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Andreas Ringwald, DESY
27th DESY PRC Closed Session, DESY, Hamburg, 26 October 2011
Towards a comprehensive summary
Physics Case for WISP Searches.
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 2
Summary of Physics Case
> Very Weakly Interacting Slim Particles (WISPs) are strongly motivated from theory, cosmology, and astrophysics
Theory:
AxionsAxion-Like Particles (ALPs)hidden sector U(1)s (HPs)
Cosmology:
Axion, ALP, or HP Cold Dark Matter (CDM)
Extra, dark radiation during CMB decoupling
Astrophysics:
Photon ALP oscillations as explanation of anomalous transparency of the universe for TeV gamma rays
Axion or ALP bremsstrahlung as explanation of non-standard energy loss of white dwarfs
> ALPS II can search for them in strongly motivated parameter region
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 3
WISPy Cold Dark Matter
> Axions, ALPs and HPs can be born in the early universe non-thermally in the form of spatially homogeneous classical field oscillations (misalignment mechanism)
> If sufficiently weakly coupled, this CDM component survives until today
Arias, Cadamuro, Goodsell, Jaeckel, Redondo, AR, in prep.
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WISPy Cold Dark Matter
> ALPS II 2012 will reach the parameter range of interest for HP CDM:
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 5
WISPy Cold Dark Matter
> ALPS II 2017 will reach the parameter range of interest for ALP CDM:
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HP Dark Radiation
>Global fit to CMB angular power spectrum slightly prefers extra dark radiation beyond three light neutrinos:
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 7
HP Dark Radiation
>Global fit to CMB angular power spectrum slightly prefers extra dark radiation beyond three light neutrinos:
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 8
HP Dark Radiation
> For meV scale masses, photon -> HP conversions occur resonantly after BBN, but before CMB decoupling -> HP dark radiation
Jaeckel, Redondo, AR
> ALPS II 2012 can probe HP explanation of extra dark radiation:
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Light Shining through Cosmic Walls
> Spectra of distant VHE gamma-ray sources show no strong indications of absorption features due to pair production processes from scattering off photon bath in intergalactic space (Extragalactic Background Light)
Horns, Meyer, subm. to JCAP
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Light Shining through Cosmic Walls
> Photon -> ALP conversions in cosmic magnetic fields may explain this observation, for ALP masses below neV and g ~ 10e-11/GeV
De Angelis, Roncadelli, Mansutti; …; Simet, Hooper, Serpico; …; Hochmuth, Sigl; …;Mirizzi, Montanino
M
Meyer
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 11
Light Shining through Cosmic Walls
> Photon -> ALP conversions in cosmic magnetic fields may explain this observation, for ALP masses below neV and g ~ 10e-11/GeV
De Angelis, Roncadelli, Mansutti; …; Simet, Hooper, Serpico; …; Hochmuth, Sigl; …;Mirizzi, Montanino
Meyer
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 12
Non-Standard Energy Loss in White Dwarfs
> Standard model does not fit to white dwarf luminosity function
> Extra energy loss compatible with axion or ALP bremsstrahlung (mass below keV, decay constant ~ 1e9 GeV -> g ~ 1e-11/GeV)
Isern et al.
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Andreas Ringwald | Physics Case for WISP Searches | 26 October 2011 | Page 13
Physics Reach of ALPS II 2017
> ALPS II 2017 will reach the parameter range of interest for VHE light shining through the EBL and WD energy loss (g ~ 10e-11/GeV ):