cern, 31 january, 2001 egil lillestøl, cern & univ. of bergen this lecture is being recorded...

CERN, 31 January, CERN, 31 January, 20012001CERN, 31 January, CERN, 31 January, 20012001Egil Lillestøl, CERN & Univ. of BergenEgil Lillestøl, CERN & Univ. of BergenEgil Lillestøl, CERN & Univ. of BergenEgil Lillestøl, CERN & Univ. of Bergen

This lecture is being recorded and will be viewable on the

Web from Friday 2nd February at –

http://wlap.web.cern.ch/


10 7 m

Large structures and Orders of Magnitude


Sun (Eclipse)

corona

10 9 m

Sun ≈ 2x1030 kg ≈ 1057 (protons + neutrons)

nucleons


10 11 m

Earth Orbit


Milky Way


Spiral Galaxy

100 000 light years = 10 21 m

10 11 stars


Galaxy Cluster (Hercules)

10 23 m

Thousands of Galaxies


Hubble Deep Field


A Foamy Universe (bubbles 200 Mly across)


10 21 m 10 22 m 10 23 m

10 24 m 10 25 m 10 26 m

10 11

galaxies

10 22

stars

Summary of the largest structures

1080

nucleons


Dominated by Matter and Gravity **(1011 galaxies, 1022 stars)

Described by General Relativity

(or Newtonian Mechanics)

** This is far from the whole truth !!


Where it all came from

15 billions = 1.5 x 10 12

years ago

and since thenever expanding


Will the Expansion ever stop ?

Inflation predicts a flat universe.

This means that the Density of Matter and Energyequals the so called critical density

Ordinary Matter can account for only up to5% of the critical density

Dark Matter Problems


The First Dark Matter problem:these Galaxies should simply not exist !

Need a spherical halo of matter around the galaxy

So:is there

invisible (dark) matteraround the

galaxy ?


speed

200km/s

distance from center

predicted

measured


Gravitational lensing

Distant galaxy

Foreground cluster

Observer

109 light years

2x 109 light years


Reconstruction of Mass Distribution(250 times more matter than expected from light output)


Large amounts of invisible (dark) matter

Can NOT be ordinary matter :- does not interact with light- does not interact with ordinary matter- does concentrate around galaxies and in galaxy clusters.

What is it ???

If the answer is Super Symmetric Particles,

LHC will find it !!


The Second Dark Matter problem:The dark matter seems to make uponly 30-50% of the critical density

This may be linked with observations ofa possible accelerating expansion ofthe universe at large distances.

Study of type 1a Supernovae

(1a Supernovae ≈ standard light sources)


1a Supernova:

white dwarfaccompanying star


Far away* supernovae seem to be too far away !

Very difficult observations, but if true could mean:

Resurrection of Einstein’s Cosmological Constant,or “Qintessence” - one more possibility of

Exotic Matter ????Need more astronomical data

Need the LHC for a better understanding ofdark matter

* for specialists - red shifts z ≈ 1


The Smallest Structures

where Quantum Mechanics reigns, andwhere particles are waves, and waves are particles

Heisenberg’s Uncertainty Relation:

(x)(p) ≈ h/(2) or (t)(E) ≈ h/(2)

h is Planck’s constant - a very small number, (6.6x10-34Js)x is position, p is momentum,t is time, and E is energy.(x) means uncertainty in position, etc


Electrons (10-18 m )

Atom nucleus nucleon quark

10-10 m 10-14 m 10-15 m 10-18 m

Constituents of matter

see


Stable (ordinary) matter:

one up quark (charge +2/3)

one down quark (charge -1/3)

one electron (charge -1)

one neutrino (no charge, “no” mass)

proton

neutron

But for what do we need the neutrino??

leptons

compositeparticles

nucleons


The Forces of Nature(what is a force?)

Newton and Gravity

Faraday and Fields

Forces as “Exchange” Particles

An important difference between Matter Particles and Force Particles:M.P. obey Pauli’s Principle, i.e. only one particle for each quantum state.F.P. does not have this constraint and can clump together.

This is why Matter appears to be Solid


Is the Quantum World a Fuzzy World?

The answer is a clearNO !

QM means that all thequalities of the subatomicworld and by extension ofeverything can be exactly quantified !

Photon, E = h


Can not use light microscopes to study atoms !!!

Quantum mechanics tells us thatparticles behave like waves and visa versa:

h/p

Use electron microscopes

LEP the world’s biggestelectron microscope

electron


electron

quark

New Stuff from E = Mc2

New, unstable particles, can NOT be explainedas made up of up and down quarks only.

High Energy electron-proton scattering


Creating New Matter with LEP

Need two more generations of quarks


How does a point in empty space know exactlythe variety of particles it can produceand all their properties and their forces .... ???

Back to Heisenberg and Faraday:Particles and Forces are Quantum Fields fillingevery point of “Empty” Space (or the “Vacuum”).

The Fields materialize as Particles whenEnergy is fed into this Vacuum.

Structures are temporary, the Pattern lasts for ever !


electron(energy U)

U= 1 eV= 1.6x10-19J(speed at positive plate18 000 km/s)

1 keV = 103 eV1 MeV = 106 eV1 GeV = 109 eV1 TeV = 1012 eV

LEP = 209 GeVLHC = 14 TeV

Practical Units

- +

1 Volt


Einstein: E = Mc2

pc

use units such that c =1 E (GeV or MeV)p (GeV/c or MeV/c)M (GeV/c2 or MeV/c2)

M0c2Mproton = 0.931 GeV/c2 ≈ 1 GeV/c2 Melectron = 0.5 MeV/c2

( Mtop = 170 GeV/c2 )

proton diameter = length scale:10-15 m = 1 fermi (femtometer)

E

Special Relativity:( E2= (pc)2 + (M0c2)2 )

cern, 31 january, 2001 egil lillestøl, cern & univ. of bergen this lecture is being recorded...

Documents

bergen slide

egil lillestl

bergen speed

bergen electrons

bergen milky way slide

star slide

measured slide

matter particles