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Register a new userCosmic-ray antiproton excess from annihilating tensor dark matter
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Added by
Haydee Hern\\'andez-Arellano
Publication date
2021
fields
Physics
and research's language is
English
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In this work we show that the excess of antiprotons in the range $E_{K}=10-20 ~GeV$ reported by several groups in the analysis of the AMS-02 Collaboration data, can be explained by the production of antiprotons in the annihilation of dark matter with a $(1,0)oplus (0,1)$ space-time structure (tensor dark matter). First, we calculate the proton and antiproton flux from conventional mechanisms and fit our results to the AMS-02 data, confirming the antiproton excess. Then we calculate the antiproton production in the annihilation of tensor dark matter. For the window $Min [62.470,62.505] ~ GeV$ to which the measured relic density, XENO1T results and the gamma ray excess from the galactic center constrain the values of the tensor dark matter mass, we find sizable contributions of antiprotons in the excess region from the annihilation into $bar{b}b$ and smaller contributions from the $bar{c}c$ channel. We fit our results to the AMS-02 data, finding an improvement of the fit for these values of $M$.
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The CoGeNT experiment, dedicated to direct detection of dark matter, has recently released excess events that could be interpreted as elastic collisions of $sim$10 GeV dark matter particles, which might simultaneously explain the still mysterious DAMA/LIBRA modulation signals, while in conflict with results from other experiments such as CDMS, XENON-100 and SIMPLE. It was shown that 5-15 GeV singlino-like dark matter candidates arising in singlet extensions of minimal supersymmetric scenarios can fit these data; annihilation then mostly proceeds into light singlet-dominated Higgs (pseudo)scalar fields. We develop an effective Lagrangian approach to confront these models with the existing data on cosmic-ray antiprotons, including the latest PAMELA data. Focusing on a parameter space consistent with the CoGeNT region, we show that the predicted antiproton flux is generically in tension with the data whenever the produced (pseudo)scalars can decay into quarks energetic enough to produce antiprotons, provided the annihilation S-wave is significant at freeze out in the early universe. In this regime, a bound on the singlino annihilation cross section is obtained, $sigvlesssim 10^{-26},{rm cm^3/s}$, assuming a dynamically constrained halo density profile with a local value of $rho_odot = 0.4,{rm GeV/cm^3}$. Finally, we provide indications on how PAMELA or AMS-02 could further constrain or detect those configurations producing antiprotons which are not yet excluded.
We consider a simple extension of the type-II two-Higgs-doublet model by introducing a real scalar as a candidate for dark matter in the present Universe. The main annihilation mode of the dark matter particle with a mass of around $31-40$ GeV is into a $bbar{b}$ pair, and this annihilation mode suitably explains the observed excess of the gamma-ray flux from the Galactic Center. We identify the parameter region of the model that can fit the gamma-ray excess and satisfy phenomenological constraints, such as the observed dark matter relic density and the null results of direct dark matter search experiments. Most of the parameter region is found to be within the search reach of future direct dark matter detection experiments.
Light non-relativistic components of the galactic dark matter halo elude direct detection constraints because they lack the kinetic energy to create an observable recoil. However, cosmic-rays can upscatter dark matter to significant energies, giving direct detection experiments access to previously unreachable regions of parameter-space at very low dark matter mass. In this work we extend the cosmic-ray dark matter formalism to models of inelastic dark matter and show that previously inaccessible regions of the mass-splitting parameter space can be probed. Conventional direct detection of non-relativistic halo dark matter is limited to mass splittings of $deltasim10~mathrm{keV}$ and is highly mass dependent. We find that including the effect of cosmic-ray upscattering can extend the reach to mass splittings of $deltasim100~mathrm{MeV}$ and maintain that reach at much lower dark matter mass.
We propose a model of dark matter identified with a pseudo-Nambu-Goldstone boson in the dynamical supersymmetry breaking sector in a gauge mediation scenario. The dark matter particles annihilate via a below-threshold narrow resonance into a pair of R-axions each of which subsequently decays into a pair of light leptons. The Breit-Wigner enhancement explains the excess electron and positron fluxes reported in the recent cosmic ray experiments PAMELA, ATIC and PPB-BETS without postulating an overdensity in halo, and the limit on anti-proton flux from PAMELA is naturally evaded.
Recently reported tentative evidence for a gamma-ray line in the Fermi-LAT data is of great potential interest for identifying the nature of dark matter. We compare the implications for decaying and annihilating dark matter taking the constraints from continuum gamma-rays, antiproton flux and morphology of the excess into account. We find that higgsino and wino dark matter are excluded, also for nonthermal production. Generically, the continuum gamma-ray flux severely constrains annihilating dark matter. Consistency of decaying dark matter with the spatial distribution of the Fermi-LAT excess would require an enhancement of the dark matter density near the Galactic center.
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