUSY etc..... The second most useful relation in physics

LHC Large Hadron Collider collides protons with energy 7 TeV It starts in 2007 Each proton beam has energy = aircraft carrier at 10 knots

LHC vs Stockholm’s underground LHC Blue line Length 27km 16 km Depth 100m 20-30m

ATLAS experiment Five levels high 7,000,000 kg 42m length 22m wide 22m high 2,000 physicists 150 universities 34 countries The goal is to discover new particles!

How can we find the Higgs boson/SUSY ? We are developing the WWWs successor: the Grid Concorde (15 Km) Balloon (30 Km) CD stack with 1 year LHC data! (~ 20 Km) Mt. Blanc (4.8 Km) Search through 20,000,000 collisions for one Higgs boson or several SUSY particles LHCs data corresponds to 14 million cds every year We will need 100,000 computers to analyse the data

We start with this And look for this signature in the mess Finding the Higgs boson 800,000,000 proton- proton interactions per second ~100,000,000 channels Higgs per second

Nature’s mirror doesn’t work Process B is a mirror image of process A. Process B uses the anti-particles of process A. We can measure a difference between them. Could explain why the early universe lost its anti-matter!

Summary of the physics LHC is one of the world’s most ambitious scientific projects It will address many of the most important questions in modern physics - What is mass ? - Matter anti-matter - Dark matter + much more.. Particle physics looks forward to a bright future

Research Physics as a career 3-4 years undergraduate (BSc/MSc) post-graduate (Ph.D.) 2:2 upwards required Be prepared to travel Be prepared for several short term post- doctoral jobs Can jump off at any point to a far more lucrative career

The best and worst aspects of my job Cutting edge physics Travel, new languages and cultures Free to do what I find interesting Nobody asks what I’m doing Applying for new grants/funding Travel – impossible to stay put for a month Nobody asks what I’m doing