Particle Physics : Now and the Future
David MilsteadStockholms 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 blocksof matter and what are the forces whichact 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-
q q
Z
g
Looking for a single super force !
Electromagnetism
Weak
Strong
Gravity ?
-
Anti-matter is rare (<<1%). Why ?
How do particles get mass ?
t
bcs
ude
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 energyin the universe
Supersymmetry
A new family of particles
Predicted to appear at the LHCOne 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 mammalsFirst DNA
Nu (15 billion years)Solar system
10-36 10-6 10-2
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 newparticles via E=mc2 -Higgs, SUSY etc..... The second most useful
relation in physics
LHCLarge Hadron Collider collides protons with energy 7 TeVIt 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 high7,000,000 kg 42m length 22m wide 22m high2,000 physicists 150 universities 34 countriesThe 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 with1 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
• 0.0002 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) + 3-4 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 physicsTravel, new languages and culturesFree to do what I find interestingNobody asks what I’m doing
Applying for new grants/fundingTravel – impossible to stay put for a monthNobody asks what I’m doing