Symmetry magazine

11/12/2025

In 2023, the ALICE experiment was ready for their best year yet, until a mysterious signal threatened everything. As the LHC wraps up its 2025 lead-ion run, physicists recall how they worked together to solve the puzzle.

09/12/2025

The barrel of the new CMS timing detector will consist of thousands of crystal sensors embellished around a cylindrical support structure that is the size of a small research submarine. When a passing particle hits a crystal, it generates a flash of light. This flash is immediately picked up by an attached photomultiplier, which converts the light into an electronic signal, which is then sent to a circuit board and time stamped.

According to University of Virginia postdoc Bryan Cardwell, the concept is inherently simple. The complexity arises from the detector’s size and location inside CMS.

08/12/2025

University of Virginia postdoc Bryan Cardwell explains the simple math behind the new CMS timing detector that will let them calculate a key feature of particles: their mass. The two things they need are a measurement of how much the charged particles bend while they travel through CMS’s magnetic field (which gives momentum) and when the particles hit the timing detector (which gives velocity.) From this, they can use the equation momentum = mass x velocity to figure out the mass of the particles.

04/12/2025

The new CMS timing detector will help scientists hunt for dark matter by allowing scientists to isolate and identify slow moving particles, University of Virginia postdoc Bryan Cardwell explains.

01/12/2025

Photons, for centuries both a puzzle and a tool, continue to help scientists illuminate nature at the smallest and largest scales.

01/12/2025

University of Virginia postdoc Bryan Cardwell explains how “time” might be the missing ingredient in the international search for dark matter. The new CMS timing detector will give physicists a new way to look at particle collisions and search for slow moving dark matter. According to Cardwell, it’s entirely possible that the LHC has been producing dark matter this whole time, but that physicists haven’t found it because it’s been impossible to disentangle dark matter from everything else.

26/11/2025

Humans are great particle detectors. But to chase the biggest mysteries in the universe, physicists need bigger and better particle detectors that go beyond the capabilities of human senses. That’s why scientists built the CMS experiment at CERN, which is currently undergoing a massive upgrade to give it a new superpower: ultra precise timing. Stay tuned for Part 3 in which University of Virginia postdoc Bryan Cardwell will explain how it works.

19/11/2025

Something is out there. As far as scientists know, just 15% of the matter in the universe is the ordinary kind we can see. The other 85%, called dark matter, remains beyond detection, invisibly affecting the movements of galaxies and subtly warping our view of the stars.

24/09/2025

It’s April 2025, and the NSF–DOE Vera C. Rubin Observatory control room at the Department of Energy’s SLAC National Accelerator Laboratory is buzzing with activity. On the Menlo Park campus in California, on the first floor of the home of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), you will find the lab’s Rubin Operations Center. There a small group of scientists and engineers have gathered in front of a wall of oversized screens for a milestone moment: the witnessing of “First Photon,” the very first raw image captured by the Legacy Survey of Space and Time (LSST) Camera, built at SLAC and now installed on Rubin Observatory’s telescope in Chile.

All eyes are fixed on a live stream of data flowing from Cerro Pachón, thousands of kilometers away in northern Chile. Then, suddenly, it appears: an image of the night sky, freshly captured by the LSST Camera. The image fills the screen, and smiles spread across the room. This is the very first LSSTCam on-sky image ever received in this room. The first of many to come.

But the Rubin control room at SLAC is more than a place of emotion and discovery.

With survey operations set to begin this fall, the Rubin control room at SLAC will serve as a key hub for training and remote observing support for the NSF–DOE Vera C. Rubin Observatory.

05/08/2025

The Standard Model of particle physics divides particles into three generations. After more than a decade of studying the Higgs boson, scientists have confirmed that the Higgs field interacts with the heaviest, third-generation particles. But does the Higgs also have a relationship with the two lighter generations of particles?

Physicists Huilin Qu and Loukas Gouskos wanted to see if machine learning could get them closer to finding out.

A team of young scientists paused their new physics searches to develop an innovative machine-learning tool, which is now helping them narrow in on a rare and messy decay of the Higgs boson.