AI 中文总结
本研究提出在质子EDM储存环中联合校正反向旋转双束流，可从轨道中恢复四极对准误差的对称分量，减少重复对准操作，弥补了单束流校正无法处理该分量的不足。
AI 中文摘要
在用于测量质子电偶极矩（EDM）的储存环中，几微米量级的四极透镜对准误差会通过几何（Berry）相位模拟出真实的EDM信号；当均方根对准误差为10微米时，虚假信号强度可达目标灵敏度1e-29 e-cm的一千倍。对准误差可分为反对称分量与对称分量：反对称分量会使闭合轨道发生畸变，可被束流位置监测器（BPM）观测到；对称分量的轨道特征则被强烈抑制，因此标准的单束流轨道校正仅能去除反对称分量。现有设计通过基于束流的对准（BBA）方法来处理对称分量，该方法有效但相对缓慢且具有侵入性。本研究通过辛几何束流与自旋跟踪模拟表明，联合校正两束反向旋转的束流可从轨道本身恢复出对称分量：对称分量由两束轨道的和携带，而两束轨道的差对此不敏感，单束流的校正强度远不足以恢复该分量。静态BPM偏移与该和中的对称对准误差存在简并性，因此本方案无法替代初始绝对对准操作；但由于漂移具有微分特性且偏移会相互抵消，在完成一次初始BBA校准后，连续的双束流校正可维持对准状态，减少了原始质子EDM方案所需的重复对准操作。
英文摘要
In the storage ring proposed to measure the proton electric dipole moment (EDM), quadrupole misalignments of a few microns mimic a genuine EDM through a geometric (Berry) phase; at a 10 micron rms misalignment the false signal is up to a thousand times the target sensitivity of 1e-29 e-cm. The misalignment splits into an antisymmetric component, which distorts the closed orbit and is visible to the beam-position monitors, and a symmetric component, whose orbit signature is strongly suppressed. Standard single-beam orbit correction therefore removes only the antisymmetric part. The proposed design reaches the symmetric one by beam-based alignment (BBA), which is effective but relatively slow and invasive. Using symplectic beam and spin tracking, we show that correcting the two counter-rotating beams jointly recovers the symmetric component from the orbit itself; it is carried by the sum of the two orbits, whereas their difference is blind and a single beam is far too weak to recover it. The static BPM offset is degenerate with the symmetric misalignment in this sum, so the scheme does not replace the initial absolute alignment. However, the drift is differential and the offset cancels, so continuous two-beam correction maintains the alignment after a single initial BBA calibration, reducing the repeated realignment required by the original proton EDM proposal.
Comments9 pages, 7 figures
