Macroscopic Dark Matter
Glenn Starkman
Co-Chair Dept of Physics
Director CERCA/ISO
Case Western Reserve University

Collaborators: J. Chiel D. Cyncynates, C. Covault, D. Dimastrogiovanni,
R. Harvey, D. Jacobs, S. Kumar, B, Lynn, J. Sidhu, R. Scherrer, A. Weltman

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

How could this be?
Interaction rates go as Γ ~ nX σX v ~ (σX/mX)ρX v
Gravitational observations fix ρX
What matters is (σX/mX) -- the “reduced cross-section”

DM can be low-mass-very-low-σ,or 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 and other smaller

SBBN, CMB

If DM is baryons it must be“sequestered” before BBN, and esp. before“recombination”

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?
Almost (?) Standard Model
Compact Composite Objects/
Baryonic Color Superconductors (+ axion) (Zhitnitsky, 2003)
Crypto-baryonic DM (Froggat & Nielsen, 2005)(Well) Beyond the Standard Modele.g. SUSY Q-balls, topological defect DM, …

Macros – what are they?
In 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

Dark Matter may be a Standard Model phenomenon!

So… what’s allowed for Macros?
A systematic probe of “macroscopic” dark matter candidates
that scatter geometrically with matter
Basic parameters: mass, cross section:
MX, σX=π RX2
Other parameters: charge (Q), composition (B>0 or B<0),surface composition, …

So… what’s allowed for Macros?
A systematic probe of “macroscopic” dark matter candidates
that scatter geometrically with matter
Basic parameters: mass, cross section:MX, σX=π RX2
Other parameters: charge (Q), composition (B>0 or B<0),surface composition, …

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

Old model-independent macro constraints

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

Model-independent constraints: people

J. Sidhu, R. Scherrer, GDS Physics Letters B 803, 135300 (2020);
arXiv:1907.06674

Model-independent limits: bolide searches

J. Sidhu, GDS, Phys.Rev.D 100 (2019) 12, 123008

Model-independent constraints: WD thermal runaways

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

Model-independent limits:
NSà SN; WD runaways (updated)

J. Sidhu, GDS Phys.Rev.D 101 , 083503 (2020); e-Print: 1912.04053

Prosepctive model-independent probes: granite slabs

J. Sidhu, R. Harvey, GDS, Phys.Rev.D 100 (2019) 10, 103015; e-Print: 1905.10025

Prosepctive model-independent probes: straight lightning

N. Starkman, J. Sidhu, H. Winch, GDS e-Print: 2006.16272

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 traverseatmosphere• Extremely large area
• Requires alterations to (hardware/software)
trigger to admit slow-moving macros

Model-dependent considerations

Model-dependent constraints:
Continued solar existence

Jacobs, GDS, Lynn (2014)

If the macro would “convert” ordinary matter, then solar stability requires

MX > 1024g or small enough σX

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, B. 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, cameras, the CMB spectrum ,seismological (terrestrial and lunar), atmospheric and marine observations(light, sound) , rocks, people, lightning
Such “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