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The Big Bang, the LHC and the God Particle
Cormac O’Raifeartaigh (WIT)
Faster than the speed of light
Was Einstein wrong?
Cormac O’Raifeartaigh (WIT)
Overview
I The OPERA experiment
What, why, how
II Relativity (special)
Theory and experiment
III Relativity (general)
Theory and experiment
IV Skepticism in science Coda: a mundane explanation
The OPERA experiment
Result: early by 60 nanoseconds
Beam of neutrinos at CERN
Detector under Gran Sasso
Distance of 732 km
Time of flight 2.43 ms
0.003% faster than light !
Neutrinos
• Suggested by Pauli (1930)
• Conservation of energy
• Particle of zero charge, low mass
• Weak interaction
Skepticism Detected in 1956
Neutrino puzzles
• Tiny mass (non-zero?)
• Created in nuclear reactions • The solar neutrino paradox
Three different types Neutrino oscillation
OPERA experiment
Standard Model
neutrino = lighter cousin of electron
The OPERA experiment
OPERA: The numbers
Measurement of distance (GPS)
732 km +/- 20 cm
• Time of flight (GPS)
2.43006 ms +/- 10 ns
Velocity = distance/time Δv/v = 2.5 x 10-5 (25 ppm)
Note: proton pulse 10 μs long (10,000 ns) 60 ns early (18 m??)
OPERA: The snags
Not direct comparison Light does not travel through mountain
Accurate measurement of distance Relies on GPS
Accurate measurement of time-of-flight Relies on GPS and statistics (pulses)
Relatively short distance/timeNeed to direct beam at the moon
Systematic error ?
II The theory of relativity (special)
• Laws of physics identical for observers in uniform motion• Speed of light in vacuum a fundamental constant
Length contraction
Time dilation
Mass increase
220 /1)( cvLvL
220 /1/)( cvtvt
220 /1/)( cvmvm
E = mc2
Implications for bodies at high speed
Early experiments Kaufmann, Bucherer
Particle accelerators Length contraction
Time dilation Mass increase
Modern particle accelerators Speed limit
Particle creation E = mc2
Evidence for relativity
CERN (Geneva)
• energy increase
• velocity increase?
K.E = 1/2mv2
mass increases
220 /1/)( cvmvm
Relativity ‘skepticism’
• Extraordinary concept• Counter-intuitive • Only observable at tremendous speeds• Only observable for subatomic particles
• Simple maths• Time and distance calculations • Personalization• Confusion of discovery and justification
Speed of light plays role of infinity
Dr Al Kelly ‘Einstein wrong’
III The general theory of relativity
Gravity = curvature of space and time
• Laws of physics identical for all observers• Speed of light in vacuum a universal constant• Principle of equivalence
• New view of gravity• Cosmological implications
Matter warps space and time
General Relativity (1915)
General relativity (evidence)
• Bending of starlight by sun Eddington experiment
• Time dilation by gravity Pound experiment
• Expanding universe Hubble’s law
• Geodesic effect Everett experiment
Breakdown at quantum scales
Skepticism from astronomy
Supernova• Huge implosion of massive star• Light released• Neutrinos released
Supernova 1987a• Neutrinos detected• Light detected• Time difference of 5 min
Not 5 years !
IV Skepticism in science
Many years for new result to be accepted
Must be reproducible
Must fit known data
• Paradigm shift• Slow, gradual process (DJ)• Consensus process
If so
Compare: accelerating universe
Thomas Kuhn
Skepticism in the media
Scientific skepticism misunderstood
Attributed to conservatism
Role of evidence misunderstood
‘Balanced’ debate unweighted
Science journalism: news driven
Bjorn Lomborg
SummaryExtraordinary result Indirect measurement
Contradicts theorySpecial and general relativity
Contradicts experimentParticle experimentsAstronomy experiments
Extraordinary evidence? X
Explanation ?
The verdict
Unreliable resultRe-runs possible but not beneficial
• Reproducible?Many checks carried out
• Technical flaw discoveredCable to external GPS clock Accounts for time discrepancy
• A second flawInternal clock
We told you so
Lessons to be learnt
1. Unexpected result? Check, check, check Emphasis on simple errors
2. Do not publish If in conflict with theory and experiment
3. Do not underestimate the media ‘Einstein wrong’ is a huge story
Further reading: ANTIMATTER
Relativity and GPS
• Signal from satellite
compare time received to transmitted
synchronized clocks
• Convert time to distance
x speed of radiowaves
Assumes constancy of speed of light
• Triangulation using 4 sources accurate to within 5 metres
GPS: a relativistic correction
• Motion of satellite (SR)
Clocks slow by 7 μs/day
• Reduced gravity field (GR)
Clocks fast by 45 μs/day
Satellite clocks fast by 38 μs/ day
Well-known correction to GPS OPERA - new correction? (18m?)
Synchronization of satellite/earth clocks
What if result stands?
First evidence of string theory ?
• Extra dimensionsShortcut?
Doesn’t violate relativity
• Unified field theory 7 dimensions curled up?
• High energy Lightest particlesDoesn’t contradict previous results
Further reading: ANTIMATTER
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