The start of this year’s physics run at the Relativistic Heavy Ion Collider (RHIC) also marks the start of a new era. For the first time since RHIC began operating at the U.S. Department of Energy’s Brookhaven National Laboratory in 2000, a brand new detector will track what happens when the nuclei of gold atoms smash into one another at nearly the speed of light. That new detector, sPHENIX, has been a decade in the making. It has a host of components for making precision measurements never possible before at RHIC.
RHIC’s STAR detector, which has been running and evolving since 2000, will also see some firsts in Run 23. Its most recently upgraded components allow the detector to “see” more particles streaming out of collisions closer to the collision point and at wider angles than ever before. This suite of components, which operated successfully in lower-energy collisions, will now collect data from full-energy collisions for the first time. In addition, STAR physicists look forward to flexing the detector’s capacity for capturing up to 5,000 collision events per second, more than double its rate in any previous year.
“There’s a very rich physics program to be run and great interest worldwide—and in the media—in this physics program,” said Jamie Dunlop, Brookhaven Lab Physics Department Associate Chair for Nuclear Physics, pointing out a recent article in Scientific American about this year’s plans for RHIC.
One reason for that interest? RHIC’s research delves into the matter that makes up everything visible in the universe today—stars, planets, and even you and me. RHIC scientists use particle collisions to study that matter by effectively turning back the hands of time.
Colliding atomic nuclei at very high energies melts the boundaries of individual protons and neutrons, setting free those particles’ innermost building blocks: quarks and gluons. Such a system of “free” quarks and gluons—known as a quark-gluon plasma (QGP)—existed in nature some 14 billion years ago, a millionth of a second after the birth of the universe, before protons and neutrons formed. Studying this substance using detectors like STAR and sPHENIX offers clues to why matter behaves the way it does.