New Method Could Explore Gluon Saturation at the Future Electron-Ion Collider

Exploring the gluon saturation in large nuclei is one of the major goals of the future Electron-Ion Collider. New research proposes a novel method to probe the onset of gluon saturation by measuring the nucleon energy-energy correlation in deep inelastic scattering. This result leads to a comprehensive approach to study the universal behavior of gluon saturation.

João Barata Awarded CERN Fellowship

João Barata, a physicist in the Nuclear Theory Group at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, has received a fellowship at CERN, the European Organization for Nuclear Research. In October 2024, Barata will begin the three-year-long appointment in CERN’s Department of Theoretical Physics.

Argonne National Laboratory set to play pivotal role in realizing U.S. goals for nuclear science research

The Nuclear Science Advisory Committee recently unveiled its 2023 Long Range Plan for nuclear science. Argonne National Laboratory, with its world-class nuclear physics facilities and expertise, is poised to play a pivotal role in realizing the plan.

Jefferson Lab Welcomes Next Generation of Nuclear Physicists

The U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility is proud to announce nine new graduate fellowships for the 2023-2024 academic year, thanks to ongoing funding from Jefferson Science Associates. These fellowships offer students a unique opportunity to collaborate with leading nuclear physicists at Jefferson Lab and pursue advanced studies at their respective universities.

Exploring Stellar Hydrogen Burning via Muons and Nuclei

When a muon binds with a deuteron, it forms a system with two neutrons in a process analogous to proton-proton fusion. Nuclear theorists examined this muon capture process to quantify theoretical uncertainty relevant for comparison with experimental data and to test predictions involving proton-proton fusion. The study supports ongoing efforts to enhance the accuracy of muon capture measurements and to apply the same theoretical framework to other processes.

Department of Energy Announces up to $500 Million for Basic Research to Advance the Frontiers of Science

The U.S. Department of Energy (DOE) today announced up to $500 million in funding for basic research in support of DOE’s clean energy, economic, and national security goals.

Department of Energy Announces $73 Million for Basic Research to Accelerate the Transition from Discovery to Commercialization

Today, the U.S. Department of Energy (DOE) announced $73 million in funding for eleven projects which focus on the goal of accelerating the transition from discovery to commercialization of new technologies that will form the basis of future industries.

Scientists Make the First Observation of a Nucleus Decaying into Four Particles After Beta Decay

Scientists have observed a rare new radioactive decay mode for the first time. In this decay mode, oxygen-13 (with eight protons and five neutrons) decays by breaking into three helium nuclei (an atom without the surrounding electrons), a proton, and a positron (the antimatter version of an electron) following beta decay. The findings expand scientific knowledge of decay processes and the properties of the nucleus before the decay.

Theoretical and Experimental Physics Team Up in the Search for Particle Flavor Change

Scientists recently discovered that neutrinos have mass, counter to long-held understanding. This means that neutrinos can change flavor. Now, advances in theory and experiment are helping scientists to determine whether the neutrinos’ charged counterparts—electrons, muons, and tauons—can also change flavor and how future experiments can look for those changes.

DOE Awards $135 Million For Groundbreaking Research By 93 Early Career Scientists

The U.S. Department of Energy (DOE) today announced the selection of 93 early career scientists from across the country who will receive a combined $135 million in funding for research covering a wide range of topics, from artificial intelligence to astrophysics to fusion energy. The 2023 Early Career Research Program awardees represent 47 universities and 12 DOE National Laboratories across the country. These awards are a part of the DOE’s long-standing efforts to develop the next generation of STEM leaders to solidify America’s role as the driver of science and innovation around the world.

Discovering Evidence of Superradience in the Alpha Decay of Mirror Nuclei

Nuclei can absorb energy, pushing the nuclei into excited states. When these states decay, the nuclei emit different particles. The interplay between these decay channels and the internal characteristics of the excited states gives rise to phenomena such as superradiance. In superradiance, a nucleus with high excitation energy has excited states so dense that neighboring excited states overlap. Scientists recently found evidence of the superradiance effect in the differences between decaying states in Oxygen-18 and Neon-18.

New Driver for Shapes of Small Quark-Gluon Plasma Drops?

New measurements of how particles flow from collisions of different types of particles at the Relativistic Heavy Ion Collider (RHIC) have provided new insights into the origin of the shape of hot specks of matter generated in these collisions. The results may lead to a deeper understanding of the properties and dynamics of this form of matter, known as a quark-gluon plasma (QGP).

