Browse Physics

According to a new model, galaxies may contain disks made of a specific type of dark matter that can interact more strongly than most dark matter.

The first results from the space-borne Alpha Magnetic Spectrometer confirm an unexplained excess of high-energy positrons in Earth-bound cosmic rays.

The IceCube neutrino telescope reports its most extensive search for neutrinos produced by dark matter annihilations in the Sun.

Much can be learned about hypothetical particles called axions by studying the evolution of massive stars.

The H.E.S.S. Collaboration has put bounds on the flux of very-high-energy gamma rays that could be produced by annihilations of dark matter particles.

Cosmic gamma-ray bursts turn out to be polarized, which rules out the breaking of a fundamental symmetry down to the lowest limits ever observed.

Three major drawbacks to the ΛCDM dark matter model of the universe may be ameliorated if a proposed particle couples to dark matter and to neutrinos.

A new analysis shows that it is possible to look for dark-matter particles with mass far below 1 giga-electron-volt by using atomic ionization.

Interactions between primordial photons and axions may be why the accepted model of nucleosynthesis overestimates the abundance of the isotope lithium-7.

An underground neutrino detector has found the first evidence of a nuclear reaction that produces deuterium in the sun.

An unusual excess of radio emission from outside the Milky Way may come from dark matter.

A set of proposed relations among observable quantities may allow strong tests of whether a rapid expansion of the very early universe produced the seeds of the large-scale structure we see today.

New data from the PAMELA satellite on the abundance of antiprotons in cosmic rays still leave the door open for dark matter theories, as well as other explanations.

A comparison between the density in surrounding galaxies today and a few billion years ago provides a new upper bound on neutrino mass.

New calculation of quark matter properties tells us what an exotic quark-neutron star might look like.

A new calculation of stellar core-collapse explosions that includes all three neutrino flavors shows unusual spectral patterns that will be important in understanding signals from future galactic supernovae.

Theories of dark matter interacting with a light force carrier, proposed to explain the excess of high-energy positrons in the cosmic rays, turn out to have problems.

A model in which the dark matter relic density was inherited from the lepton asymmetry in the early universe can result in lepton-favoring dark matter annihilations today, which may explain recent anomalous cosmic-ray positron observations.

New measurements with the Fermi Large Area Telescope extend our knowledge of the extragalactic diffuse gamma-ray background and may help resolve the question of its origins.