Baruch’s Nuclear Physicists Prepare to Look Into the Heart of the Proton and Back to The Beginning of Universe

March 3, 2023

Professors Stefan Bathe, Adrian Dumitru, and Jamal Jalilian-Marian, have spent their careers working on discovering what forces and constituents make up the proton, the positively charged particle at the core of every atom. They are colleagues in Baruch’s Department of Natural Sciences.

Professor Bathe’s latest experiment, sPHENIX, a new detector part of the enormous Relativistic Heavy Ion Collider particle accelerator, will start collecting data in two months’ time. The accelerator aims to recreate the conditions that existed just moments after the Big Bang, before atoms as we know them had the chance to form. This primordial soup, known as “quark-gluon plasma,” out of which sprang the building blocks of our universe, may hold the key to uncovering what exactly comprises the proton, and hence matter itself.

sPHENIX, housed in Long Island’s Brookhaven National Laboratory, has been in the making for the past twelve years. For the past five, Baruch’s experimental nuclear physics group has been leading the effort of assembling, testing, calibrating, and installing the hadronic calorimeter, a principal detector system of sPHENIX. Professor Bathe is serving as the 2023 Run Coordinator of the experiment, responsible for the inaugural 24-week data-taking period. During this period, atomic nuclei will be hurled at each other at 99.995% of the speed of light, resulting in collisions that produce explosions of quark-gluon plasma, a substance that hasn’t existed since the dawn of time. sPHENIX will help the team detect the components within.

“We are thrilled that our new detector will be coming to life soon,” said Professor Bathe “A new, high-energy physics detector of this scale coming online is an event that happens only a few times in a research career.”

Professors Dumitru and Jalilian-Marian have both published seminal papers that helped lead to this historic experiment, specifically on those proton constituents that carry a low momentum fraction. This quest for the origin of one the proton’s key building blocks, the proton spin, was one the main drivers of the original PHENIX experiment which Professor Bathe worked on for two decades, co-authoring numerous papers.

Read more in two articles in Scientific America here and here.

Quanta Magazine published an aptly titled article and podcast “Inside the Proton, the ‘Most Complicated Thing You Could Possibly Imagine,'” here.

Nuclear physicists at MIT and Jefferson Lab, together with MIT filmmakers, have produced an animation of the proton intended for use in high school classrooms. Check it out here.

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