Dan Hooper

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Theoretical Particle-Astrophysics At Fermilab

• Dan Hooper
• Theoretical Astrophysics Group
• Fermi National Laboratory
• dhooper_at_fnal.gov

Annual DOE Review May 17, 2006
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How To Study Particle Physics?

• Traditionally, particle physics has been studied
  using collider experiments
• Incredibly high luminosity beams very large
  numbers of collisions can be observed
• Energy is technology/cost limited
• Tevatron (1.96 TeV)
• LHC (14 TeV)

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How To Study Particle Physics?

• Astrophysical accelerators are known to
  accelerate particles to at least 1020 eV
  (center-of-mass energies of hundreds of TeV)
• Opportunities to study stable or extremely long
  lived particles (neutralinos, or other WIMPs,
  axions, topological defects, etc.)
• Extremely long baseline
• measurement possible
• Provides a natural complementarity with
  collider experiments

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Activity in Theoretical Particle-Astrophysics at
Fermilab

• Particle Dark Matter
• High Energy Cosmic Ray and Neutrino Physics
• Early Universe Particle Cosmology
  (lepto/baryogenesis, BBN,)

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Activity in Theoretical Particle-Astrophysics at
Fermilab

• Particle Dark Matter
• High Energy Cosmic Ray and Neutrino Physics
• Early Universe Particle Cosmology
  (lepto/baryogenesis, BBN,)

CDMS
Pierre Auger Observatory
Minos, MiniBooNE
Tevatron
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Activity in Theoretical Particle-Astrophysics at
Fermilab

• Particle Dark Matter
• High Energy Cosmic Ray and Neutrino Physics
• Early Universe Particle Cosmology
  (lepto/baryogenesis, BBN,)
• Physics Beyond the Standard Model (SUSY, extra
  dimensions,)

CDMS
Pierre Auger Observatory
Minos, MiniBooNE
Tevatron
Particle Theory Group
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Particle Dark Matter

• M. Carena, DH, P. Skands, Implications of direct
  dark matter searches for MSSM Higgs searches at
  the Tevatron (hep-ph/0603180)
• G. Zaharijas, DH, Challenges in Detecting
  Gamma-Rays From Dark Matter Annihilations in the
  Galactic Center (accepted by PRD,
  astro-ph/0603540)
• G. Bertone, A. Zenter, J. Silk, A new signature
  of dark matter annihilations gamma-rays from
  intermediate-mass black holes (PRD,
  astro-ph/0509565)
• P. Fayet, DH, G. Sigl, Constraints on light dark
  matter from core-collapse supernovae
  (hep-ph/0602169)
• L. Bergstrom, DH, Dark matter and gamma-rays from
  Draco MAGIC, GLAST and CACTUS (PRD,
  hep-ph/0512317)
• F. Halzen, DH, Prospects for detecting dark
  matter with neutrino telescopes in light of
  recent results from direct detection experiments
  (PRD, hep-ph/0509352)
• T. Flacke, DH, J. March-Russell, Improved bounds
  on universal extra dimensions and consequences
  for LKP dark matter (PRD, hep-ph/0509352)
• J. Gunion, DH, B. McElrath, Light neutralino dark
  matter in the NMSSM (PRD, hep-ph/0509024)

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Particle Dark Matter

• How Do We Detect Dark Matter?
• Numerous methods of direct and indirect
  detection are being explored vast room for
  theoretical activity

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Particle Dark Matter

• How Do We Detect Dark Matter?
• Gamma-ray telescopes can potentially discover
  dark matter by observing annihilation radiation
  (Hess, Magic, Veritas, Glast)
• The center of our galaxy has long been considered
  the most likely region to generate such a signal
• Recently, four gamma-ray telescopes have detected
  TeV emission from the galactic center

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Particle Dark Matter

• How Do We Detect Dark Matter?
• The spectrum measured from the galactic center
  extends to at least 10 TeV, and appears to
  not fit the prediction of annihilating dark
  matter
• Presence of new astrophysical source greatly
  reduces prospects for dark matter detection with
  planned experiments

Excluded by HESS
Excluded by EGRET
Undetectable by GLAST
(G. Zaharijas and DH, 2006)
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Particle Dark Matter

• How Do We Detect Dark Matter?
• The spectrum measured from the galactic center
  extends to at least 10 TeV, and appears to
  not fit the prediction of annihilating dark
  matter
• Presence of new astrophysical source greatly
  reduces prospects for dark matter detection with
  planned experiments
• Look to other sources of potentially observable
  dark matter annihilation radiation
• -Dwarf Spheriodal Galaxies (L.
  Bergstrom and DH, 2005)
• -Intermediate mass galactic black holes
  (G. Bertone, Zentner, Silk, 2005)

Dark Matter Radiation From 100 IMBHs May Be
Observable
(Bertone, Zentner, Silk, 2005)
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Particle Dark Matter

• How Do We Detect It?
• What Will A Detection Reveal To Us?
• There is a big difference between measuring rates
  in dark matter experiments and identifying the
  particle nature of a WIMP
• Can various models be discriminated from
  astrophysical observables? Could SUSY parameters
  be constrained, or measured?
• Much more theoretical work is needed to make the
  most out of any future detection/discovery

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Particle Dark Matter

• What Will A Detection Reveal To Us?
• The direct detection (neutralino-nuclei elastic
  scattering) rate provides information on
  neutralino composition, mA, and tan ?

