Observation of a Second-Order Spin-Depolarizing Resonance

C. Ohmori; H. Sato; L. V. Alexeeva; V. A. Anferov; D. D. Caussyn; C. M. Chu; D. A. Crandell; S. E. Gladycheva; S-Q. Hu; A. D. Krisch; R. A. Phelps; S. M. Varzar; V. K. Wong; S. Y. Lee; T. Rinckel; P. Schwandt; F. Sperisen; E. J. Stephenson; B. von Przewoski; R. Baiod; A. D. Russell

doi:10.1103/PhysRevLett.75.1931

Observation of a Second-Order Spin-Depolarizing Resonance

C. Ohmori, H. Sato, L. V. Alexeeva, V. A. Anferov, D. D. Caussyn, C. M. Chu, D. A. Crandell, S. E. Gladycheva, S-Q. Hu, A. D. Krisch, R. A. Phelps, S. M. Varzar, V. K. Wong, S. Y. Lee, T. Rinckel, P. Schwandt, F. Sperisen, E. J. Stephenson, B. von Przewoski, R. Baiod, and A. D. Russell

Phys. Rev. Lett. 75, 1931 – Published 4 September 1995

Abstract

A recent experiment using a 160 MeV stored spin-polarized proton beam found clear evidence for a second-order intrinsic depolarizing resonance. With a 20% partial Siberian snake, we studied a first-order intrinsic depolarizing resonance; we then discovered and studied the second-order depolarizing resonance by changing both the horizontal and vertical betatron tunes. As expected, this second-order resonance is much weaker than the first-order resonance; it is probably due to sextupole fields plus coupling between the horizontal and vertical betatron oscillations caused by the 20% snake.