Bernal, N., Martin-Albo, J., & Palomares-Ruiz, S. (2013). A novel way of constraining WIMPs annihilations in the Sun: MeV neutrinos. J. Cosmol. Astropart. Phys., 08(8), 011–19pp.
Abstract: Annihilation of dark matter particles accumulated in the Sun would produce a flux of high-energy neutrinos whose prospects of detection in neutrino telescopes and detectors have been extensively discussed in the literature. However, for annihilations into Standard Model particles, there would also be a flux of neutrinos in the MeV range from the decays at rest of muons and positively charged pions. These low-energy neutrinos have never been considered before and they open the possibility to also constrain dark matter annihilation in the Sun into e(+)e(-), mu(+)mu(-) or light quarks. Here we perform a detailed analysis using the recent Super-Kamiokande data in the few tens of MeV range to set limits on the WIMP-nucleon scattering cross section for different annihilation channels and computing the evaporation rate of WIMPs from the Sun for all values of the scattering cross section in a consistent way.
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Ruiz de Austri, R., & Perez de los Heros, C. (2013). Impact of nucleon matrix element uncertainties on the interpretation of direct and indirect dark matter search results. J. Cosmol. Astropart. Phys., 11(11), 049–19pp.
Abstract: We study in detail the impact of the current uncertainty in nucleon matrix elements on the sensitivity of direct and indirect experimental techniques for dark matter detection. We perform two scans in the framework of the cMSSM: one using recent values of the pion-sigma term obtained from Lattice QCD, and the other using values derived from experimental measurements. The two choices correspond to extreme values quoted in the literature and reflect the current tension between different ways of obtaining information about the structure of the nucleon. All other inputs in the scans, astrophysical and from particle physics, are kept unchanged. We use two experiments, XENON100 and IceCube, as benchmark cases to illustrate our case. We find that the interpretation of dark matter search results from direct detection experiments is more sensitive to the choice of the central values of the hadronic inputs than the results of indirect search experiments. The allowed regions of cMSSM parameter space after including XENON100 constrains strongly differ depending on the assumptions on the hadronic matrix elements used. On the other hand, the constraining potential of IceCube is almost independent of the choice of these values.
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Bozorgnia, N., Herrero-Garcia, J., Schwetz, T., & Zupan, J. (2013). Halo-independent methods for inelastic dark matter scattering. J. Cosmol. Astropart. Phys., 07(7), 049–15pp.
Abstract: We present halo-independent methods to analyze the results of dark matter direct detection experiments assuming inelastic scattering. We focus on the annual modulation signal reported by DAMA/LIBRA and present three different halo-independent tests. First, we compare it to the upper limit on the unmodulated rate from XENON100 using (a) the trivial requirement that the amplitude of the annual modulation has to be smaller than the bound on the unmodulated rate, and (b) a bound on the annual modulation amplitude based on an expansion in the Earth's velocity. The third test uses the special predictions of the signal shape for inelastic scattering and allows for an internal consistency check of the data without referring to any astrophysics. We conclude that a strong conflict between DAMA/LIBRA and XENON100 in the framework of spin-independent inelastic scattering can be established independently of the local properties of the dark matter halo.
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Lopez-Honorez, L., Mena, O., Palomares-Ruiz, S., & Vincent, A. C. (2013). Constraints on dark matter annihilation from CMB observations before Planck. J. Cosmol. Astropart. Phys., 07(7), 046–26pp.
Abstract: We compute the bounds on the dark matter (DM) annihilation cross section using the most recent Cosmic Microwave Background measurements from WMAP9, SPT'11 and ACT'10. We consider DM with mass in the MeV-TeV range annihilating 100% into either an e(+)e(-) or a mu(+)mu(-) pair. We consider a realistic energy deposition model, which includes the dependence on the redshift, DM mass and annihilation channel. We exclude the canonical thermal relic abundance cross section (<sigma nu > = 3 x 10(-26) cm(3)s(-1)) for DM masses below 30 GeV and 15 GeV for the e(+)e(-) and mu(+)mu(-) channels, respectively. A priori, DM annihilating in halos could also modify the reionization history of the Universe at late times. We implement a realistic halo model taken from results of state-of-the-art N-body simulations and consider a mixed reionization mechanism, consisting on reionization from DM as well as from first stars. We find that the constraints on DM annihilation remain unchanged, even when large uncertainties on the halo model parameters are considered.
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Bernal, N., Colucci, S., Josse-Michaux, F. X., Racker, J., & Ubaldi, L. (2013). On baryogenesis from dark matter annihilation. J. Cosmol. Astropart. Phys., 10(10), 035–30pp.
Abstract: We study in detail the conditions to generate the baryon asymmetry of the universe from the annihilation of dark matter. This scenario requires a low energy mechanism for thermal baryogenesis, hence we first discuss some of these mechanisms together with the specific constraints due to the connection with the dark matter sector. Then we show that, contrary to what stated in previous studies, it is possible to generate the cosmological asymmetry without adding a light sterile dark sector, both in models with violation and with conservation of B – L. In addition, one of the models we propose yields some connection to neutrino masses.
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