(Carena, DH, Skands, 2006 DH, A. Taylor, 2006)
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Particle Dark Matter

• What Will A Detection Reveal To Us?
• The direct detection (neutralino-nuclei elastic
  scattering) rate provides information on
  neutralino composition, mA, and tan ?
• Rates in neutrino telescopes depend on
  spin-dependent scattering cross section with
  protons (higgsino composition)

(DH, A. Taylor, 2006)
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Particle Dark Matter

• What Will A Detection Reveal To Us?
• The direct detection (neutralino-nuclei elastic
  scattering) rate provides information on
  neutralino composition, mA, and tan ?
• Rates in neutrino telescopes depend on
  spin-dependent scattering cross section with
  protons (higgsino composition)
• Combining these and other astrophysical inputs
  can (in many models) allow for a determination of
  parameters such as ? or tan ?, beyond that which
  can be made at the Tevatron or LHC

LHCRelic Density
Actual Value
CDMS
(DH, A. Taylor, 2006)
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Particle Dark Matter

• What Will A Detection Reveal To Us?

Much Work Remains To Be Done
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Ultra-High Energy Particle-Astro Physics

• E.J. Ahn, M. Cavaglia, Simulations of black hole
  air showers in cosmic ray detectors (PRD,
  hep-ph/0511159)
• L. Anchordoqui, T. Han, DH, S. Sarkar, Exotic
  neutrino interactions at the Pierre Auger
  Observatory (Astropart. Phys, hep-ph/0508312)
• N. Busca, DH, E. Kolb, Pierre auger data,
  photons, and top-down cosmic ray models
  (astro-ph/0603055)
• F. Halzen, DH, A limit on the ultra-high energy
  neutrino flux from AMANDA (astro-ph/0605XXX)

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Ultra-High Energy Particle-Astro Physics

• What is the origin of the Ultra-High Energy
  Cosmic Rays?
• Extremely high energy cosmic ray events
  (super-GZK) may imply the existence of local
  sources (AGN, GRB, etc.), or of new physics
• No local astrophysical sources are known
• New physics proposals have included top-down
  models (ie. WIMPzillas!) and new
  exotic particles or interactions (ie. strongly
  interacting neutrinos)
• Neutrino and gamma-ray observations, in addition
  to further cosmic ray data (Pierre Auger
  Observatory) will likely be needed to resolve
  this question

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Ultra-High Energy Particle-Astro Physics

• Searching for Ultra-High Energy Neutrinos
• Current limits on UHE neutrinos are only a factor
  of 5 below standard predictions

(F. Halzen, DH, 2006)
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Ultra-High Energy Particle-Astro Physics

• Searching for Ultra-High Energy Neutrinos
• Numerous techniques are approaching the level of
  sensitivity needed to observe UHE neutrinos
  (AMANDA/IceCube, RICE, Auger, ANITA)
• The First Ultra-High Energy Neutrino
  Detection is Imminent!

(F. Halzen, DH, 2006)
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Ultra-High Energy Particle-Astro Physics

• What is the origin of the Ultra-High Energy
  Cosmic Rays?
• What fundamental physics can be probed with
  Cosmic Ultra-High Energy Particles?
• Extremely high energy collisions-beyond the reach
  of colliders
• Wide range of exotic physics scenarios can be
  tested

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Ultra-High Energy Particle-Astro Physics

• Fundamental Physics with Ultra-High Energy
  Neutrinos
• Neutrino-nucleon cross section measurements
  possible at Auger, IceCube (downgoing rate to
  rate through Earth)
• TeV-scale gravity, SM electroweak instantons,
  R-parity violating SUSY models

Microscopic Black Hole Production
Earth-Skimming Rate Suppressed
Downgoing Rate Enhanced
(Anchordoqui, Han, DH, Sarkar, Astropart.Phys.,
2005)
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Summary and Conclusions

• Research in particle dark matter, ultra-high
  energy cosmic rays, high-energy neutrinos, and
  other areas of particle-astrophysics are very
  active and exciting at Fermilab
• Interaction with experimental groups (CDMS,
  Pierre Auger) and particle theory group make
  Fermilab an excellent place to study this
  multi-disciplinary science

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Particle-Astrophysics
A Multi-Disciplinary Science

• Strong interactions with particle theory group
  (joint pizza meetings/seminars) and
  experimentalists (munch, astro-coffee)
• Two new postdocs strong in multiple fields to be
  joining our group this fall (Pasquale Serpico,
  Jason Steffen)

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THANK YOU