Snowmass2021 Cosmic Frontier White Paper: Ultraheavy particle dark matter

Abstract

We outline the unique opportunities and challenges in the search for "ultraheavy" dark matter candidates with masses between roughly 10 TeV and the Planck scale m pl ≈ 10 16 TeV. This mass range presents a wide and relatively unexplored dark matter parameter space, with a rich space of possible models and cosmic histories. We emphasize that both current detectors and new, targeted search techniques, via both direct and indirect detection, are poised to contribute to searches for ultraheavy particle dark matter in the coming decade. We highlight the need for new developments in this space, including new analyses of current and imminent direct and indirect experiments targeting ultraheavy dark matter and development of new, ultra-sensitive detector technologies like next-generation liquid noble detectors, neutrino experiments, and specialized quantum sensing techniques.

Neutron star observations of pseudoscalar-mediated dark matter

“…However, there are other ones explored in the literature: models of inelastic DM (thermal Higgsinos [19,22] and other electroweak multiplets [97]), and muon-philic DM in a gauged L µ −L τ model [37]. Yet more possibilities include DM in the keV-GeV mass range with small scattering cross sections, DM with large nuclear cross sections shielded by the rock overburden, composite DM with super-Planckian masses yielding too small a flux for direct searches [7,8,[98][99][100], models that lead to appreciable clustering of DM so that the Earth encounters DM clumps too infrequently [78], and so on. We leave these avenues of exploration to future authors.…”

“…Direct searches for DM in the form of a weakly interacting massive particle (WIMP) [1,2] have placed remarkable limits on DM over the mass range of m DM ∼ 1 GeV-100 TeV [3][4][5]. The absence of WIMP signals in direct detection experiments has also motivated searches for other DM candidates over a broader range of masses [6][7][8]. Notably, direct detection collaborations have made substantial progress in the "light" DM regime of sub-GeV masses, where the lower target recoil energies make scattering more difficult to detect, with current limits down to m DM ∼ 10 MeV in nuclear recoils and m DM ∼ 100 keV in electron recoils [9].…”

Supercomputers against strong coupling in gravity with curvature and torsion

“…Additional d.o.f may be tolerated unless ghostly or tachyonic 1 , but they must kept under close theoretical and phenomenological control (e.g. by large [19] -or small [20,21] -masses, screening [22] or other measures). Frequently we start with many fields (ten in the case of GR), so that reduction to two d.o.f is an achivement in the linearised Hamiltonian picture: strongly coupled modes may increase this number the nonlinear analysis [23].…”

Can radial motions in the stellar halo constrain the rate of change of mass in the Galaxy?

“…However many other avenues have been considered as early as in the 1980s, including the decay of dark matter particles, e.g., Dicus et al (1978); Cabibbo et al (1981) and Ellis et al (1984). Decaying dark matter scenarios gained further traction in the past two decades af-ter puzzling excesses in cosmic ray and X-ray observations emerged, see e.g., Chen et al (2009); Ibarra & Tran (2009); Yin et al (2009), or for more modern references von Doetinchem et al (2020); Carney et al (2022), as well as Boyarsky et al (2015); Jeltema & Profumo (2015); Riemer-Sørensen (2016) and references therein. As the injection of charged particles in dark matter halos and our cosmic neighbourhood could lead to excess in cosmic ray, neutrinos, Xray, gamma-ray and radio spectra, these could be used to set strong limits on the dark matter characteristics and, in particular, constrain its mass vs interaction strength and therefore lifetime.…”