BNL, Upton, Long Island, New York
In this article we will review the computational challenges in the beam-beam simulation for the polarized proton run of the Relativistic Heavy Ion Collider (RHIC). The difficulties in our multi-particle and million turn tracking to simulate the proton beam lifetime and proton beam emittance growth due to head-on beam-beam interaction and head-on beam-beam compensation are presented and discussed. Soultions to obtain meaning physics results from these trackings are proposed and tested. In the end we will report the progress in the benchmarking of the RHIC operational proton beam lifetime.
BNL, Upton, Long Island, New York
There is a strong interest in heavy-ion collisions at the center of mass energies of 5-20 GeV/nucleon. This physics program is motivated by a search of the QCD phase transition critical point. Such low-energy operations started at Relativistic Heavy Ion Collider (RHIC) in 2010. The defining limitation in luminosity improvement for this program is expected to be due to the space charge. For RHIC, we are interested in rather long beam lifetime, which sets limitation on an allowable space-charge tune shift. An additional complication comes from the fact that ion beams are colliding, which requires careful consideration of the interplay of direct space-charge and beam-beam effects. We started to explore these beam dynamics effects in RHIC Accelerator Physics Experiments (APEX) in 2009 with proton beams. The experiments continued in 2010 with Au ion beams. This paper summarizes our findings and observations.