Direct Photons Point to Positive Gluon Polarization

A new publication by the PHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC) provides definitive evidence that gluon “spins” are aligned in the same direction as the spin of the proton they’re in. The result, just published in Physical Review Letters, provides theorists with new input for calculating how much gluons—the gluelike particles that hold quarks together within protons and neutrons—contribute to a proton’s spin.

STAR Physicists Track Sequential ‘Melting’ of Upsilons

Recent data from the Relativistic Heavy Ion Collider show how three distinct variations of particles called upsilons “melt,” or dissociate, in the hot particle soup that existed in the very early universe. The results from the STAR experiment support the theory that this hot matter is a soup of “free” quarks and gluons. Measuring how different upsilons dissociate helps scientists learn about the quark-gluon plasma.

Calculation Shows Why Heavy Quarks Get Caught up in the Flow

Theorists have calculated how quickly a melted soup of quarks and gluons—the building blocks of protons and neutrons—transfers its momentum to heavy quarks. The calculation will help explain experimental results showing heavy quarks getting caught up in the flow of matter generated in heavy ion collisions.

Precision Nuclear Physics in Indium-115 Beta Decay Spectrum using Cryogenic Detectors

Nuclei such as Indium-115 (In-115) are extremely long lived, with half-lives of more than 100 billion years. These nuclei allow scientists to probe elusive high energy nuclear states. In a new study, scientists theoretically determined the electron energy spectrum from decays of In-115 based on data collected in a specialized detector. The scientists also performed the world’s most precise measurement of the half-life of In-115.

A Simple Solution for Nuclear Matter in Two Dimensions

Understanding the behavior of nuclear matter is extremely complicated, especially when working in three dimensions. Mathematical techniques from condensed matter physics that consider interactions in just one spatial dimension (plus time) greatly simplify the problem. Using this two-dimensional approach, scientists solved the complex equations that describe how low-energy excitations ripple through a system of dense nuclear matter such as exists at the center of neutron stars.

Resolving a Mathematical Puzzle in Quarks and Gluons in Nuclear Matter

Theoretical calculations involving the strong force are complex in part because of the large number of ways these calculations can be performed. These options include “gauge choices.” All gauge choices should produce the same result for the calculation of any quantity that can be measured in an experiment. However, it is difficult to obtain consistent results when using one particular choice, “axial gauge.” New research resolves this puzzle.

New Insights on the Interplay of Electromagnetism and the Weak Nuclear Force

Outside atomic nuclei, neutrons are unstable, disintegrating in about fifteen minutes due to the weak nuclear force to leave behind a proton, an electron, and an antineutrino. New research identified a shift in the strength with which a spinning neutron experiences the weak nuclear force, due to emission and absorption of photons and pions. The finding impacts high precision searches of new, beyond the Standard Model interactions in beta decay.

Subtle Signs of Fluctuations in Critical Point Search

Physicists analyzing data from gold ion smashups at the Relativistic Heavy Ion Collider (RHIC), a U.S. Department of Energy (DOE) Office of Science user facility for nuclear physics research at DOE’s Brookhaven National Laboratory, are searching for evidence that nails down a so-called critical point in the way nuclear matter changes from one phase to another.

A Holographic View into Quantum Anomalies

Theorists calculated how the key ingredients of a phenomenon called the chiral magnetic effect should evolve over time in an expanding quark-gluon plasma. The theorists used the holographic principle to model the magnetic fields and other relevant characteristics needed for the effect. The results will help scientists interpret collision data and plan new searches for the chiral magnetic effect and the underlying quantum anomaly.

RHIC Gets Ready to Smash Gold Ions for Run 23

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, known as sPHENIX, will track what happens when the nuclei of gold atoms smash into one another at nearly the speed of light. RHIC’s STAR detector, which has been running and evolving since 2000, will also see some firsts in Run 23.

Jefferson Lab Hosts International Computing in High Energy and Nuclear Physics Conference

Experts in high-performance computing and data management are gathering in Norfolk next week for the 26th International Conference on Computing in High Energy and Nuclear Physics (CHEP2023). Held approximately every 18 months, this high-impact conference will be held at the Norfolk Marriott Waterside in Norfolk, Va., May 8-12. CHEP2023 is hosted by the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility in nearby Newport News, Va. This is the first in-person CHEP conference to be held since 2019.

