Giant US collider plans to smash 50 billion gold atoms after 25 years of research

In RHIC’s 25th and final run, scientists will use the accelerator, detector, and data-capturing capabilities developed over the past two decades to explore the quark-gluon plasma with unprecedented precision.

Priorities and goals

Jin Huang, PhD, Brookhaven Lab physicist and co-spokesperson for RHIC’s newest detector, sPHENIX – capable of capturing snapshots of 15,000 particle collisions per second – highlights the extraordinary evolution of RHIC throughout the years.

“From its groundbreaking discoveries in creating and characterizing the quark-gluon plasma to its role in nurturing talent across the globe, RHIC has not only expanded the frontiers of nuclear science but also cultivated a deep, collaborative spirit among researchers,” Huang says.

“As we enter this final run, we carry forward the legacy of relentless inquiry, innovation, and mentorship that has defined RHIC’s journey.”

Run 25’s top priority is gold-gold collisions at 200 billion electron volts, and is set to run through early June. Operations will pause during the summer, while a mid-June review will evaluate progress and consider additional collision types depending on funding. Between collisions, the team will run 15-hour APEX – accelerator physics experiments – studies every two weeks to test ways to improve accelerator performance.

After years of upgrades completed in 2022, RHIC’s STAR detector will focus on maximizing data collection from 200 GeV gold-gold collisions. This year, researchers aim to collect an additional 10 billion of these events, in addition to the 8 billion gathered during Runs 23 and 24. In addition, the researchers also plan to use the detector’s real-time triggers to capture a large number of events rich in high-energy particles.

Meanwhile, the sPHENIX detector will operate at full capacity for the first time, aiming to collect data from 50 billion gold-gold collisions. The detector uses precision tracking and RHIC’s first barrel hadronic calorimeter to identify particles and measure their energy. This allows scientists to reconstruct energetic particle sprays called jets, which reveal how energy moves through the QGP.

What’s next

With APEX tests in Run 25, physicists are targeting key design challenges for the future Electron-Ion Collider (EIC), including how to keep ion beams stable and precisely aligned to maximize collision rates. They hope that the data, expertise, and detector technologies developed at RHIC will help pave the way for groundbreaking experiments.

“From RHIC to EIC, scientists are mapping the transition of nuclear matter from a hot, dense state, generated in gold-gold collisions, and then planning to use electrons – the smallest projectiles – to probe cold nuclear matter at the EIC,” Huang says in a press release.

Cold nuclear matter, the substance of atomic nuclei before collisions and the basis of all visible matter today, will link RHIC and EIC research in a complementary quest to understand the universe’s fundamental structure.

As construction of the new facility begins after this year’s RHIC run, scientists say they’re only at the beginning of a long road to discovery, with many exciting results expected in the years ahead.

“While our journey of data collection at RHIC will conclude after this run, the journey of discovery into the unknown will undoubtedly continue well into the next decade,” Brookhaven Lab physicist Lijuan Ruan and co-spokesperson for the STAR experiment, concludes.