Electric dipole moment searches using storage rings
Frank Rathmann, Nikolai N. Nikolaev
备注:
15 pages, 9 figures, contribution for the 23rd International Spin Physics Symposium (SPIN 2018), 10-14 September, 2018, Ferrara, Italy. To be published in the Proceedings of Science (PoS)
粒子物理学的标准模型(SM)无法解释我们宇宙中物质-反物质的明显不对称性。需要超出SM的物理,并且通过采用最高能量(例如,在LHC),或通过努力达到最终的精度和灵敏度(例如,在寻找电偶极矩中)。粒子的永久电偶极矩(EDM)违反时间反演$(T)$和宇称$(P)$不变性,并且通过$CPT$定理也违反$CP$。发现EDM将是SM之外物理学的一个强有力的指示,并且推动上限进一步为任何相应的理论模型提供了关键的测试,例如,超对称性到目前为止,EDM的研究主要集中在中性系统(中子、原子和分子)上。然而,储存环提供了通过观察EDM对环中自旋运动的影响来测量带电粒子的EDM的可能性。然而,质子和氘EDM的直接搜索具有达到超过$10^{-29}$ e $\cdot$ cm的灵敏度的潜力。由于位于于利希研究中心的冷却器同步加速器COSY提供了高达3.7 GeV/c动量的极化质子和氘核,它构成了这样一个实验计划的理想试验场和起点。除了讨论JEDI合作的成就,以及在COSY进行第一次直接氘EDM测量的努力之外,报告还强调了未来的技术发展,这将为专用环中的EDM搜索铺平道路。JEDI成功工作的最新进展是CPEDM协作的形成,该协作旨在设计可在CERN或COSY托管的EDM原型环,我们也将讨论该环。
英文摘要:
The Standard Model (SM) of Particle Physics is not capable to account for the apparent matter-antimatter asymmetry of our Universe. Physics beyond the SM is required and is either probed by employing highest energies (e.g., at LHC), or by striving for ultimate precision and sensitivity (e.g., in the search for electric dipole moments). Permanent electric dipole moments (EDMs) of particles violate both time reversal $(T)$ and parity $(P)$ invariance, and are via the $CPT$-theorem also $CP$-violating. Finding an EDM would be a strong indication for physics beyond the SM, and pushing upper limits further provides crucial tests for any corresponding theo\-retical model, e.g., SUSY. Up to now, EDM searches focused on neutral systems (neutrons, atoms, and molecules). Storage rings, however, offer the possibility to measure EDMs of charged particles by observing the influence of the EDM on the spin motion in the ring. Direct searches of proton and deuteron EDMs, however, bear the potential to reach sensitivities beyond $10^{-29}$ e$\cdot$cm. Since the Cooler Synchrotron COSY at the Forschungszentrum Jülich provides polarized protons and deuterons up to momenta of 3.7 GeV/c, it constitutes an ideal testing ground and starting point for such an experimental program. Besides the discussion of the achievements of the JEDI collaboration, and the description of an effort to perform a first direct deuteron EDM measurement at COSY, the report highlights in addition future technical developments that will pave the way toward EDM searches in dedicated rings. A recent advancement that grew out of the successful work performed by JEDI is the formation of the CPEDM Collaboration, which aims at the design of an EDM prototype ring that could be hosted either at CERN or at COSY, will be discussed as well.
