PROSPECT Characterizes the Footprint of Neutrinos

Predictions based on the Standard Model of particle physics don’t always agree with what scientists see in experimental data. One way to examine these differences is emissions of neutrinos from nuclear reactors. As part of this research agenda, scientists in the PROSPECT Collaboration have reported the most precise measurement ever of the energy spectrum of antineutrinos emitted from the fission of uranium-235, providing a new reference energy spectrum and new constraints on the origin of the disagreements between data and models.

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.

Precise Measurement of Pions Confirms Understanding of Fundamental Symmetry

Scientific rules about “chiral symmetry” predict the existence of subatomic particles called pions. The lifetime of a neutrally charged pion is tied to breaking of chiral symmetry. Until recently, measurements of this lifetime have been much less precise than calculations from theory. Physicists have now measured a pion’s lifetime more precisely than ever before.

Searching for Signs of ‘Glueballs’ in Proton-Proton Smashups

In principle, the universe should contain objects composed only of gluons in a sea of quark-antiquark pairs. However, scientists’ experiments have never definitively confirmed these hypothetical objects, called “glueballs.” Now, scientists are using the Relativistic Heavy Ion Collider to search for signs of these glueballs.

Scientists achieve higher precision weak force measurement between protons, neutrons

Through a one-of-a-kind experiment at Oak Ridge National Laboratory, nuclear physicists have precisely measured the weak interaction between protons and neutrons. The result quantifies the weak force theory as predicted by the Standard Model of Particle Physics.

New Calculation Refines Comparison of Matter with Antimatter

An international collaboration of theoretical physicists has published a new calculation relevant to the search for an explanation of the predominance of matter over antimatter in our universe. The new calculation gives a more accurate prediction for the likelihood with which kaons decay into a pair of electrically charged pions vs. a pair of neutral pions.

Another Win for the Standard Model: New Study Defies Decades-Old ‘Discrepancy’ With High-Precision Measurement

A new study dives into a decades-old discrepancy from a Standard Model of particle physics pillar known as “lepton flavor universality,” and provides strong evidence to resolve it.