Crabbing schemes 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 polarized proton and ion beams, achieving luminosities of up to 1 × 10³4 cm^−2 s^−1 in the center-of-mass energy range of 20-140 GeV. Crab cavities will be used in both EIC rings to compensate for the geometric luminosity loss due to the large crossing angle of 25 mrad in the interaction region. For the baseline design, a local crabbing scheme is adopted for both EIC rings, where crab cavities will be installed on both sides of the interaction region, and the ideal horizontal phase advance between the interaction point and the crab cavities is 90 degrees. In this article, we will study the feasibility of using a global crabbing scheme for each EIC ring, and, in particular, the case where the crab cavities in the Electron Storage Ring (ESR) will not be available during the early EIC commissioning. In this scenario, we need to reduce the electron beam's beam-beam parameter to avoid electron loss during injection.