Signs of Gluon Saturation Emerge from Particle Collisions

By colliding protons with heavier ions and tracking particles from these collisions, scientists can study the quarks and gluons that make up protons and neutrons. Recent results revealed a suppression of certain back-to-back pairs of particles that emerge from interactions of single quarks from the proton with single gluons in the heavier ion. The results suggest that gluons in heavy nuclei recombine, a step toward proving that gluons reach a postulated steady state called saturation, where gluon splitting and recombination balance.

Simons Foundation Announces New Collaboration on Confinement and QCD Strings

The Simons Foundation has announced a new research collaboration to explore the “glue” that holds the visible matter of the universe together. This team will delve into the details of quantum chromodynamics (QCD) — the theory that describes the interactions among the most fundamental building blocks of visible matter.

Nuclear Physicists Hunt for Clues of Color Transparency in Protons

Protons inside the nucleus cling to neighboring protons and neutrons. However, it may be possible to knock out protons so that they interact less with nearby particles as they exit the nucleus, a phenomenon called color transparency. Physicists have observed color transparency in two-quark particles. But physicists hunting for signs of color transparency in protons in a more complicated three-quark system recently came up empty handed.

Calculating Hadrons Using Supercomputers

Hadrons are elusive superstars of the subatomic world, making up almost all visible matter, and British theoretical physicist Antoni Woss has worked diligently with colleagues at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility to get to know them better. Now, Woss’ doctoral thesis on spinning hadrons has earned him the 2019 Jefferson Science Associates Thesis Prize.

Precise Measurement of Pions Confirms Understanding of Fundamental Symmetry

Nuclear physicists have announced the most precise measurement yet of the ultra-short lifetime of the neutral pion. The result is an important validation of our understanding of the theory of quantum chromodynamics, which describes the makeup of ordinary matter. The research, carried out at the Department of Energy’s Thomas Jefferson National Accelerator Facility, was recently published in the journal Science.

Analyzing Matter’s Building Blocks

Nobuo Sato is working to put the know in femto. He’s just been awarded a five-year, multimillion dollar research grant by the Department of Energy to develop a “FemtoAnalyzer” that will help nuclear physicists image the three-dimensional internal structure of protons and neutrons. Now, Sato is among 76 scientists nationwide who have been awarded a grant through the DOE Office of Science’s Early Career Research Program to pursue their research.