Tracking and Particle ID
• If central region of RHIC
collisions has zero net
baryon number
• Particle ID
• TOF wall
• dE/dx in silicon
• Two B-field settings
• Many systematic effects
cancel in the ratio
•     For spectrometer performance, see talk by K. Gulbrandsen, MIT
•     For TOF performance, see talk by E. Johnson, U of Rochester