what is the universe made of?
DESCRIPTION
What is the Universe Made Of?. by Bob Orr. The Higg, Dark Matter, Supersymmetry And The Large Hadron Collider. Plan of Talk. What we think visible matter is made of. The Standard Model Quantum forces Gauge Theories & Unification of Forces Cosmological Evidence for invisible matter - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/1.jpg)
What is the Universe Made Of?
by Bob Orr
The Higg, Dark Matter, SupersymmetryAnd
The Large Hadron Collider
![Page 2: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/2.jpg)
Plan of Talk
• What we think visible matter is made of.
• The Standard Model
• Quantum forces
• Gauge Theories & Unification of Forces
• Cosmological Evidence for invisible matter
• Supersymmetry
• Large Hadron Collider
• ATLAS
![Page 3: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/3.jpg)
Is the Universe Made of These?
Proton = (u u d) – held together by gluonsNeutron = (u d d)
![Page 4: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/4.jpg)
Quantum Forces
• In Quantum Field Theory, particles interact via:.
Exchange of virtual particles
Electrons interact by exchanging:
Virtual Photons
Quarks interact by exchanging:
Virtual Gluons
![Page 5: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/5.jpg)
Real & Virtual Particles
• Interactions of Real particles, conserve
Energy and Momentum.
• Interactions of Virtual particles, need not conserve these, for short times and distances.
• Hiesenberg’s Uncertainty Principle
E t
p x
Energy & time
Momentum & position
![Page 6: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/6.jpg)
Weak Interaction• A force very like electromagnetism; but
acts on Weak Charge
• Governs processes in stars ( beta-decay)
• In Fact, electromagnetism and weak forceare aspects of unified electroweak force
• Electric charge and weak charge are
related
• Three “force carriers”
W Z 0
W Z 0
![Page 7: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/7.jpg)
Electroweak Force
• Photon is massless
• are very massive
• Almost 100 times proton mass
W Z 0
3 Generations
0massZ
![Page 8: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/8.jpg)
Higgs Boson
• Electromagnetism on its own can be made to give finite results for all calculations.
• Unified Electroweak theory gives infinite results for process like:
• Become finite if include new particle
Higgs boson
• Higgs makes massive, and actually generates masses of fundamental particles. It is a quantum field permeating the universe.
W Z 0
![Page 9: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/9.jpg)
How Does Higgs Generate Mass?
• In vacuum, a photon:
has velocity c and has zero mass
• In glass a photon
has velocity < c , same as an effective mass
• This is due to photon interacting with
electromagnetic field in condensed matter
• By analogy can understand masses of particles
generated by Higgs Field in vacuum
![Page 10: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/10.jpg)
Grand Unification.
• At a high enough energy
electromagnetismweak forcestrong (colour) force
become aspects of Grand Unified Force
![Page 11: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/11.jpg)
Understand History of Universe?
• What we think (thought?) visible matter is made of.
![Page 12: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/12.jpg)
![Page 13: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/13.jpg)
Hubble’s Law & Big Bang.
• Big Bang model came from observation that
Universe is expanding
• For distant galaxies
velocity = x distance
is Hubble Parameter
• Whether Universe continues to expand, or starts to contract depends on density of matter and energy in Universe.
H0
H0
![Page 14: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/14.jpg)
Fate of Universe
• If , the density of matter and energy is greater that a critical density the universe will start to contract.
• If is less than the critical density, the universe will continue to expand.
• Usually measure the density in units of
• spherical space-time: contraction
• flat space-time: expansion
• hyperbolic space-time: expansion
0 c
0
c
00 0
02
8
3
c
G
H
0 1
0 1
0 1
![Page 15: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/15.jpg)
Measuring
• Amazingly enough can measure total matter/energy density in universe
• Measure temperature fluctuations in remnant of fireball from Big Bang.
0
0 1
Map of sky temp~ 3 Kelvin
![Page 16: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/16.jpg)
Measuring
• Amazingly enough can measure total matter/energy density in universe
• Measure temperature fluctuations in remnant of fireball from Big Bang.
0
0 1
Map of sky temp~ 3 Kelvin
![Page 17: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/17.jpg)
Measuring
• Amazingly enough can measure total matter/energy density in universe
• Measure temperature fluctuations in remnant of fireball from Big Bang.
0
0 1
Map of sky temp~ 3 Kelvin
![Page 18: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/18.jpg)
Density of Standard Model Matter
• Referred to as Baryonic Matter
• Density is
• If Universe is made of quarks & leptons
• measured from abundance of elementsproduced in nucleosynthesis of Big Bang.
Deuterium, Helium, Lithium
• Most of Universe is not Standard Model matter. Some kind of Dark Matter
B
B 0 1
B
B 0 05.
