Pre-LHC Expectations and Media Coverage (2008-2010)

• Particle physicists had high hopes LHC would find new particles beyond Higgs boson
• Expected discoveries included:
  • Dark matter particles
  • Supersymmetry particles
  • Dark energy connections
  • Additional dimensions of space
  • String balls, black holes
  • Time travel possibilities
  • Contact with parallel universes
  • "Unparticles" (particles that aren't particles)

Media Quotes from 2008-2010

• Valerie Jamison (New Scientist, 2008): Predicted external dimensions, mini black holes, new forces, particles smaller than quarks/electrons, time-travel tests
• Ian Sample (The Guardian, 2008): Expected never-seen-before particles, hidden dimensions, dark matter (25% of universe)
• Polling Occur (APS, 2010): Predicted spectacular supersymmetry signals visible at LHC
• Michael Dine (Physics Today, 2010): LHC would either make spectacular discovery or rule out supersymmetry entirely
• The Telegraph (2010): Could reveal 5th, 6th, or 7th secret dimensions of time/space
• Steve Gearing (2010): Expected dark matter particles, dark energy insights, extra dimensions, microscopic black holes, supersymmetry discovery

LHC Results Since 2010

• LHC has been running since 2010
• Successfully found Higgs boson
• Failed to find any other predicted phenomena
• No supersymmetry, extra dimensions, dark matter particles, etc.

Why Predictions Failed - Fundamental Difference

• Higgs prediction was necessary: Standard model without Higgs mathematically inconsistent
  • Predicts probabilities >1 (impossible)
  • Breaks down at LHC-reachable energies
  • Something new HAD to happen
• Other predictions were unnecessary: Compatible with observations but not required to solve problems
• All other theories described as "wishful thinking"

Technical Naturalness Problem

• Many physicists believed standard model had additional problem Higgs wouldn't fix
• Problem: Standard model "not technically natural"
• Contains small unexplained number: Higgs mass/Planck mass ≈ 10^-15
• Number works fine, fits data, but considered "ugly" without explanation
• Physicists didn't want to believe nature could be "ugly"
• Reality: Nature doesn't care what physicists want

Implications for Future Particle Physics

• Technical naturalness was only reason to expect standard model incomplete at LHC energies
• Argument proven wrong - no reason for next collider to find anything new
• Standard model runs into trouble again at energies ~billion times higher than next collider could test
• No good reason to build larger particle collider

Predicted Research Shifts

• Away from collider physics (shift ongoing ~2 decades, will accelerate)
• Toward astrophysics: Dark matter and dark energy studies, early universe research
• Toward high-precision measurements: Lower energy experiments, tabletop quantum experiments
• Focus on many-particle quantum systems where much remains unknown