Macroscopic Dark Matter
Glenn Starkman
Dept of Physics/CERCA/ISO
Case Western Reserve University
Collaborators: Jagjit Sidhu,
Bob Scherrer, David Jacobs, Bryan Lynn, K. McGee,
S. Kumar, E. Dimastrogiovannit
A. Weltman: D. Cyncynates, J. ChielAn Uncooperative Universe:
large scale anomalies in the CMB

Craig Copi, Dragan Huterer & Dominik Schwarz
Francesc Ferrer, Amanda Yoho
S. Aiola, A. Kosowsky
L. Knox, Marcio O’Dwyer

What do we really know about DM?
Dark:
does not automatically mean σ is small!

How could this be?
Interaction rates Γ ~ n X σ X v ~ (σ X /m X ) ρ X v
Gravitational observations fix ρ X
Galactic dynamics fix v
What’s left is (σ X /m X ) -- the “reduced cross-section”

DM can be low-mass-very-low-σ -- particle DMor high-mass-not-so-low-σ !
MACROscopic Dark Matter

What do we know about DM σ?
Strongly-interacting dark matter:
Starkman et al. (1990), …, Macket al. (2007)
More or less constrained up to ~1017 GeVWhat about macroscopic stuff – m > ~1g ?

Macros – what are they?
Ordinary Standard Model matter:
Stellar remnants – WD, NS, BH
Planets, asteroids, comets, …

SBBN, CMB

If DM is baryons they must be“sequestered” before BBN

Macros – what are they?
Primordial Black HolesIn the Standard Model
Strange Quark Nuggets, Witten (1984)
Strange Baryon Matter (Lynn et al., 1990)
Strange Chiral Liquid Drops (Lynn, 2010)
Other names: nuclearites, strangelets, ,CUDOs

Macros – what are they?
Barely BSM
Compact Composite Objects/
Baryonic Color Superconductors (+ axion) (Zhitnitsky, 2003)
Crypto-baryonic DM (Froggat & Nielsen, 2005)

Clearly BSM
e.g. SUSY Q-balls, topological defect DM, …

So… what’s allowed for Macros?
A systematic probe of “macroscopic” dark mattercandidates that scatter geometrically with matter
Basic parameters: mass, cross section:

M X,

2
σ X=π R X

Model-independent constraints
Gravitational effects (lensing)
Elastic and inelastic coupling ofMacros to baryons
Macros to other Macros
Macros to photons

Old model-independent macro constraints

Cyncynates et al. (2016); updated by J. Sidhu

Model-independent constraints: WD thermal runaways

P. W. Graham, S. Rajendran, and J. Varela, Phys. Rev. D 92, 063007 (2015)

Model-independent limits:yranimilepr

J. Sidhu, GDS in preparation

Model-independent constraints: people

J. Sidhu, R. Scherrer, GDS arXiv:1907.06674

Model-independent limits: meteor searches

J. Sidhu, GDS, arXiv:1908.00557

Future Probes

Model-independent probes: granite slabs

J. Sidhu, R. Harvey, GDS, arXiv:1905.10025

Model-independent probes: UHECR detectors

J. Sidhu, R. Abraham, C. Covault, GDS (2019) JCAP 1902, 2037

UHECR detectors: Auger, JEM-USO
J. Sidhu, R. Abraham, C. Covault, GDS (2019) JCAP 1902, 2037

• Detect N fluoresence as macros traverse
atmosphere• Extremely large area
• Requires alterations to (hardware/software)
trigger to admit slow-moving macros

CMB Spectral Distortions
S. Kumar et al. Phys. Rev D99 (2019) 023521• Macros cool by neutrino and photo emission• Will stay warmer than the surrounding plasma• Results in y, mu and intermediate distortions.
• Model dependent: use neutron star as proxy forstraw man

RESULTS: T vs. z

Saurabh Kumar, E. Dimastrogiovanni, GDS, C. Copi, L. Lynn.

RESULTS: ! & y distortion

Saurabh Kumar, E. Dimastrogiovanni, GDS, C. Copi, B. Lynn.

Conclusions
Dark matter doesn’t have to interact weakly if it’s very massive.

It might even arise within the Standard Model.

Regardless of its nature, there are unconstrained regions of size vs. mass.
There are many potential probes: UHECR detectors, the CMB spectrum ,seismological (terrestrial and lunar), atmospheric and marine observations(light, sound) , rocks, peopleSuch “strongly”-interacting dark matter candidates may (not) be relevant tooutstanding issues in CDM cosmology (cusp vs. core, missing satellites,…)
We need to extend existing searches and explore the full parameter space