Coupled Boltzmann calculation of mixed axion/neutralino cold dark matter production in the early universe

Journal of Cosmology and Astroparticle Physics (Impact Factor: 6.04). 10/2011; 2012(01). DOI: 10.1088/1475-7516/2012/01/036
Source: arXiv

ABSTRACT We calculate the relic abundance of mixed axion/neutralino cold dark matter
which arises in R-parity conserving supersymmetric (SUSY) models wherein the
strong CP problem is solved by the Peccei-Quinn (PQ) mechanism with a
concommitant axion/saxion/axino supermultiplet. By numerically solving the
coupled Boltzmann equations, we include the combined effects of 1. thermal
axino production with cascade decays to a neutralino LSP, 2. thermal saxion
production and production via coherent oscillations along with cascade decays
and entropy injection, 3. thermal neutralino production and re-annihilation
after both axino and saxion decays, 4. gravitino production and decay and 5.
axion production both thermally and via oscillations. For SUSY models with too
high a standard neutralino thermal abundance, we find the combined effect of
SUSY PQ particles is not enough to lower the neutralino abundance down to its
measured value, while at the same time respecting bounds on late-decaying
neutral particles from BBN. However, models with a standard neutralino
underabundance can now be allowed with either neutralino or axion domination of
dark matter, and furthermore, these models can allow the PQ breaking scale f_a
to be pushed up into the 10^{14}-10^{15} GeV range, which is where it is
typically expected to be in string theory models.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We re-evaluate prospects for supersymmetry at the proposed International Linear $e^+e^-$ Collider (ILC) in light of the first year of serious data taking at LHC with $\sqrt{s}=7$ TeV and $\sim 5$ fb$^{-1}$ of $pp$ collisions (LHC7). Strong new limits from LHC SUSY searches, along with a hint of a Higgs boson signal around $m_h\sim 125$ GeV, suggest a paradigm shift from previously popular models to ones with new and compelling signatures. We present a variety of new ILC benchmark models, including: natural SUSY, hidden SUSY, NUHM2 with low $m_A$, non-universal gaugino mass (NUGM) model, pMSSM, Kallosh-Linde model, Br\"ummer-Buchm\"uller model, normal scalar mass hierarchy (NMH) plus one surviving case from mSUGRA/CMSSM in the far focus point region. While all these models at present elude the latest LHC limits, they do offer intriguing case study possibilities for ILC operating at $\sqrt{s}\sim 0.25-1$ TeV, and present a view of some of the diverse SUSY phenomena which might be expected at both LHC and ILC in the post LHC7 era.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be about 4-5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few $\times 10^{-12}$ GeV$^{-1}$ and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive to solar axions produced by mechanisms mediated by the axion-electron coupling $g_{ae}$ with sensitivity $-$for the first time$-$ to values of $g_{ae}$ not previously excluded by astrophysics. With several other possible physics cases, IAXO has the potential to serve as a multi-purpose facility for generic axion and ALP research in the next decade. In this paper we present the conceptual design of IAXO, which follows the layout of an enhanced axion helioscope, based on a purpose-built 20m-long 8-coils toroidal superconducting magnet. All the eight 60cm-diameter magnet bores are equipped with focusing x-ray optics, able to focus the signal photons into $\sim 0.2$ cm$^2$ spots that are imaged by ultra-low-background Micromegas x-ray detectors. The magnet is built into a structure with elevation and azimuth drives that will allow for solar tracking for $\sim$12 h each day.
    Journal of Instrumentation 01/2014; 9(05). · 1.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this Report we discuss the four complementary searches for the identity of dark matter: direct detection experiments that look for dark matter interacting in the lab, indirect detection experiments that connect lab signals to dark matter in our own and other galaxies, collider experiments that elucidate the particle properties of dark matter, and astrophysical probes sensitive to non-gravitational interactions of dark matter. The complementarity among the different dark matter searches is discussed qualitatively and illustrated quantitatively in several theoretical scenarios. Our primary conclusion is that the diversity of possible dark matter candidates requires a balanced program based on all four of those approaches.


1 Download
Available from