Neutrinos from WIMP annihilation in the Sun : Implications of a self-consistent model of the Milky Way's dark matter halo

Physical review D: Particles and fields 06/2011; DOI: 10.1103/PhysRevD.85.123533
Source: arXiv

ABSTRACT Upper limits on the spin-independent (SI) as well as spin-dependent (SD)
elastic scattering cross sections of WIMPs with protons, imposed by the
Super-Kamiokande (S-K) upper limit on the neutrino flux from WIMP annihilation
in the Sun, and their compatibility with the "DAMA-compatible" regions of the
WIMP parameter space within which the annual modulation signal observed by the
DAMA/LIBRA experiment is compatible with the null results of other direct
detection experiments, are studied within the frame work of a self-consistent
model of the finite-size dark matter (DM) halo of the Galaxy, the parameters of
which are determined by a fit to the rotation curve data of the Galaxy. We find
that the S-K implied upper limits on the WIMP-proton elastic cross section as a
function of WIMP mass impose stringent restrictions on the branching fractions
of the various WIMP annihilation channels. For SI interaction, while the S-K
upper limits are consistent with the DAMA-compatible region of the WIMP
parameter space if the WIMPs annihilate dominantly to $\bbarb$\ and/or
$\cbarc$, portions of the DAMA-compatible region can be excluded if WIMP
annihilations to $\tautau$ and $\nu\anu$ occur at larger than ~ 10% and 0.1%
levels, respectively. For SD interaction, the restrictions on the possible
annihilation channels are much more stringent, essentially ruling out the
DAMA-compatible region of the WIMP parameter space if the relatively low-mass
($\sim$ 2 -- 20 GeV) WIMPs under consideration annihilate predominantly to any
mixture of $\bbarb$, \ $\cbarc$, \ $\tautau$, \ and $\nu\anu$ final states.

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    ABSTRACT: We consider a simple class of models in which the dark matter, X, is coupled to a new gauge boson, phi, with a relatively low mass (m_phi \sim 100 MeV-3 GeV). Neither the dark matter nor the new gauge boson have tree-level couplings to the Standard Model. The dark matter in this model annihilates to phi pairs, and for a coupling of g_X \sim 0.06 (m_X/10 GeV)^1/2 yields a thermal relic abundance consistent with the cosmological density of dark matter. The phi's produced in such annihilations decay through a small degree of kinetic mixing with the photon to combinations of Standard Model leptons and mesons. For dark matter with a mass of \sim10 GeV, the shape of the resulting gamma-ray spectrum provides a good fit to that observed from the Galactic Center, and can also provide the very hard electron spectrum required to account for the observed synchrotron emission from the Milky Way's radio filaments. For kinetic mixing near the level naively expected from loop-suppressed operators (epsilon \sim 10^{-4}), the dark matter is predicted to scatter elastically with protons with a cross section consistent with that required to accommodate the signals reported by DAMA/LIBRA, CoGeNT and CRESST-II.
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    Journal of Cosmology and Astroparticle Physics 12/2013; 2014(05). · 5.88 Impact Factor

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