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Black Holes, the LHC and the God Particle. Dr Cormac O’Raifeartaigh (WIT). The Big Bang, the LHC and the God Particle. Cormac O’Raifeartaigh (WIT). Overview. I. LHC What, why, how II. A brief history of particles From the nucleus to the Standard Model III. LHC Expectations - PowerPoint PPT Presentation
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The Big Bang, the LHC and the God Particle
Cormac O’Raifeartaigh (WIT)
Black Holes, the LHC and the God Particle
Dr Cormac O’Raifeartaigh (WIT)
Overview
I. LHC
What, why, how
II. A brief history of particles
From the nucleus to the Standard Model
III. LHC Expectations
The God particle
Beyond the Standard Model
Cosmology at the LHC
E = mc2
The Large Hadron Collider (CERN)
No black holes
Particle accelerator
Head-on collision of protons
Huge energy density
Create short-lived particles
Detection
Why
I. Explore fundamental constituents of matter
Investigate inter-relation of forces that hold matter together
II. Study early universe
Highest energy since BB
T = 1019 K
t = 1x10-12 s
V = football
• Puzzle of antimatter• Puzzle of dark matter
Cosmology
E = kT → T =
How
Ultra-high vacuum
Low temp: 1.6 K
v = speed of light
E = 14 TeV (2.2 µJ)
LEP tunnel: 27 km Superconducting magnets
600 M collisions/sec (1.3 kW)
Particle detectors
4 main detectors
• CMS multi-purpose
•ATLAS multi-purpose
•ALICE quark-gluon plasma
•LHC-b antimatter decay
UCD group
Particle detectors
Tracking devicemeasures momentum of charged particle
Calorimeter measures energy of particle by
absorption
Identification detector measures velocity of particle by Cherenkov radiation
Matter and Energy
Matter is a form of energy
E = mc2
Energy is a form of matterm = E/c2
→ Create matter and antimatter from energy
Antimatter
Predicted by Dirac Equation
Electron of opposite charge
Detected 1932
All particles have opposites
Why is universe dominated by matter?
Black Holes
• Huge mass shrunk to tiny volume
• Extreme gravitational field
• Light, matter ‘trapped’
Huge energy required
m = E/c2
II Particle physics (1930s)
• Atoms (1909) Brownian motion
• The atomic nucleus (1911) Rutherford Backscattering
• Proton (1918)
• Neutron (1932)
Protons and the Periodic Table
• Fundamental differences in atoms
no. protons in nucleus
• Determines electron configuration
• Determines chemical properties
What holds nucleus together? What causes radioactivity?
Strong force (Yukawa, 1934)
strong force >> em
charge indep (p+, n)
short range
Heisenberg Uncertainty
massive particle
3 charge states
Yukawa pion (1947)
Yukawa
Weak force (Fermi, 1934)
Radioactivity (B decay)
Electrons from nucleus? no p+ + e- ?
But: energy, momentum missing
New particle; tiny mass, zero charge neutrino
no p+ + e- + (confirmed 1956)
Four forces of nature Force of gravityHolds cosmos togetherLong range
Electromagnetic force Holds atoms together
Strong nuclear force: holds nucleus together
Weak nuclear force: Beta decay
Walton: accelerator physics
Cockcroft and Walton: linear accelerator Protons used to split the nucleus (1932)
Nobel prize (1956)
1H1 + 3Li6.9 → 2He4 + 2He4
Verified mass-energy (E= mc2)Verified quantum tunnelling
Cavendish lab, Cambridge
New particles (1950s)
Cosmic rays Particle accelerators
LINACS (Walton)synchrotronsπ+ → μ+ + ν
Particle Zoo (1950s, 1960s)
Over 100 particles
Quarks (1960s theory)
p not fundamental
new periodic table
symmetry arguments
new fundamental particles quarks
Up, down, strange
prediction of -
Gell-Mann, Zweig
Quarks (experiment, 1970s)
Stanford experiments 1969
Scattering experiments
Similar to RBS
SF = interquark force!
defining property = colour
confinement
infra-red slavery
The energy required to produce a separation far exceeds the pair production energy of a quark-antiquark pair
Quark generations (1970s –1990s)
30 years experiments
Six different quarks(u,d,s,c,t,b)
Six leptons (electron sisters)
(e, μ, τ, υe, υμ, υτ)
Gen I: all of ordinary matter
Gen II, III redundant?
Electro-weak force (1970s)
Electromagnetic + weak forces = e-w force
Single interaction above 100 GeV
Predictions: W+-,Z0 bosons
Detected: CERN, 1983
Mediated by new particles W, Z
Higgs mechanism to generate mass
Rubbia, Van der Meer Glashow, Salaam and Weinberg Nobel prize 1979
Nobel prize 1984
The Standard Model (1970s)
EM + weak force = electroweak
Strong force = quark force (QCD)
Force between quarks caused by colour
Matter particles: fermions
Force particles: bosons
Standard Model: 1980-1990s
• experimental success but Higgs boson outstanding
key particle: too heavy?
III LHC expectations (SM)
Higgs boson
Determines mass of other particles
Set by known mass of top quark, Z boson
120-180 GeV
Search…surprise?
Main production mechanisms of the Higgs at the LHC
Ref: A. Djouadi,hep-ph/0503172
Ref: hep-ph/0208209
Higgs search: summary
Expectations II: Beyond the SM
Unified field theory
Grand unified theory (GUT): 3 forces
Theory of everything (TOE): 4 forces
Supersymmetry
symmetry of fermions and bosons
improves GUT (circumvents no-go theorems)
gravitons: makes TOE possible
LHC
Supersymmetric particles?
Extra dimensions?
Expectations III: Cosmology
High E = photo of early U
1. Superforce:SUSY particles?
2. SUSY = dark matter? neutralinos? double whammy
3. Missing antimatter ? LHCb
LHCb (UCD)
Tangential to ringB-meson collectionDecay of b quark, antiquarkCP violation (UCD group)
• Where is antimatter?• Asymmetry in M/AM decay• CP violation
b-quarks, W,Z bosons June 2010
SummaryHiggs boson (God particle)Close chapter on SM
Supersymmetric particlesOpen chapter on unification
CosmologyMissing antimatterNature of dark matter
Surprises New dimensions - string theory?
Further reading: ANTIMATTER
Epilogue: CERN and Ireland
World leader
20 member states
10 associate states
80 nations, 500 univ.
Ireland not a member
No particle physics in Ireland…..almost
European Organization for Nuclear Research