the story of the universe - florida institute of...
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March 98v1
March 98
The story of the Universe
The story of the Universe
5
Quantum gravity era
Grand unification era
Electroweak era
Protons and neutrons form
Nuclei are formed
Atoms and light era
Galaxy formation
Today
The size of things
Particle Physics
From the Big Bang to today's Universe
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The story of the Universe
Quantum gravity era
6
10-43 s
?
t < 10-43 s : The Big BangThe universe is considered to have expanded from a single point with an infinitely high energy density (infinite temperature). Is there a meaning to the question what existed before the big bang?t ≈ 10-43 s, 1032 K (1019 GeV, 10-34 m) : Gravity “freezes” out All particle types (quarks, leptons, gauge bosons, and undiscovered particles e.g.Higgs, sparticles, gravitons) and their anti-particles are in a thermal equilibrium (being created and annihilated at equal rate). These coexist with photons (radiation).Through a phase transition gravity "froze" out and became distinct in its action from the weak, electromagnetic and strong forces. The other three forces could not be distinguished from one another in their action on quarks and leptons. This is the first instance of the breaking of symmetry amongst the forces.
Gravity separates as a force, the other forces remain as one (Grand Unification)
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The story of the Universe
Grand unification era
7
10-35 s
t ≈ 10-35 s, 1027 K (1016 GeV, 10-32 m) : Inflation The rate of expansion increases exponentially for a short period. The universe doubled in size every 10-34 s. Inflation stopped at around 10-32 s. The universe increased in size by a factor of 1050. This is equivalent to an object the size of a proton swelling to 1019 light years across. The whole universe is estimated to have had a size of ~1023 m at the end of the period of inflation. However the presently visible universe was only 3 m in size after inflation. This solves the problems of ‘horizon’ (how is it possible for two opposing parts of the present universe to be at the same temperature when they cannot have interacted with each other before recombination) and ‘flatness’ (density of matter is close to the critical density).
t ≈ 10-32 s : Strong forces freezes outThrough another phase transition the strong force "freezes" out and a slight excess of matter over anti-matter develops. This excess, at a level of 1 part in a billion, is sufficient to give the presently observed predominance of matter over anti-matter. The temperature is too high for quarks to remain clumped to form neutrons or protons and so exist in the form of a quark gluon plasma. The LHC can study this by colliding together high energy nuclei.
Inflation ceases, expansion continues Grand Unification breaks. Strong and electroweak
forces become distinguishable
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The story of the Universe
Electroweak era
8
10-10 s
t ≈ 10-10 s, 1015 K (100 GeV, 10-18 m) : Electromagnetic and Weak Forces separate The energy density corresponds to that at LEP. As the temperature fell the weak force "freezes" out and all four forces become distinct in their actions. The antiquarks annihilate with the quarks leaving a residual excess of matter. W and Z bosons decay. In general unstable massive particles disappear when the temperture falls to a value at which photons from the black-body radiation do not have sufficient energy to create a particle-antiparticle pair.
Electroweak force splits
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The story of the Universe
Protons and neutrons form
9
10-4 s
t ≈ 10-4 s, 1013 K (1 GeV, 10-16 m) : Protons and Neutrons form The universe has grown to the size of our solar system. As the temperature drops quark-antiquark annihilation stops and the remaining quarks combine to make protons and neutrons.
t = 1 s, 1010 K (1 MeV, 10-15 m) : Neutrinos decouple The neutrinos become inactive (essentially do not participate further in interactions). The electrons and positrons annihilate and are not recreated. An excess of electrons is left. The neutron-proton ratio shifts from 50:50 to 25:75.
Quarks combine to make protons and neutrons
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The story of the Universe
Nuclei are formed
10
100 s
t = 3 minutes, 109 K (0.1 MeV, 10-12 m) : Nuclei are formed The temperature is low enough to allow nuclei to be formed. Conditions are similar to those that exist in stars today or in thermonuclear bombs. Heavier nuclei such as deuterium, helium and lithium soak up the neutrons that are present. Any remaining neutrons decay with a time constant of ~ 1000 seconds. The neutron-proton ratio is now 13:87. The bulk constitution of the universe is now in place consisting essentially of protons (75%) and helium nuclei. The temperature is still too high to form any atoms and electrons form a gas of free particles.
Protons and neutrons combine to form helium nuclei
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The story of the Universe 11
Atoms and light era300000 years
t = 300 000 years, 6000 K (0.5 eV, 10-10 m) : Atoms are created Electrons begin to stick to nuclei. Atoms of hydrogen, helium and lithium are created. Radiation is no longer energetic enough to break atoms. The universe becomes transparent. Matter density dominates. Astronomy can study the evolution of the Universe back to this time.
The Universe becomes transparent and fills with light
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The story of the Universe 12
Galaxy formation1000 million years
t = 109 years, 18 K : Galaxy Formation Local mass density fluctuations act as seeds for stellar and galaxy formation. The exact mechanism is still not understood. Nucleosynthesis, synthesis of heavier nuclei such as carbon up to iron, starts occurring in the thermonuclear reactors that are stars. Even heavier elements are synthesized and dispersed in the brief moment during which stellar collapse and supernovae explosions occur.
