Synopsis: The Heavy Limit of Dark Matter

A theoretical investigation of super-heavy dark matter particles finds that their existence might be discerned in the cosmic microwave background.

Dark matter is often assumed to consist of particles that weigh as much as a proton but interact like a neutrino. However, dark matter particles could be much heavier, as well as much less interacting. New work from a team of theorists explores the upper limit of mass with a dark matter candidate that they call Planckian interacting dark matter (PIDM). The researchers show that the PIDM model implies a large number of primordial gravitational waves, which could produce a detectable signal in forthcoming cosmic microwave background (CMB) observations.

Dark matter candidates are not hard to come by. Many theories predict weakly interacting particles with masses near the electroweak scale (roughly 100 times the proton mass). These so-called WIMPs would presumably be created in the hot, dense, early Universe with an abundance that is consistent with the dark matter mass density observed in the current Universe.

The trouble is that collider experiments have yet to see any hints of WIMPs, which might mean that researchers will have to look beyond the electroweak scale. Mathias Garny of CERN and his colleagues from CP3-Origins in Denmark propose a particle with a mass near another natural scale, the Planck mass (1019 times the proton mass, or about a microgram). The team assumed these PIDM particles interact with ordinary matter only through gravitation and that large numbers of them formed in the very early Universe during the cosmological epoch called “reheating.” For this model to work, however, the temperature of reheating would have to be higher than usually assumed. A hotter reheating would result in more gravitational waves, which could be confirmed (or ruled out) by next-generation CMB experiments.

This research is published in Physical Review Letters.

–Michael Schirber


Features

More Features »

Announcements

More Announcements »

Subject Areas

Particles and Fields

Previous Synopsis

Chemical Physics

Shape Shifting Water Droplets

Read More »

Next Synopsis

Materials Science

Waves That Shock Resistance

Read More »

Related Articles

Viewpoint: Black Hole Evolution Traced Out with Loop Quantum Gravity
Particles and Fields

Viewpoint: Black Hole Evolution Traced Out with Loop Quantum Gravity

Loop quantum gravity—a theory that extends general relativity by quantizing spacetime—predicts that black holes evolve into white holes. Read More »

Viewpoint: The Plot Thickens for a Fourth Neutrino
Particles and Fields

Viewpoint: The Plot Thickens for a Fourth Neutrino

Confirming previous controversial results, the MiniBooNE experiment detects a signal that is incompatible with neutrino oscillations involving just the three known flavors of neutrinos. Read More »

Viewpoint: Dissecting the Mass of the Proton
Nuclear Physics

Viewpoint: Dissecting the Mass of the Proton

A calculation determines four distinct contributions to the proton mass, more than 90% of which arises entirely from the dynamics of quarks and gluons. Read More »

More Articles