the big bang, the lhc and the god particle cormac o’raifeartaigh (wit) faster than the speed of...

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 experiment

What, why, how

II Relativity (special)

Theory and experiment

III Relativity (general)

Theory and experiment

IV Skepticism in science Coda: what if..?

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 in vacuum!

Highly respected group

Neutrinos

• Suggested by Pauli (1930)

• Conservation of energy

• Zero charge, ‘zero’ mass

• Weak interaction

• Skepticism (non-physicists)

Detected in 1956

Neutrinos

• Tiny mass (non-zero?)

• Dark matter? • The solar neutrino paradox

• Gran Sasso experiment

Three different types Neutrino oscillation

Change of flavour

Standard Model

neutrino = lighter cousin of electron

The OPERA experiment

OPERA: the numbers

Measurement of distance (GPS)

732 km +/- 20 cm

• Time of flight +/- 10ns

2.43006 +/- 0.00001 ms

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 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

Time dilation: muons

v = 3 x 108 m/s

t = 2.2 x 10-6 s (lifetime)

d = 660m

Moving clocks run slow

Many muons detected at ground level d = 10 km ?

Muons created in upper atmosphere

Vampire muon

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

Compare: evolution, climate science

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• Revolution• Cosmological implications Matter warps space and time

General Relativity (1915)

General relativity (experiment)

Predictions• Bending of starlight by sun• Black holes• Expanding universe• Geodesic effect• Time dilation by gravity

Evidence• Eddington experiment• Astronomy • Cosmology (big bang)• Everett experiment • GPS

Breakdown at quantum scales

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

Skepticism from astronomy

Supernova• Huge implosion of massive star• Neutrinos released• Light delayed

Supernova 1987a• Neutrinos detected• Ahead of light by 3 hours

Not by 5 years !

IV Skepticism in science

Many years for new result to be accepted

Must be reproducible

Must fit known experiments

• Paradigm shift• Slow, gradual process (DJ)• Consensus process

If so

Compare: accelerating universe

Thomas Kuhn

The OPERA viewpoint

‘Despite the large significance of the measurement reported here and the stability of the analysis, the potentially great impact of the result motivates the continuation of our studies in order to investigate possible still unknown systematic effects that could explain the observed anomaly. We deliberately do not attempt any theoretical or phenomenological interpretation of the results’ ‘Up to half of the members of the OPERA project are opposed to immediately publishing the result in a peer-reviewed journal. They do not believe any known mistakes are being hidden by other members of the group, but are worried about the significant impact to physics of the results.’ Physics World

Science in the media

Scientific skepticism misunderstood

Attributed to conservatism

Role of evidence misunderstood

‘Balanced’ debate unweighted

Climate ‘skepticism’ is not scientific

Science journalism: news driven Bjorn Lomborg

SummaryExtraordinary result Indirect measurement

Contradicts theorySpecial and general relativity

Contradicts experimentParticle experimentsAstronomy experiments

Extraordinary evidence? X

But what if.... ?

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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