Electric dipole moment searches: Effect of linear electric field frequency shifts induced in confined gases, II
下一代粒子电火花加工搜索将具有如此高的灵敏度,以至于结果可能会受到由运动(E x v/c)磁场与杂散场梯度相互作用引起的系统误差的污染。本文扩展了前人的工作,给出了矩形贮液容器情况下的频移解析表达式,并讨论了该结果对LANL合作组将在SNS(Spanish Neutron Source)上进行的中子EDM实验的意义
Detailed discussion of a linear electric field frequency shift (important for next generation) electric dipole moment searches) induced in confined gases by a magnetic field gradient: Implications for electric dipole moment experiments (II)
寻找粒子电偶极矩是寻找标准模型之外的物理的最有前途的途径。许多研究小组正在计划使用各种储存气体进行新一代实验。为了达到目标灵敏度,有必要处理由众所周知的E x v场与磁场梯度的相互作用(通常称为几何相位效应[9,10])产生的系统误差。这种相互作用在电场中产生线性频移,模仿电火花加工。在这项工作中,我们介绍了一个分析模型的关联函数,它决定了频移的行为[11],并详细说明它如何取决于实验的操作条件。我们还提出了一种在给定实验条件下直接测量关联函数的方法。
Linear electric field frequency shift (important for next generation electric dipole moment searches) induced in confined gases by a magnetic field gradient
Community input to the European Strategy on particle physics: Searches for Permanent Electric Dipole Moments
Imperial College London(帝国理工学院);CERN, Geneva, Switzerland(欧洲核子研究中心);University of Marburg, Germany(马尔堡大学);Heidelberg University, Germany(海德堡大学);University of Amsterdam, The Netherlands(阿姆斯特丹大学);University of Groningen, The Netherlands(格罗宁根大学);University of Manchester, United Kingdom(曼彻斯特大学);University of Milan and INFN Milan, Italy(米兰大学与意大利国家核物理研究所米兰分部);Paul Scherrer Institute, Villigen, Switzerland(保罗谢尔研究所);U. Bern, Switzerland(伯尔尼大学);U. Bonn, Germany(波恩大学);KAIST, Daejeon, Korea(韩国科学技术院);Technical University of Munich, Germany(慕尼黑工业大学);U. Valencia and IFIC, Spain(瓦伦西亚大学与伊比利亚原子核物理联合研究所);LAC Orsay, France(奥赛低能原子核物理实验室);INFN Padua, Italy(意大利国家核物理研究所帕多瓦分部);INFN Pisa, Italy(意大利国家核物理研究所比萨分部);U. Sussex, UK(萨塞克斯大学);ILL, Fra(法国高斯朗热实验室)
Geometric phases in electric dipole searches with trapped spin-1/2 particles in general fields and measurement cells of arbitrary shape with smooth or rough walls
Microscopic study of low-lying states in odd-mass nuclei for atomic electric dipole moment searches
School of Physics and Astronomy, Sun Yat-sen University(中山大学物理学院);Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing, Sun Yat-Sen University(中山大学广东省量子计量与传感重点实验室)
Demonstration of sensitivity increase in mercury free-spin-precession magnetometers due to laser-based readout for neutron electric dipole moment searches
Storage Ring to Search for Electric Dipole Moments of Charged Particles -- Feasibility Study
所提出的方法利用带电粒子限制为一个存储环束(质子,氘核,可能$^3$他)搜索沿粒子自旋轴排列的固有电偶极矩(EDM)。统计灵敏度可接近10 $^{-29}$ e $\cdot$ cm。挑战将是将系统误差减少到类似的水平。将调整环以保持自旋极化,最初平行于粒子速度,时间超过15分钟。通过EDM作用的大径向电场将使极化从纵向旋转到垂直方向。垂直偏振分量的缓慢上升,通过从目标散射检测,信号EDM。该项目的战略是概述。设想了一个逐步的计划,从正在进行的COSY活动开始,这些活动证明了技术可行性。迄今为止的成就包括减少偏振测量误差,长的水平面偏振寿命,并通过散射测量的反馈控制偏振方向。该项目继续进行能力验证测量(前体实验;第一次直接氘EDM测量),中间原型环(原理验证;关键技术演示),最后是高精度电场存储环。
Potential for measurement of the tensor electric and magnetic polarizabilities of the deuteron in storage-ring experiments with polarized beams
测量氘核的张量极化率和张量极化率是非常有意义的,特别是与COSY和GSI的可能性有关。这些极化率可以通过提供g-2旋进消失的冻结自旋方法在储存环中测量。该方法将用于计划中的储存环氘电偶极矩实验。在上述实验中,氘核的张量极化率显著影响垂直极化的建立。自旋相互作用依赖于电偶极矩,张量极化率,和场失调引起的主要系统误差具有非常不同的对称性。对于所考虑的实验条件,$1\times10^{-29} e\cdot$ cm对氘EDM的灵敏度对应于以$δα_T\approxδβ_T\approx5\times10^{-42}$ cm $^3$的精度测量两个张量极化率。这种保守估计可以通过排除由场不稳定性引起的系统误差来改善,因为场不稳定性对于张量极化率的测量是可以忽略的。为了得到张量磁极化率,需要测量极化矢量的水平分量。