10-17 July 2019
Ghent
Europe/Brussels timezone

Scrutinizing the evidence for dark matter in cosmic-ray antiprotons

12 Jul 2019, 12:50
20m
Campus Ledeganck - Aud. 2 (Ghent)

Campus Ledeganck - Aud. 2

Ghent

Parallel talk Cosmology Cosmology

Speaker

Dr Jan Heisig (Université catholique de Louvain (UCL))

Description

Global fits of primary and secondary cosmic-ray (CR) fluxes measured by AMS-02
have great potential to study CR propagation models and search for exotic
sources of antimatter such as annihilating dark matter (DM). Previous studies
of AMS-02 antiprotons revealed a possible hint for a DM signal which, however,
could be affected by systematic uncertainties. To test the robustness of such a
DM signal, in this work we systematically study two important sources of
uncertainties: the antiproton production cross sections needed to calculate the
source spectra of secondary antiprotons and the potential correlations in the
experimental data, so far not provided by the AMS-02 collaboration. To
investigate the impact of cross-section uncertainties we perform global fits of
CR spectra including a covariance matrix determined from nuclear cross-section
measurements. As an alternative approach, we perform a joint fit to both the CR
and cross-section data. The two methods agree and show that cross-section
uncertainties have a small effect on the CR fits and on the significance of a
potential DM signal, which we find to be at the level of 3 sigma. Correlations
in the data can have a much larger impact. To illustrate this effect, we
determine possible benchmark models for the correlations in a data-driven
method. The inclusion of correlations strongly improves the constraints on the
propagation model and, furthermore, enhances the significance of the DM signal
up to above 5 sigma. Our analysis demonstrates the importance of providing the
covariance of the experimental data, which is needed to fully exploit their
potential.

Primary author

Dr Jan Heisig (Université catholique de Louvain (UCL))

Presentation Materials