Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos Dan
- Slides: 26
Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos Dan Hooper Particle Astrophysics Center Fermi National Accelerator Laboratory dhooper@fnal. gov Aspen Workshop on Cosmic Rays April 2007
The Origin of the Highest Energy Cosmic Rays • The cosmic ray spectrum has been measured to extend to at least ~1020 e. V • The origin of these extremely high energy particles remains unknown • Attenuation of UHECRs by the CMB (the GZK cutoff) requires sources within ~10 -100 Mpc • Few astrophysical accelerators potentially capable to producing such high energy events - none are known within the GZK radius Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
The Composition of the Highest Energy Cosmic Rays • Current observations are unable to determine whether the UHECR spectrum is dominated by protons or nuclei Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
The Composition of the Highest Energy Cosmic Rays • There are, however, a number of arguments favoring nuclei: -CR data can be interpreted as marginally favoring significant nuclei composition -Magnetic fields effect nuclei more strongly, helping to explain the lack of identified UHECR point sources -Hillas criterion for maximum energy produced in a cosmic ray accelerator scales with electric charge, Z Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
The Composition of the Highest Energy Cosmic Rays • There are, however, a number of arguments favoring nuclei: -CR data can be interpreted as marginally favoring significant nuclei composition -Magnetic fields effect nuclei more strongly, helping to explain the lack of identified UHECR point sources -Hillas criterion for maximum energy produced in a cosmic ray accelerator scales with electric charge, Z The composition of the UHECR spectrum has significant implications for neutrino astronomy Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
Protons as UHE Cosmic Rays Protons interact with CMB photons through several channels: • Catastrophic processes above ~1019. 5 e. V: p + CMB p + 0 , n + +, and multi-pion production • Continuous energy losses from p + CMB p + e+ + e- Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
Nuclei as UHE Cosmic Rays • Nuclei undergo photodisintegration via interactions with CMB and CIRB photons: ie. Fe 56 Mn 55 + p, Mn 55 Mn 54 + n, etc. • Leads to energy loss rates comparable to UHE protons Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos Hooper, S. Sarkar, A. Taylor, Astropart. Phys. , astro-ph/0608085
Nuclei as UHE Cosmic Rays • Leads to a mixed cosmic ray composition (various nuclei species plus protons) at Earth, which varies with energy Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos Hooper, S. Sarkar, A. Taylor, Astropart. Phys. , astro-ph/0608085
Cosmogenic Neutrinos • In either case (protons or nuclei UHECRs) UHE neutrinos are produced as a biproduct of cosmic ray propagation • For example: p e e p + CMB n + + e Fe 56 + CMB/CIRB Mn 55 + p Neutrinos! Mn 55 + CMB/CIRB Mn 54 + n … etc. Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos p e e
Cosmogenic Neutrinos • Proton cosmic rays generate a two-component cosmogenic neutrino spectrum • Often thought of as a guaranteed flux of UHE neutrinos Neutron Decay Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos Pion Decay
Cosmogenic Neutrinos • Anticipated to generate a potentially observable rate of UHE neutrinos in several near future experiments, including Ice. Cube, Anita, Rice, and the Pierre Auger Observatory Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
Tools of the Trade: Ice. Cube • Successor to AMANDA • Full Cubic Kilometer Instrumented Volume • 22 (of 80) strings currently deployed (13 this season) Sensitive to: Muon tracks (above ~100 Ge. V), EM/hadronic showers (above a few Te. V), Tau-unique events (above ~1 Pe. V) Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
Tools of the Trade: Radio Techniques RICE • Array of radio antennas co-deployed with AMANDA • Effective Volume of ~1 km 3 at 100 Pe. V; several km 3 at 10 Ee. V • Limits on diffuse neutrino flux in 200 Pe. V-200 Ee. V range of 6 x 10 -7 Ge. V cm-2 s-1 sr-1 • Radio codeployments with Ice. Cube promising ANITA • Balloon-based radio antennas • ANITA-lite limit on diffuse flux above ~Ee. V of ~10 -6 Ge. V/cm 2 s 1 sr 1 • 36 day ANITA flight ended Jan. 20 sensitivity of ~10 -8 Ge. V/cm 2 s sr observe the first UHE neutrino? Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
UHECR Experiments as Neutrino Detectors The Pierre Auger Observatory • Southern cite currently under construction in Argentina • First data released in 2005 (no neutrino data yet) • Sensitive above 108 Ge. V, 3000 km 2 surface area • Neutrino ID possible for quasi-horizontal showers and Earth-skimming, tau-induced showers • AGASA experiment places limits on UHE neutrino fluxes EUSO/OWL • Satellite/space station based • Enormous aperture • Future uncertain Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
Cosmogenic Neutrinos • Although their peak sensitivity lies at different energies, Ice. Cube, Anita and Auger each anticipate ~1 event per year (or per flight) for a standard (proton) cosmogenic neutrino flux Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos F. Halzen and Hooper, PRL, astro-ph/0605103
