Collaborative Research: PM: CeNTREX, A Search for Nuclear Time-Reversal Symmetry Violation with Quantum-State-Controlled TlF Molecules

基本对称性是我们理解物理世界的核心。 特别是，时间反演（T）对称性的小尺度破坏对于解释观察到的物质相对于反物质的优势是必要的，这是现代科学中最基本的问题之一。 新的T-违反物理学很可能是由具有大质量的粒子介导的，这些粒子的质量超过了目前高能加速器的范围。 该实验将对核希夫矩进行高精度搜索，这是铊（Tl）核中的电荷分离，这将标志着T破坏。 检测到灵敏度超过最佳电流极限的希夫矩将为超越标准模型的物理学提供明确的证据，而零测量将对包括T违反来源的理论设置严格的约束，并可能确定未来粒子加速器的技术目标。 实验分子量子科学和理论核物理学将在这里结合起来，使用桌面实验和最先进的计算进行新的合作。 将使用氟化铊（TlF）极性分子来测量TlSchiff矩，所述氟化铊（TlF）极性分子在长相互作用区域中与所施加的电场对准。 希夫矩的存在将通过T1磁矩（自旋）关于所施加的场的进动来表现。 该项目将广泛影响技术和教育。 研究生和本科生将积极参与研究，获得在学术界，工业界和国家实验室高度重视的实践技能。 这项工作的结果预计将对媒体和公众产生强烈的吸引力，并将被广泛传播。该项目将分子量子科学技术应用于时间反演对称性（T）破坏的测量，作为冷分子核时间反演实验（CeNTREX）的一部分。 研究人员试图在对基本参数的灵敏度方面，将以前对原子核T破坏的测量提高近两个数量级。 这种精确度将有助于解决重大挑战，例如在宇宙中观察到的物质-反物质不对称性。 研究人员将使用一束冷TlF分子，以联合收割机T1对T破坏核希夫矩的固有高灵敏度，强极化分子内T1核处的大有效电场，以及用于控制单个分子量子态的最先进技术，包括用于激光冷却和高保真检测的光学循环。 同时，他们将通过发展现代核物理方法来解决解释测量的理论问题，以准确计算Schiff矩对潜在核子-核子相互作用的依赖性，并量化其不确定性。 这种测量将与其他正在进行的T破坏搜索具有智力协同作用;互补实验可以通过对基本参数的不同灵敏度来识别观察到的对称性破坏的来源。 该项目也是对大型强子对撞机（LHC）的补充，LHC准备探测新的高能粒子，并可能确定它们违反T的相互作用的性质。 当前奖项支持的测量依赖于分子量子态的长寿命相干叠加，并将通过TlF的精细量子态控制，超高精度光谱学（包括内部共磁测量），该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响审查标准。

Fundamental symmetries are at the heart of our understanding of the physical world. In particular, small-scale violations of the time-reversal (T) symmetry are necessary to explain the observed predominance of matter over antimatter, one of the most fundamental problems in modern science. New T-violating physics is likely to be mediated by particles with large masses that exceed the current reach of high-energy accelerators. This experiment will carry out a high-precision search for the nuclear Schiff moment, a charge separation in the thallium (Tl) nucleus, that would signal T-violation. Detecting a Schiff moment with a sensitivity exceeding the best current limit would provide clear evidence for physics beyond the Standard Model, while a null measurement would set a stringent constraint on theories that include sources of T violation, and potentially identify the technical goals for future particle accelerators. Experimental molecular quantum science and theoretical nuclear physics will be combined here in a new collaboration using table-top experiments and state-of-the-art calculations. The Tl Schiff moment will be measured using thallium fluoride (TlF) polar molecules that are aligned with an applied electric field in a long interaction region. The presence of a Schiff moment will be manifested by a precession of the Tl magnetic moment (spin) about the applied field. This project will broadly impact technology and education. Graduate and undergraduate students will be actively involved in research, acquiring hands-on skills that are highly valued in academia, industry, and national labs. The results of this work are expected to have a strong appeal to the media and members of the public, and will be widely disseminated.This project applies the techniques of molecular quantum science to a measurement of time-reversal symmetry (T) violation, as part of the Cold Molecule Nuclear Time Reversal Experiment (CeNTREX). The investigators seek to improve upon previous measurements of T violation in atomic nuclei by nearly two orders of magnitude in terms of sensitivity to fundamental parameters. This level of precision will help address grand challenges such as the observed matter-antimatter asymmetry in the universe. The investigators will use a beam of cold TlF molecules in order to combine the intrinsically high sensitivity of Tl to the T-violating nuclear Schiff moment, the large effective electric field at the Tl nucleus within strongly polarized molecules, and state-of-the-art techniques for controlling individual molecular quantum states including optical cycling for laser cooling and high-fidelity detection. In parallel, they will address the theoretical question of interpreting the measurement by developing modern methods of nuclear physics to accurately calculate the dependence of the Schiff moment on the underlying nucleon-nucleon interactions and to quantify its uncertainty. This measurement will have intellectual synergy with other ongoing T violation searches; complementary experiments can identify the source of an observed symmetry violation via their different sensitivities to fundamental parameters. This project is also complementary to the Large Hadron Collider (LHC) which is poised to detect new high-energy particles and potentially identify the nature of their T-violating interactions. The measurement supported by the current award relies on long-lived coherent superpositions of molecular quantum states, and will make an impact on quantum sensing with molecules via the meticulous quantum state control of TlF, ultrahigh-precision spectroscopy including internal co-magnetometry, and radiation pressure forces applied to novel systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.