Transcript Faster than the speed of light Was Einstein wrong? The Big Bang, the LHC and the God Particle Cormac O’Raifeartaigh (WIT) Cormac O’Raifeartaigh (WIT)

```Faster than the speed of light
Was Einstein wrong?
The Big Bang, the LHC and the God
Particle
Cormac O’Raifeartaigh (WIT)
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
Beam of neutrinos at CERN
Detector under Gran Sasso
Distance of 732 km
Time of flight 2.43 ms
0.003% faster than light !
Result: early by 60 nanoseconds
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
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/time
Need 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
Implications for bodies at high speed
Length contraction
L(v )  L0 1  v 2 / c 2
Time dilation
t (v )  t 0 / 1  v 2 / c 2
Mass increase
m(v)  m0 / 1  v 2 / c 2
E = mc2
Evidence for relativity
Early experiments
Kaufmann, Bucherer
Particle accelerators
Length contraction
Time dilation
Mass increase
Modern particle accelerators
Speed limit
Particle creation
E = mc2
CERN (Geneva)
• energy increase
• velocity increase?
K.E = 1/2mv2
mass increases
m(v)  m0 / 1  v 2 / c 2
Relativity ‘skepticism’
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Extraordinary concept
Counter-intuitive
Only observable at tremendous speeds
Only observable for subatomic particles
Speed of light plays role of infinity
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Simple maths
Time and distance calculations
Personalization
Confusion of discovery and justification
Dr Al Kelly
‘Einstein wrong’
III The general theory of relativity
General Relativity (1915)
• Laws of physics identical for all observers
• Speed of light in vacuum a universal constant
• Principle of equivalence
Gravity = curvature of space and time
• New view of gravity
• Cosmological implications
Matter warps space and time
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
If so
• Consensus process
Compare: accelerating universe
Thomas Kuhn
Skepticism in the media
Scientific skepticism misunderstood
Attributed to conservatism
Role of evidence misunderstood
‘Balanced’ debate unweighted
Bjorn Lomborg
Science journalism: news driven
Summary
Extraordinary result
Indirect measurement
Special and general relativity
Particle experiments
Astronomy experiments
Extraordinary evidence? X
Explanation ?
The verdict
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Reproducible?
Many checks carried out
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Technical flaw discovered
Cable to external GPS clock
Accounts for time discrepancy
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A second flaw
Internal clock
Unreliable result
Re-runs possible but not beneficial
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
Relativity and GPS
• Signal from satellite
synchronized clocks
• Convert time to distance
• Triangulation using 4 sources
accurate to within 5 metres
Assumes constancy of speed of light
GPS: a relativistic correction
Synchronization of satellite/earth clocks
• 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?)
What if result stands?
Extra dimensions
Shortcut?
Doesn’t violate relativity
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Unified field theory
7 dimensions curled up?
High energy
Lightest particles