The experiments at the Large Hadron Collider (LHC) detect rare events on a daily basis, but some are exceptionally rare, such as this latest result from the CMS collaboration. For the first time, the collaboration has observed the production of a single top quark along with a W and a Z boson, an extremely rare process that happens only once every trillion proton collisions. Finding this event in the LHC data is like searching for a needle in a haystack the size of an Olympic stadium.

The creation of a top quark, a W boson and a Z boson, known as tWZ production, opens up a new window for understanding the fundamental forces of nature. By closely studying tWZ production, physicists can investigate how the top quark interacts with the electroweak force, which is carried by the W and Z bosons.

In addition, the top quark is the heaviest known fundamental particle, meaning that it has the strongest interaction with the Higgs field, so, studying the tWZ process could give us a deeper understanding of the Higgs mechanism. It could also point us to signs of new phenomena and physics beyond the Standard Model.

On July 4, 2012, researchers at the Large Hadron Collider (LHC) in Switzerland announced with great fanfare that they had successfully detected the Higgs boson, the manifestation of the mechanism that gives some elementary particles their mass. The finding was a triumph of both the experimental skill required to definitively detect the particle, and the theoretical acumen of those who predicted its existence, recognized by the 2013 Nobel Prize in Physics.

Brown University researchers played key roles in both sides of the accomplishment. Experimentalists including David Cutts, Ulrich Heintz, Greg Landsberg and the late Meenakshi Narain made key contributions to the Compact Muon Solenoid (CMS) experiment at the LHC credited with making the discovery. Years earlier, the late Gerald Guralnik was part of a group that made a theoretical prediction of the particle, which many scientists believe to be the most complete description of the Higgs mechanism.

The Higgs was the final missing piece in the standard model of particle physics —the theory that describes the basic building blocks of the universe. But its discovery was by no means a final destination for particle physics. Fundamental questions about the Higgs itself remain unanswered.

Hydrogen is already an important source of energy. The $250 billion industry supports fertilizer production, steel manufacturing, oil refining, and dozens of other vital activities. While nearly all hydrogen produced today is created using carbon-intensive methods, researchers are racing to develop cheaper ways of producing hydrogen with a lower carbon footprint.

One of the most promising approaches is water electrolysis, a process that uses electricity to power a reactor—called an electrolyzer—to split water (H₂O) molecules into hydrogen (H₂) and oxygen (O₂).

Electrolyzers rely on a thin membrane that blocks O₂ and H₂ molecules while allowing positively charged hydrogen atoms —called protons—to pass through.

In a Physical Review Letters study, the HOLMES collaboration has achieved the most stringent upper bound on the effective electron neutrino mass ever obtained using a calorimetric approach, setting a limit of less than 27 eV/c² at 90% credibility.

This result validates a decades-old experimental vision and demonstrates the scalability needed for next-generation neutrino mass experiments.

While oscillation experiments have measured the differences between neutrino mass states, the actual individual mass values—the absolute neutrino mass scale—remain unknown. Pinning down these values would help complete our understanding of the Standard Model of particle physics.

Researchers have proposed that exotic particles emitted by the Large Hadron Collider’s relativistic beams might reveal themselves in collisions of their own.