Synopsis

Supernovae Could Confess Neutrinos’ Secrets

Physics 16, s120
A beyond-standard-model interaction between neutrinos could show up in future supernovae observations.
NASA-Goddard

Neutrinos are notoriously elusive. Interacting only via the weak force and gravity, they pass through regular baryonic matter almost unhindered. But like members of an exclusive social clique, neutrinos might be less standoffish among particles of their own type. Some beyond-standard-model theories predict a “secret” interaction that would cause neutrinos to scatter from one another when they gather at high enough densities. Po-Wen Chang at Ohio State University and his colleagues have now shown that, according to one neutrino-emission model, the effect of this neutrino self-interaction ( 𝜈SI) could show up in future observations of supernovae [1].

The team considers a core-collapse supernova that leaves behind a neutron star while producing a prodigious quantity of neutrinos. In the absence of 𝜈SI, these neutrinos should diffuse out of the nascent neutron star in around 10 seconds. The particles should then follow free trajectories to our detectors. But if 𝜈SI occurs, Chang and colleagues predict that neutrinos could form an expanding “neutrino fluid” in which the particles scatter from each other and propagate randomly. Only when the neutrino density drops below a threshold—determined by the interaction cross section—would the neutrinos begin their free trajectories.

As this 𝜈SI scenario involves emission from a much larger source region than the standard-model case, it could extend the time period over which neutrinos arrive from a supernova. To date, the only supernova neutrinos detected are the roughly 20 electron antineutrinos from SN 1987A, whose arrival times were consistent with the standard model. Recent advances in neutrino detection mean that researchers could detect thousands of neutrinos of all flavors from the next nearby supernova, increasing the likelihood of observing new physics.

–Marric Stephens

Marric Stephens is a Corresponding Editor for Physics Magazine based in Bristol, UK.

References

  1. P.-W. Chang et al., “Toward powerful probes of neutrino self-interactions in supernovae,” Phys. Rev. Lett. 131, 071002 (2023).

Subject Areas

Particles and FieldsAstrophysicsNuclear Physics

Related Articles

An Elusive Black Hole Comes into View
Astrophysics

An Elusive Black Hole Comes into View

Observations of seven fast-moving stars at the center of a dense star cluster in the Milky Way reveal the presence of an intermediate-mass black hole, perhaps the most puzzling class of these dark objects. Read More »

First Direct Detection of Electron Neutrinos at a Particle Collider
Particles and Fields

First Direct Detection of Electron Neutrinos at a Particle Collider

Electron neutrinos produced by proton–proton collisions at the LHC have been experimentally observed. Read More »

Dark Matter Could Bring Black Holes Together
Astrophysics

Dark Matter Could Bring Black Holes Together

Dark matter that interacts with itself could extract significant momentum from a binary supermassive black hole system, causing the black holes to merge. Read More »

More Articles