RuPAC 2006 - List of Authors

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Nikitin, S.A.

Paper	Title	Page
MOAP01	Influence of Errors in KEDR Detector Field Compensation on the Spin Tune Shift and the Beam Polarization Lifetime in VEPP-4M Collider at Energy of Tau Lepton Production Threshold S.A.Nikitin Budker Institute of Nuclear Physics, Novosibirsk, Russia At present the experiment on precision measurement of tau lepton mass at VEPP-4M storage ring-collider with KEDR detector using the resonant depolarization technique is in process. Polarized beams needed in this technique are injected from VEPP-3 booster storage ring. The beam energy in experiment is near tau production threshold (1777 MeV) where a vicinity of the spin integer resonance (1763 MeV) strongly amplifies an influence of various field imperfections on spin motion. In particular, a spin tune shift, related to the energy quantity not through a simple proportional law, appears. Beside, a depolarization processes become significant. A few percent difference from zero of the longitudinal magnetic field integral in KEDR is worth to be considered in this viewpoint. We have studied the effects of KEDR field compensation errors on an accuracy of beam energy calibration by spin precession frequency as well as on a "lifetime" of beam polarization in VEPP-4M. Results of special experiments are presented and discussed in comparison with the calculation.	150

Paper

Title

Page

Influence of Errors in KEDR Detector Field Compensation on the Spin Tune Shift and the Beam Polarization Lifetime in VEPP-4M Collider at Energy of Tau Lepton Production Threshold

S.A.Nikitin
Budker Institute of Nuclear Physics, Novosibirsk, Russia

At present the experiment on precision measurement of tau lepton mass at VEPP-4M storage ring-collider with KEDR detector using the resonant depolarization technique is in process. Polarized beams needed in this technique are injected from VEPP-3 booster storage ring. The beam energy in experiment is near tau production threshold (1777 MeV) where a vicinity of the spin integer resonance (1763 MeV) strongly amplifies an influence of various field imperfections on spin motion. In particular, a spin tune shift, related to the energy quantity not through a simple proportional law, appears. Beside, a depolarization processes become significant. A few percent difference from zero of the longitudinal magnetic field integral in KEDR is worth to be considered in this viewpoint. We have studied the effects of KEDR field compensation errors on an accuracy of beam energy calibration by spin precession frequency as well as on a "lifetime" of beam polarization in VEPP-4M. Results of special experiments are presented and discussed in comparison with the calculation.

150