Spin dynamics and polarization of stored beams

4 problems

• Storage-ring systematic errors at the proton EDM sensitivity goal

  Open

  A proton electric dipole moment would slowly tilt the spins of stored protons; stray fields and ring misalignments tilt them too, and must be suppressed below the tiny expected signal.

• Self-polarization for energy calibration at FCC-ee Z and WW energies

  Open

  Measuring a collider's beam energy to a part per million uses spins that line up by themselves through synchrotron radiation; at higher energies this alignment is weak and easily destroyed.

• Residual polarization loss of protons accelerated with Siberian snakes

  Open

  Even with special magnets that flip the spin each turn, protons accelerated to hundreds of GeV lose part of their polarization, for reasons not fully modeled.

• Maximal spin coherence time of stored hadron beams

  Open

  Particles with slightly different energies precess at slightly different rates, so a polarized beam slowly loses its common spin direction.