The 3-D stochastic cooling has been implemented in RHIC for the first time in the 2012 heavy ion run. In the U-U run, the U beam's transverse emittances were cooled from initially about 13.5 mm.mrad down to 2.5 mm.mrad. The beam-beam parameters reached a maximum of-0.005. In the Cu-Au run, due to the unbalanced transverse beam sizes of the Cu and Au beams in the first several hours at the store, the Cu beam lifetime was significantly reduced by the beam-beam interaction. To maintain the Cu beam lifetime and to maximize the integrated luminosity, we intentionally reduced the cooling rate for the Au beam until the Cu beam got cooled. In this article, we review the beambeam effects in the 2012 RHIC heavy ion run and carry out numerical simulations to interpret the observations.

In this article we will re-visit the local coupling correction in the interaction regions (IRs) of the Relativistic Heavy Ion Collider (RHIC). We will review the measurement data of triplet quadrupole rolls, the local coupling correction strengths in the RHIC control system, and the methods for the local coupling correction with local skew quadrupole correctors. Based on the in-turnnel meaurement data of triplet roll errors in 2011, we will analytically calculate and simulate IR-bump method to find out the local skew correction strengths and compare them at store and at injection with the Blue and Yellow ring lattices in the 2011 polarized proton (p-p) and Au-Au runs. The vertical dispersion from the triplet roll errors, local and global coupling correction skew quadrupoles, and the vertical dipole correctors are calculated and discussed.