Dan HooperTheoretical Astrophysics Group

Fermi National Laboratorydhooper@fnal.gov

Theoretical Particle-Astrophysics Theoretical Particle-Astrophysics At FermilabAt Fermilab

Annual DOE ReviewMay 17, 2006

How To Study Particle Physics?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)

How To Study Particle Physics?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

Activity in Theoretical Particle-Astrophysics Activity in Theoretical Particle-Astrophysics at Fermilabat Fermilab

•Particle Dark Matter

•High Energy Cosmic Ray and Neutrino Physics

•Early Universe Particle Cosmology (lepto/baryogenesis, BBN,…)

Activity in Theoretical Particle-Astrophysics Activity in Theoretical Particle-Astrophysics at Fermilabat Fermilab

•Particle Dark Matter

•High Energy Cosmic Ray and Neutrino Physics

•Early Universe Particle Cosmology (lepto/baryogenesis, BBN,…)

CDMSPierre Auger Observatory

Minos, MiniBooNE

Tevatron

Activity in Theoretical Particle-Astrophysics Activity in Theoretical Particle-Astrophysics at Fermilabat 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,…)

CDMSPierre Auger Observatory

Minos, MiniBooNE

Tevatron

Particle Theory Group

Particle Dark MatterParticle 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)

Particle Dark MatterParticle Dark Matter

1. How Do We Detect Dark Matter?

Numerous methods of direct and indirect detection are being

explored; vast room for theoretical activity

Particle Dark MatterParticle Dark Matter

1. 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

Particle Dark MatterParticle Dark Matter

1. 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

Undetectable by GLAST

Excluded by EGRETExcluded by HESS

(G. Zaharijas and DH, 2006)

Particle Dark MatterParticle Dark Matter

1. 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)

(Bertone, Zentner, Silk, 2005)

Dark Matter Radiation From ~100 IMBHs May Be Observable

Particle Dark MatterParticle Dark Matter

1. How Do We Detect It? 2. 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

Particle Dark MatterParticle 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)

Particle Dark MatterParticle 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)

Particle Dark MatterParticle 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

LHC+Relic Density

+ CDMS

Actual Value

(DH, A. Taylor, 2006)

Particle Dark MatterParticle Dark Matter

What Will A Detection Reveal To Us?

Much Work Remains To Be Done

Ultra-High Energy Particle-Astro PhysicsUltra-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)

Ultra-High Energy Particle-Astro PhysicsUltra-High Energy Particle-Astro Physics

1. 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

Ultra-High Energy Particle-Astro PhysicsUltra-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)

Ultra-High Energy Particle-Astro PhysicsUltra-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)

Ultra-High Energy Particle-Astro PhysicsUltra-High Energy Particle-Astro Physics

1. What is the origin of the Ultra-High Energy Cosmic Rays?2. 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

Ultra-High Energy Particle-Astro PhysicsUltra-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

(Anchordoqui, Han, DH, Sarkar, Astropart.Phys., 2005)

Microscopic Black Hole Production

Earth-Skimming Rate Suppressed

Downgoing Rate Enhanced

Summary and ConclusionsSummary 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

Particle-Astrophysics: A Particle-Astrophysics: A Multi-Disciplinary ScienceMulti-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)

THANK YOUTHANK YOU