B 0
![Page 19: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/19.jpg)
Density of All Matter M
• Can measure density of all matter, whateverits nature, , by looking at gravitational motion:
rotation curves of galaxiesmotion of galactic clusters
• There is indeed Dark Matter
• So even with this Dark Matter, cannot account for
• Universe must be 60% Dark Energy
M
M 0 0 1.4 .
0 1
![Page 20: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/20.jpg)
Dark Energy
• If the expansion of the Universe is being slowed down by gravitational attraction; expect that in remote past galaxies were moving apart more rapidly than now.
• Observations of distant supernovae show that in the past galaxies were moving apart more slowly
• Expansion is accelerating
• Driven by some quantum field permeating the Universe.
0 85 0 2. .
( .4 . ) ( . . ) . .0 0 1 0 85 0 2 1 25 0 22
M 1
![Page 21: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/21.jpg)
![Page 22: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/22.jpg)
![Page 23: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/23.jpg)
Need for Supersymmetry
• In Grand Unified Theories cannot Unify forces, unless postulate unseen form of matter
• Higgs mass runs away to Plank Scale• Three forces never have same strength
• Unless all particles have supersymmetric sparticle partners (of higher mass)
+Sleptons BosinosSquarksSpin 1 Spin1/2
![Page 24: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/24.jpg)
SUSY + Dark Matter
• Supersymmetric Particles are unstable
• Eventually decay chain ends in Normal matter + lightest SUSY particle
• Lightest SUSYparticle cannot interact withnormal matter
• Lightest SUSY particle good candidate for
Dark Matter(Caveat - Recent evidence indicates that Dark Matter is Self-Interacting)
• Hope to produce
(SUSY - antiSUSY ) pairs and Higgs at
Large Hadron Collider
Susy Normal Susy
![Page 25: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/25.jpg)
How to Make Matter / AntiMatter?
LHC will be proton - proton collider
For SUSY observation must contain ALLvisible energy, in order to infer invisible SUSY
Colliding high energy beams
Energy of beams transformed into mass of new particles
![Page 26: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/26.jpg)
Superconducting Magnet
8 Tesla
In order to accelerate protons to high energy,must bend them in circular accelerator
7 TeV momentum needs intense magnetic field
![Page 27: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/27.jpg)
LHC Magnet
![Page 28: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/28.jpg)
LHC Tunnel
This is an arc of the circular tunnelCircumference 26.7 Km
![Page 29: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/29.jpg)
CERN Seen from the Air
• Tunnels of CERN accelerator complex superimposed on a map of Geneva.
• Accelerator is 50 m underground
![Page 30: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/30.jpg)
CERN Seen from the Air
• Tunnels of CERN accelerator complex superimposed on a map of Geneva.
• Accelerator is 50 m underground
![Page 31: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/31.jpg)
Generic Experiment
Layers of detector systems around collision point
![Page 32: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/32.jpg)
Particle Detection
• Different particles detected by different techniques.
• Calorimeter detects ionisation from a shower of secondaries produced by primary particle.
![Page 33: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/33.jpg)
Generic Detector
![Page 34: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/34.jpg)
ATLAS
• Our Detector
Canada is building
Endcap Calorimeters (TRIUMF Alberta, UVic)Forward Calorimeters (Toronto
Carleton)
![Page 35: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/35.jpg)
Forward Calorimeter
FCAL1 - Cu matrix + rods2.6
FCAL2/3 -W matrix, W rodsCu skeleton3.5/3.4
Side view of FCAL
• FCAL is mainly tungsten, uses liquid argonas detecting medium for ionisation from shower
• Close to colliding beams - intense radiation
Cryostat
![Page 36: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/36.jpg)
Hadronic Forward Calorimeter Principle
W (97%), Ni (2.1%), Fe (0.9%)
Tungsten rods in copper tubes in a matrix built of tungsten slugs
![Page 37: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/37.jpg)
FCAL2 Module 0
![Page 38: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/38.jpg)
FCAL2 Module 0
![Page 39: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/39.jpg)
FCAL2 Module 0
![Page 40: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/40.jpg)
Preliminary Results
Visible energy distribution for 200 GeV pions - both modules - tail catcher energy cut
Title:/afs/cern.ch/user/a/artamono/public/fcbtests98/distCreator:HIGZ Version 1.23/09Preview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.
![Page 41: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/41.jpg)
Preliminary Results
Pion Energy Resolution cf Monte Carlo
ATLAS Requirement (jets)
Test Beam Data&Fit
MC of Test Beam
MC Intrinsic Resolution.
![Page 42: What is the Universe Made Of?](https://reader030.vdocuments.us/reader030/viewer/2022033101/5681553e550346895dc31452/html5/thumbnails/42.jpg)
Higgs Discovery
End on View of a simulated Higgs Bosonproduced in the ATLAS Detector