BNL trip  Goal of the BNL-FERMILAB- CERN collaboration  The codes  BB tune foot-prints  DA studies

Goal of the BNL-FERMILAB-CERN Collaboration  Benchmaking of the codes  Lifetrac  SixTrack  SimTrack  DA and Tune foot-prints in view of BB

The Codes I  Lifetrac (Fermilab)  Weak-strong BB code (e-p colliders 1995)  Non-equilibrium distributions ( )  conventional macro particle tracking code  Machine lattice 6D map + thin multipoles  Beta-functions from MAD-X TWISS  Thin multipoles from MAD-X  RF sinusoidal kick  First and second order chromaticity via additional deltap phase advance and “chromatic drifts” before and after IP.  6D Hirata of sliced head-on, parasitic are thin  Introduction of noise once per kick  10’000 particles 1e6-1e7 turns  better beam emittance and lifetime:  Averaging density distribution over simulation step (10’000 turns)  Weighted distribution with more particles in the tails  MPI with non-interacting nodes

The Codes II  Sixtrack  Traditional single particle element-by element code  Extended Hamiltonian (bad for extremely large deltap)  Symplectic treatment of thin and thick (second order) elements  full Ripken theory  6D extended Hirata BB formalism (Ripken)  Full differential algebra and NormalForm implementation a pre-PTC approach  Optimized for speed  Elaborate run environment for massive tracking runs

The Codes III  SimTrack (BNL)  C++ library  4 th order symplectic integrator  4d and 6d BB  Benchmark Tracy II and BBSIM  Many elements  Parameter change on the fly  RHIC Au run and BB head-on compensation  Particle loss  emittance growth & lifetime  Linked to Mathematica: SVD, polynominal fitting etc.

The Codes IV (issues)  Lifetrac  How well can the lattice approximation work compared to the real thing?  No tune foot-print available (work in progress)  Sixtrack  The thick lens part is presently not fully operational but can be easily replaced by going to thin mode  No plans for emittance growth nor lifetime  SimTrack  Thinlens lattice not fully readable  No BB crossing angle implemented   Compare Lifetrac and SixTrack for LHC case  Tune foor-prints for RHIC

Conclusions  The approximations of Lifetrac are not that bad  Tune foot-prints from Lifetrac are highly desirable and will come  Lattice and NL are reasonably well represented to trust lifetime and emittance growth (of course has to be tested separately)  SimTrack agrees well concerning tune foot-print but longterm tracking needed to check reliabilty  Experiments sorely missed!