Cosmic Ray Nuclei and Cosmogenic Neutrinos • In the case of a cosmic ray spectrum dominated by heavy nuclei, however, the pion decay component of the cosmogenic neutrino flux is reduced protons He O Fe Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos Hooper, S. Sarkar, A. Taylor, Astropart. Phys. , astro-ph/0407618
Cosmic Ray Nuclei and Cosmogenic Neutrinos • The degree of suppression depends critically on the maximum energy to which cosmic rays are accelerated Fe 56 + CMB Mn 55 + p Fe, Emax=1022. 5 Emax=1021. 5 Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos In order to contribute to the cosmogenic neutrino flux, photodisassociated protons must exceed the GZK cutoff, thus the original nuclei must exceed EGZK x A Hooper, S. Sarkar, A. Taylor, Astropart. Phys. , astro-ph/0407618
Extragalactic Sources of High Energy Neutrinos • Cosmic ray spectrum of protons/nuclei extends to ~1020 e. V • pp, p interactions generate neutrinos from cosmic ray sources Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
Extragalactic Sources of High Energy Neutrinos • Cosmic ray spectrum of protons/nuclei extends to ~1020 e. V • pp, p interactions generate neutrinos from cosmic ray sources • The flux of neutrinos produced in UHE/HE sources can be tied to the cosmic ray spectrum • “Waxman-Bahcall” Argument: Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
Extragalactic Sources of High Energy Neutrinos • Cosmic ray spectrum of protons/nuclei extends to ~1020 e. V • pp, p interactions generate neutrinos from cosmic ray sources • The flux of neutrinos produced in UHE/HE sources can be tied to the cosmic ray spectrum • “Waxman-Bahcall” Argument: Fraction of proton energy to pions Accounts for source evolution, etc. (~1) Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos
The Extragalactic Neutrino Flux • Ice. Cube will reach well below the predicted levels for ~ 1 the Waxman-Bahcall “Flux”) • Models of gamma ray bursts, active galactic nuclei, and starburst galaxies each predict a flux of neutrinos within the reach of Ice. Cube (3 yrs) Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos (ie.
The Extragalactic Neutrino Flux • Ice. Cube will reach well below the predicted levels for ~ 1 the Waxman-Bahcall “Flux”) • Models of gamma ray bursts, active galactic nuclei, and starburst galaxies each predict a flux of neutrinos within the reach of Ice. Cube Likely to observe first cosmic high-energy neutrinos in coming years Ice. Cube (3 yrs) Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos (ie.
The Extragalactic Neutrino Flux • Ice. Cube will reach well below the predicted levels for ~ 1 the Waxman-Bahcall “Flux”) • Models of gamma ray bursts, active galactic nuclei, and starburst galaxies each predict a flux of neutrinos within the reach of Ice. Cube Likely to observe first cosmic high-energy neutrinos in coming years Likely to be more difficult if the bulk of the UHECR spectrum consists of nuclei Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos Ice. Cube (3 yrs) (ie.
Nuclei and the Extragalactic Neutrino Flux • Different classes of comic ray sources are expected to photodisintegrate accelerated nuclei to varying degrees • In the fully disintegrated limit, Waxman-Bahcall prediction is restored • Lesser disintegration reduces the expected neutrino flux Dan Hooper - Ultrahigh Energy Cosmic Ray Nuclei and Neutrinos L. Anchordoqui, Hooper, S. Sarkar, A. Taylor, astro-ph/0703001
Nuclei and the Extragalactic Neutrino Flux • Above ~100 Te. V, GRB neutrino spectrum is largely unchanged (overall rate reduced by ~20%) • For AGN, neutrino flux is reduced considerably (overall rate reduced by ~80%) Dan Hooper - Ultrahigh Energy Anchordoqui, Hooper, Sarkar, Taylor, astro-ph/0703001 Cosmic Ray Nuclei and Neutrinos
Summary • Composition of the highest energy cosmic rays is still an open question, with important implications for neutrino astronomy • The presence of heavy or intermediate mass nuclei in the UHECR spectrum can substantially reduce the expected cosmogenic neutrino flux • Nuclei accelerated in cosmic ray sources (AGN, GRB, etc. ) can result in a reduced estimate for the neutrino flux as compared to the all-proton case • As the first experiments reach the sensitivity needed to observe HE/UHE neutrinos (Anita, Ice. Cube, Auger, etc. ), the composition of the cosmic ray spectrum is also being indirectly probed
- Neutrinos
- Neutrinos
- Neutrinos
- Cosmic ray showers
- Cosmic ray elab
- Coracu
- Bit flip cosmic ray
- Cosmic ray
- Cosmic ray spectrum
- Cosmic ray
- Cosmic ray
- Sin and cos in quadrants
- Ray casting algorithm
- Ray model of light
- Energy energy transfer and general energy analysis
- Energy energy transfer and general energy analysis
- Cosmic rays and clouds
- Dual energy x ray absorptiometry (dexa)
- Osteoporosis t score
- Hair dryer sankey diagram
- Bid rent theory example
- Multiple nuclei model cons
- Multiple nuclei model criticisms
- Harris and ullman model
- What is the concentric zone model
- Urban realms model
- Nmr active and inactive nuclei