Abstract
We discuss the extent to which models of Weakly Interacting Massive Particle (WIMP) Dark Matter (DM) at and above the electroweak scale can be probed conclusively in future high energy and astroparticle physics experiments. We consider simplified models with bino-like dark matter and slepton-like coannihilation partners, and find that perturbative models yield the observed relic abundance up to at least 10 TeV. We emphasise that coannihilation can either increase or decrease the dark matter relic abundance. We compute the sensitivity of direct detection experiments to DM-nucleus scattering, consider indirect detection bounds and estimate the sensitivity of future proton colliders to slepton pair production. We find that current and future experiments will be able to probe the Dirac DM models up to at least 10 TeV. However, current and future searches will not be sensitive to models of Majorana dark matter for masses above 2 or 4TeV, for one or ten coannihilation partners respectively, leaving around 70% of the parameter space unconstrained. This demonstrates the need for new experimental ideas to access models of coannihilating Majorana dark matter.
Highlights
JHEP10(2018)187 many experiments planned for the future, the clear question to answer is: ‘will they probe the whole neutralino parameter space?’ As such, it is important to identify viable scenarios in the sub-GeV and multi-TeV mass region, and to consider whether the suite of proposed experiments will successfully probe the entire region
These experiments are most sensitive to the dark matter mass range 10 GeV – 1 TeV, and the current leaders are LUX [25], PandaX-II [26] and XENON1T [27], which all use xenon as their target
Since thermal dark matter particles could annihilate into any standard model particles, there are a range of strategies looking for photons, neutrinos and a range of anti-matter produced in the galactic centre or in dwarf galaxies
Summary
In this work we focus on several related simplified models. As shown in table 1, we introduce dark matter as a Majorana or Dirac fermion, χ, and n copies of an uncoloured scalar coannihilation partner, φi, with unit hypercharge. We note that coannihilation is usually thought to increase the effective crosssection (as above), it can reduce the effective cross-section, increasing the dark matter relic abundance (as noted in, e.g., [5,6,7]). The extra cross-sections we add into eq (2.3) are small, and the dominant effect is to reduce σeff due to the increase of geff. In this situation, coannihilation increases the relic abundance. For Majorana χ, we see a balance between an increase in the effective cross-section due to the extra coannihilation processes and a decrease in σeff due to an increasing geff, which is especially pronounced in the n = 10 case. At 0.01 < ∆ < 0.2, we see that an increased geff, which reduces σeff, is the dominant effect
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