EIC Center at Jefferson Lab Announces Six Research Fellowship Awards

The Electron-Ion Collider Center at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility (EIC Center at Jefferson Lab) has announced the winners of six new research fellowships. Over the next year, the fellows will work to advance the science program and further the research of the Electron-Ion Collider (EIC). The EIC is a unique physics research facility dedicated to answering fundamental questions about nature’s building blocks.

sPHENIX Detector is Ready for Collisions

The state-of-the-art sPHENIX detector is fully assembled and gearing up to grab particle collision snapshots. The completion of assembly marks the detector’s transition from a construction project to running experiment at the Relativistic Heavy Ion Collider (RHIC), a U.S. Department of Energy Office of Science user facility for nuclear physics research at Brookhaven National Laboratory.

Understanding the Origin of Matter with the CUORE Experiment

Neutrinos are involved in a process named beta decay that involves a neutron converting into a proton emitting an electron and an antineutrino. There may also be an ultra-rare kind of beta decay that emits two electrons but no neutrinos, called neutrinoless-double beta decay (NLDBD). Researchers are using the Cryogenic Underground Observatory for Rare Events (CUORE) to search for these rare NLDBD processes using different nuclei. Scientists have reported new tests using Tellurim-128 to look for NLDBD.

Nucleons in Heavy Ion Collisions Are Half as Big as Previously Expected

To understand quark-gluon plasma, theorists compare a sophisticated model to a large amount of experimental data. One of the parameters in this model is the size of the nucleons inside the two colliding lead nuclei. Low-energy experiments find a nucleon size of around 0.5 femtometers, while heavy ion experimental data have found a much larger nucleon size, of about 1 femtometers. A new analysis of heavy ion experimental data includes the experimentally measured reaction rate of lead-lead collisions to arrive at a nucleon size of 0.6 femtometers.

First Science Results from FRIB Published

A multi-institutional team of nuclear science researchers has published the results of the first experiment at the Facility for Rare Isotope Beams. The experiment involved colliding a beam of stable calcium-48 nuclei traveling at about 60 percent of the speed of light into a beryllium target to produce isotopes near the “drip line,” the spot where neutrons can no longer bind to a nucleus but instead drip off.

A Novel Way to Get to the Excited States of Exotic Nuclei

Researchers developed a novel approach that observes dissipative scattering reactions to investigate discrete energy levels in an excited exotic nucleus. These energy levels are the nucleus’ unique fingerprint. The researchers observed unusual excited levels in calcium-38. These levels appear to be due to the simultaneous excitation of several protons and neutrons.

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.

New Type of Entanglement Lets Scientists ‘See’ Inside Nuclei

Nuclear physicists have found a new way to see inside nuclei by tracking interactions between particles of light and gluons. The method relies on harnessing a new type of quantum interference between two dissimilar particles. Tracking how these entangled particles emerge from the interactions lets scientists map out the arrangement of gluons. This approach is unusual for making use of entanglement between dissimilar particles—something rare in quantum studies.

Imaging the Proton with Neutrinos

The interactions of the quarks and gluons that make up protons and neutrons are so strong that the structure of protons and neutrons is difficult to calculate from theory and must be instead measured experimentally. Neutrino experiments use targets that are nuclei made of many protons and neutrons bound together. This complicates interpreting those measurements to infer proton structure. By scattering neutrinos from the protons that are the nuclei of hydrogen atoms in the MINERvA detector, scientists have provided the first measurements of this structure with neutrinos using unbound protons.

Hitting Nuclei with Light May Create Fluid Primordial Matter

A new analysis supports the idea that photons colliding with heavy ions create a fluid of “strongly interacting” particles. The results indicate that photon-heavy ion collisions can create a strongly interacting fluid that responds to the initial collision geometry and that these collisions can form a quark-gluon plasma. These findings will help guide future experiments at the planned Electron-Ion Collider.

Laser shots at National Ignition Facility could spark additional discoveries in astrophysics

Using the Argonne Tandem Linac Accelerator System (ATLAS), a team of scientists is studying the environment created during laser shots at the National Ignition Facility to better understand its potential as a testbed for nuclear astrophysics research.

Clear Sign that QGP Production ‘Turns Off’ at Low Energy

Physicists report new evidence that production of an exotic state of matter in collisions of gold nuclei at the Relativistic Heavy Ion Collider (RHIC) can be ‘turned off’ by lowering the collision energy. The findings will help physicists map out the conditions of temperature and density under which the exotic matter, known as a quark-gluon plasma (QGP), can exist and identify key features of the phases of nuclear matter.