  Particle accelerators for high energy physics will generate TeV-scale
particle beams in large, multi-Km size machines colliding high brightness beams
at the interaction point [1-4]. The high luminosity in such machines is
achieved by producing very small asymmetric beam size at the interaction point,
with short durations to minimize beam-beam effects. Tuning energy, timing and
position of the beam for optimal performance will require high-precision
controls of amplitude and phase of high-frequency electromagnetic fields and
real-time processing of complex algorithms. The stability of the colliding
beams has a large impact on the collider's effective luminosity. Therefore, the
technology readiness level of diagnostic and control systems will be a major
consideration in the collider design. The technical requirements of such
systems depend on the specifics of beam parameters, such as transverse and
longitudinal dimensions, charge/pulse and beam pulse format, which are driven
by the accelerating technology of choice. While feedback systems with single
bunch position monitor resolution below 50 nm and latency <300 ns have been
demonstrated in beam test facilities, many advanced collider concepts make use
of higher repetition rates, brighter beams and higher accelerating frequencies,
and will require better performance, up to 1-2 order of magnitude, demanding
aggressive R&D to be able to deliver and maintain the targeted luminosity.
