Theoretical physics

Physicists have failed to find disintegrating protons, throwing into limbo the beloved theory that the forces of nature were unified at the beginning of time.

How do physicists reconstruct what really happened in a particle collision? Through calculations that are so challenging that, in some cases, they simply can’t be done. Yet.

An unexpected connection has emerged between the results of physics experiments and an important, seemingly unrelated set of numbers in pure mathematics.

So-called “analogue experiments” are becoming increasingly common in physics, but do they teach or mislead?

Can a fluid analogue of a black hole point physicists toward the theory of quantum gravity, or is it a red herring?

The theoretical particle physicist Helen Quinn has blazed a singular path from the early days of the Standard Model to the latest overhaul of science education in the United States.

String theory has so far failed to live up to its promise as a way to unite gravity and quantum mechanics. At the same time, it has blossomed into one of the most useful sets of tools in science.

The astrophysicist Tracy Slatyer is searching for faint wisps of dark matter annihilating in the early universe — and perhaps in hiding places closer to home.

The absence of supersymmetry particles at the Large Hadron Collider has settled a 16-year-old bet among physicists.