The complementary of CTAO, direct detection and collider searches for dark matter in Effective Field Theories and Simplified models

Abstract

This paper explores the sensitivity of the Cherenkov Telescope Array Observatory to dark matter annihilation in the Galactic Center, within the frameworks of Effective Field Theory and Simplified Models. We present sensitivity forecasts, utilizing an up-to-date instrument configuration and incorporating the latest models for Galactic Diffuse Emission. A key aspect of our work is the inclusion of updated dark matter density profiles, J-factors, and velocity dispersion distributions derived from the FIRE-2 cosmological hydrodynamical simulations, which significantly impact the expected indirect detection signals. Furthermore, we update the constraints from direct detection experiments (Xenon1T and LZ) taking into account the astrophysical uncertainties informed by the FIRE-2 simulations, and also investigate limits coming from collider searches (ATLAS and CMS). Our analysis reveals improved constraints on the effective suppression scale ($M_*$) in the Effective Field Theory framework and on the mediator mass ($M_{med}$) in Simplified Models compared to previous studies, highlighting the complementarity of the Cherenkov Telescope Array Observatory with direct and collider searches in probing a wide range of dark matter scenarios. We discuss the implications of these results for various dark matter interaction types, including scalar, pseudoscalar, vector, and axial-vector mediators, and emphasize the importance of considering realistic astrophysical inputs in interpreting dark matter search results across different experimental fronts.

Figures (4)

• Figure 1: Left panel: DM density distribution in the GC region versus distance $r$ from the GC extracted from Fire-2 simulations of Milky Way-like galaxies. The black solid line shows the mean DM density, and the blue shaded region represents the range of possibilities from the set of simulation results of Ref. McKeown:2021sob. Right panel: Corresponding s-wave and p-wave J-factors as a function of the angular distance $\theta$ from the GC. The red and green solid lines stand for the mean J-factor for the s-wave and p-wave cases, respectively. The blue shaded region represents the possible range of values for the J-factors from the same set of simulations. For a reference on the data used in this Figure, see Ref. Hopkins:2017ycn.
• Figure 2: Energy-differential VHE gamma-ray flux expected in the EFT (top panels) and Simplified Model (bottom panels) approaches, respectively, for 1 TeV DM mass (left) and 100 TeV DM mass (right). The J-factor is taken as the mean value obtained from the 12 profiles discussed in Ref. McKeown:2021sob. The fluxes are integrated over the inner 5$^\circ$ of the GC excluding the masked regions. The expected fluxes are plotted for the four EFT operators representing scalar ($\mathcal{O}_S$), pseudoscalar ($\mathcal{O}_P$), vector ($\mathcal{O}_V$) and axial-vector ($\mathcal{O}_A$) interactions, with different values of $M_*$. For the simplified models, the expected fluxes are plotted for four effective operators featuring a scalar, pseudoscalar, vector or axial-vector mediators and two mediator masses, respectively. Also shown are the VHE gamma-ray backgrounds integrated in the same region as for the expected signals, including the CTAO residual background flux (dashed-dotted violet line) as well as our adopted GDE flux (orange dashed line).
• Figure 3: CTAO sensitivity for scalar (top left), pseudo-scalar (top right), vector (bottom left) and axial-vector (bottom right) EFT operators expressed in the (m$\chi$, M$_*$) plane. The sensitivity is expressed as the 95% C. L. mean expected lower limit. The thickness of the green line represents the impact of the lowest and highest J-factors. The red and orange-shaded areas show 90% C.L. lower limits derived from Xenon1T XENON:2018voc and LZ aalbers2024dark measurements, respectively. The 95% C. L. lower limit from a combination of the CMS CMS:2017zts and ATLAS ATLAS:2021kxv monojet/mono-X searches is shown by the violet line. The thickness of the red and orange lower limits are obtained considering the minimum and maximum velocity dispersion values from the distribution given in Ref. McKeown:2021sob. The blue-shaded regions show previous sensitivities extracted from Ref. Balazs:2017hxh assuming a DM distribution following a NFW profile. Finally, we display the contour $M_* = 2m_\chi$ as the black dashed line, for which only the region above the dashed line is kinematically available. The gray shaded region represents the region of the parameter space that is able to retrieve the DM relic abundance $\Omega_{\chi}h^{2} = 0.1186$.
• Figure 4: CTAO sensitivity (green shaded region) for pseudo-scalar (left) and vector (right) SM operators expressed in the (M$_{\rm med}$, m$_\chi$) plane. The sensitivity is expressed as the 95% C. L. mean expected lower limit. The dark shaded region shows the impact of the lowest and highest J-factors. The black dashed line corresponds to the contour of the kinematic constraint $M_{med} = 2m_\chi$, where only the region below the line is kinematically available. The red and orange shaded areas show 90% C.L. lower limits from Xenon1T XENON:2018voc and LZ aalbers2024dark, respectively. The violet and grey regions represent the exclusion limits from the ATLAS and CMS monojet searches aad2021searchtumasyan2021search for the pseudo-scalar case. As for the vector case, the purple region provides limits from ATLAS dijet constraints ATLAS:2024kpy and the gray region shows limits from the CMS monojet search tumasyan2021search. The thickness of red and orange lower limit curves represent the effect of considering the minimum and the maximum values of the dispersion velocity distribution given in Ref. McKeown:2021sob. The blue shaded squared regions show previous sensitivities extracted from Ref. Balazs:2017hxh assuming a DM distribution following a NFW profile. The gray shaded curves represents the region of the ($m_{\chi},\,M_{med}$) parameter space that is able to retrieve the DM relic abundance $\Omega_{\chi}h^{2} = 0.1186$.