Science Highlights

The quark Sivers function describes much of the physics of how quarks are distributed in a proton whose rotation is perpendicular to its direction of motion. This function shows whether more quarks in the proton move to the right than to the left of the plane created by the proton’s velocity and the direction of the proton’s rotation (spin) axis. Scientists have found a new theoretical contribution to the Sivers function of the quarks carrying a small fraction of the proton’s momentum.

X-ray bursts occur on the surface of a neutron star as it absorbs material from a companion star. This absorption initiates a cascade of thermonuclear reactions that create atoms of heavy chemical elements on the surface of a neutron star. Researchers have directly measured one of these reactions, finding it to be four times higher than the previous direct measurement.

Tantalum superconducting material shows great promise for making qubits. When an oxide layer forms on the surface of tantalum, it can lead to quantum decoherence. In this study, researchers used scanning transmission electron microscopy (STEM) and computer modeling to investigate the structure of superconducting tantalum film. This helped them build an atomic-level understanding of the crystalline lattice of tantalum metal and the oxide that forms on its surface.