Experimental Demonstration of a Large Transverse Emittance Ratio 11∶1 in the Relativistic Heavy Ion Collider for the Electron-Ion Collider.

The Electron-Ion Collider (EIC), to be constructed at Brookhaven National Laboratory, will collide polarized high-energy electron beams with hadron beams, achieving luminosities of up to 1.0×10^{34}  cm^{-2} s^{-1} in the center-of-mass energy range of 20-140 GeV. To achieve such high luminosity, the EIC will employ small and flat beams at the interaction point.

Experimental Demonstration of Hadron Beam Cooling Using Radio-Frequency Accelerated Electron Bunches.

Cooling of beams of gold ions using electron bunches accelerated with radio-frequency systems was recently experimentally demonstrated in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Such an approach is new and opens the possibility of using this technique at higher energies than possible with electrostatic acceleration of electron beams. The challenges of this approach include generation of electron beams suitable for cooling, delivery of electron bunches of the required quality to the cooling sections without degradation of beam angular divergence and energy spread, achieving the required small angles between electron and ion trajectories in the cooling sections, precise velocity matching between the two beams, high-current operation of the electron accelerator, as well as several physics effects related to bunched-beam cooling.

A storage ring experiment to detect a proton electric dipole moment.

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of 10 e ⋅ cm by using polarized "magic" momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented.

Three-dimensional stochastic cooling in the relativistic heavy ion collider.

Three-dimensional stochastic cooling of 100  GeV/nucleon gold beams has been achieved in the Relativistic Heavy Ion Collider (RHIC). We discuss the physics and technology of the cooling systems and present results with a beam. A factor of 2 increase in luminosity was achieved and another factor of 2 is expected.

Dynamics of ion shielding in an anisotropic electron plasma.

We show that, for a test ion moving in a collisionless single-species electron plasma, exact analytical solutions can be obtained for certain anisotropic velocity distributions of the electron plasma. By comparing the analytical formula with the numerical results calculated for the more realistic Maxwellian plasma, we demonstrate that plasmas with three different velocity distributions behave similarly for ions moving with velocity smaller than the velocity spread of the electrons. Furthermore, we show that the response of the electron density to a rest ion decays exponentially with distance, provided the anisotropic velocity distribution exhibits elliptical symmetry.