Galaxies begin to form
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The story of the Universe 13
Today15000 million years
t = 15 x 109 years, 3 K : Humans The present day. Chemical processes have linked atoms to form molecules. From the dust of stars and through coded messages (DNA) humans emerge to observe the universe around them.
Man begins to wonder where it all came from
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Particles and forces 14
10-34
10-30
10-26
10-22
10-18
10-14
10-10
10-6
1m
106
1010
1014
1018
1022
1026
Earth radiusEarth to Sun
Galaxies
ObservablesInstruments
ProtonNuclei
Microscope
Telescope
RadioTelescope
VirusCell
Atom
SUSY particle?Higgs?Z/W (range of
weak force) (range of nuclear force)
(Particle beams)
ElectronMicroscope
Radius of observable Universe
Big Bang
Universe
LHCLEP
taAccelerators
The size of things
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The story of the Universe
Particle Physics
15
Aim to answer the two following questions
- What are the elementary constituents of matter?
- What are the fundamental forces that control their behavior at the most basic level?
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Particles and forces
Particles and forces
Particles
Forces
Interactions: coupling of forces to matter
Short history and new frontiers
Unification of forces
Summary
17
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Particles and forces 18
Tau
Muon
Electron
TauNeutrino
MuonNeutrino
ElectronNeutrino
Bottom
Strange
Down
Top
Charm
Up
Particles
Leptons
-1
-1
-1
0
0
0
2/3
2/3
2/3
-1/3
-1/3
-1/3
each quark: R, B, G 3 colors
Electric Charge
Electric Charge
Electric Charge
Electric Charge
Quarks
The particle drawings are simple artistic representations
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Particles and forces 19
Forces
Gluons (8)
Quarks
MesonsBaryons Nuclei
Graviton ? Bosons (W,Z)
AtomsLightChemistryElectronics
Solar systemGalaxiesBlack holes
Neutron decayBeta radioactivityNeutrino interactionsBurning of the sun
Strong
Photon
Electromagnetic
Gravitational Weak
The particle drawings are simple artistic representations
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Particles and forces
Interactions: coupling of forces to matter
20
u
Wd
e-
νe
Zo
e- e-
e+ e+
Strong
q
q
q'
q'
q q
q' q'
e- e-
g
gg
W
u d
e- νe
e- Zo
e+
e-
e+
Charged Neutral
g
g
g
Weak
Electroweak
qγ
q
e+
e-
γ
e+ e+
Electromagnetic
Range ∞, relative strength ≤ 10-2 Range ~10-18 m, relative strength 10-14
Range ~ 10-15 m, relative strength = 1
g
g g
g g
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Particles and forces 21
ud
cs
tb
eνe
µνµ ντ
τ
6 Quarks
6 Leptons
3 "Colors" each quark R G B
u e+Z
10-10 m ≤ 10 eV Quantum MechanicsAtomic Physics
>300000 Y
10-15 m MeV - GeV Nuclei, HadronsSymmetriesField theories
Quantum Electro Dynamics
10-16 m >> GeV QuarksGauge theories
≈ 10-6 sec
10-18 m ≈ 100 GeV ElectroWeak Unification, QCD
≈ 10-10 sec
1900....
1940-50
1950-65
1965-75
LEP 19903 families
10-19 m ≈ 103 GeVOrigin of massesThe next step...
≈ 10-12 sec
LHC 2005
SPS, pp 1970-83
λ = h / p T ≈ t -1/2
≈ 3 min
Higgs ? Supersymmetry ?
10-32 m ≈ 1016 GeV ≈ 10-32 secProton Decay ? GRAND Unified Theories ?
Underground Labs
10-35 m ≈ 1019 GeV(Planck scale)
≈ 10-43 secQuantum Gravity? Superstrings ?
??The Origin of the Universe
Top quarkTevatron 1994
e-u
Short history and new frontiers
γe+
e-
γ
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Particles and forces 22
Terrestrial mechanics
Universal GravitationInertial vs. Gravitational mass(I. Newton, 1687 )
Electricity
Magnetism
ElectromagnetismElectromagnetic waves (photon)(J.C. Maxwell, 1860 )
Electromagnetism
Weak force
Electroweak Intermediate bosons W, Z(1970-83 )
Probing shorter distances reveals
deeper regularities
UNIFIED DESCRIPTIONS
?
Unification of forces
Celestial mechanics
γγ
n
p
e-
νe
+ −
N S
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Particles and forces 23
10-43 sec 10-32 sec 10-10 sec 10-4 sec 100 sec 300000 years
10-35 m 10-32 m 10-18 m 10-16 m 10-15 m 10-10 m1019 GeV 1016 GeV 102 GeV 1 GeV 1 Mev 10 eV
Quantum Gravity
Super Unification
GrandUnification
Electroweak Model
QED
Weak Force
Nuclear Force
Electricity
Magnetism
Maxwell
Short range
Fermi
QCD
Long range
Short range
Terrestrial Gravity
Celestial Gravity
Einstein, NewtonGalilei
Kepler
Long range
?
Universal Gravitation
Electromagnetism
Weak Theory
Theories:STRINGS? RELATIVISTIC/QUANTUM CLASSICAL
Standard model
SU
SY
?
Summary