Nuclear Physics

One of the enduring mysteries of the universe is the nature of matter—what are its basic constituents and how do they interact to form the elements and the properties we observe? The mission of the Nuclear Physics (NP) program is to solve this mystery by discovering, exploring, and understanding all forms of nuclear matter. Nuclear physicists seek to understand not just the familiar forms of matter we see around us, but also exotic forms such as those that existed in the first moments after the Big Bang and that exist today inside neutron stars. The aim is to understand why matter takes on the specific forms now observed in nature and how that knowledge can benefit society in the areas of commerce, medicine, and national security.

The quest to understand the properties of different forms of nuclear matter requires long-term support for both theoretical and experimental research efforts. Theoretical approaches are based on calculations of the interactions of quarks and gluons, which form protons and neutrons, using today’s most advanced computers. Other theoretical research models the forces between protons and neutrons and seeks to understand and predict the structure of nuclear matter. Experiments in nuclear physics use large accelerators that collide particles at nearly the speed of light, producing short-lived forms of matter for investigation. Nuclear physicists also use low-energy, precision nuclear experiments, many enabled by new quantum sensors, to search for a deeper understanding of fundamental symmetries and nuclear interactions. Comparing experimental observations and theoretical predictions tests the limits of our understanding of nuclear matter and suggests new directions for experimental and theoretical research.

Highly trained scientists who conceive, plan, execute, and interpret transformative experiments are at the heart of the NP program. NP supports these university and national laboratory scientists. We also support U.S. participation in select international collaborations and provide over 90 percent of the nuclear science research funding in the United States. The world-class scientific user facilities and associated instrumentation necessary to advance the U.S. nuclear science program are large and complex. NP supports three scientific user facilities: the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL); the Continuous Electron Beam Accelerator Facility (CEBAF) at Thomas Jefferson National Accelerator Facility (TJNAF); and the Argonne Tandem Linac Accelerator System (ATLAS) at Argonne National Laboratory (ANL). NP is also constructing the Facility for Rare Isotope Beams to provide unprecedented opportunities to study the synthesis of the heavy elements in the cosmos. Each of these facilities has unique capabilities that advance NP’s scientific mission.  

The Nuclear Physics Program also manages the DOE Isotope Program, which supports the production, distribution, and development of production techniques for radioactive and stable isotopes in short supply and critical to the nation. Isotopes are commodities of strategic importance for the nation. They are essential for energy exploration and innovation, medical applications, national security, and basic research. The goal of the program is to make key isotopes more readily available to meet U.S. needs. The program also supports R&D efforts to develop new and more cost-effective and efficient production and processing techniques. The R&D activities provide collateral benefits for training, contributing to workforce development, and helping to ensure a future U.S.-based expertise in the fields of nuclear chemistry and radiochemistry.

NP Science Highlights

Explaining Light-Nuclei Production in Heavy-Ion Nuclear Collisions
Pairs of sub-atomic particles may catalyze reactions that happened moments after the Big Bang.
Learn More
Solving a Beta Decay Puzzle
Researchers use advanced nuclear models to explain 50-year mystery surrounding the process stars use to transform elements.
Learn More
STAR Gains Access to “Wimpy” Quarks and Gluons
Low-momentum (wimpy) quarks and gluons contribute to proton spin, offering insights into protons’ behavior in all visible matter.
Learn More
Improving Isotope Supply for a Cancer-Fighting Drug
Production of actinium-227 ramps up for use in a drug to fight prostate cancer that has spread to bone.
Learn More
Why Are These Extremely Light Calcium Isotopes So Small?
The radii of three proton-rich calcium isotopes are smaller than previously predicted because models didn’t account for two nuclear interactions.
Learn More
Extracting Signs of the Elusive Neutrino
Scientists use software to "develop" images that trace neutrinos' interactions in a bath of cold liquid argon.
Learn More
Spin Flipper Upends Protons
The spin of high-energy proton beams is strongly coupled to their orbit direction: a one-degree orbit deflection will also rotate the spin of a 255
Learn More
Sea Quark Spin Surprise!
Since the 1980s, scientists have known that quark and antiquark spins within a proton account for, at best, a quarter of the overall proton spin.
Learn More
The Weak Side of the Proton
The weak force’s effects can be observed in our everyday world: it initiates the chain of reactions that power the sun, and it provides a
Learn More
Fast-Moving Pairs May Solve 35-Year-Old Mystery
The European Muon Collaboration discovered the EMC Effect in data taken at CERN. The collaboration found that quarks inside a nucleus appeared
Learn More

NP Program News

Sea Quark Surprise Reveals Deeper Complexity in Proton Spin Puzzle
New data from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC) add detail—and complexity—to an intriguing puzzle that scientists have been seeking to solve: how the building blocks that make up a proton contribute to its spin. The results, just published as a rapid communication in the journal Physical Review D, reveal definitively for the first time that different “flavors” of antiquarks contribute differently to the proton’s overall spin—and in a way that’s opposite to those flavors’ relative abundance.
Learn More
Jefferson Lab Particle Accelerator Quality Testing Facility Is Going Stronger Than Ever After 5,000 Tests
Thirty years ago, a newly assembled team of scientists, engineers and technicians set out to build the world’s first automated test and qualification facility for superconducting radiofrequency, or SRF, accelerator components. Today, the Vertical Test Area at the Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab’) is still going strong, more than 5,000 SRF accelerator component tests later.
Learn More
Researchers Examine Puzzling Sizes of Extremely Light Calcium Isotopes
Michigan State University researchers have measured for the first time the nuclei of three proton-rich calcium isotopes, according to a new paper publ
Learn More


Contact Information

Nuclear Physics
U.S. Department of Energy
SC-26/Germantown Building
1000 Independence Avenue., SW
Washington, DC 20585
P: (301) 903 - 3613
F: (301) 903 - 3833
E: Email Us

More Information »