标题： 关于核钟对新物理的敏感性 显示英文标题

标题： On the sensitivity of nuclear clocks to new physics

摘要： 最近展示的钍-229$\approx 8$电子伏特同质异能态的激光激发是迈向原子核钟的重要一步。 低激发能量可能是电磁力和强相互作用贡献之间抵消的结果。 超出标准模型的物理可能会破坏这种抵消，突显原子核钟对新物理的敏感性。 对核跃迁能量的不同贡献的准确预测，以及因此对原子核钟定量敏感性的预测，具有挑战性。 我们改进了以前的敏感性估计，并评估了一个“噩梦场景”，其中所有结合能差异都很小，新物理的敏感性较差。 钍-229的经典几何模型表明，对于这种场景需要精细调整。 我们还提出了一种$d$波晕模型，受有效场论的启发。 我们证明它能够再现观测结果，并表明“噩梦场景”不太可能。 我们发现原子核钟对有效精细结构常数变化的敏感性增强了大约$10^4$倍。 最后，我们提出了辅助的核测量方法，以减少不确定性并进一步验证晕模型的有效性。 显示英文摘要

摘要： The recent demonstration of laser excitation of the $\approx 8$ eV isomeric state of thorium-229 is a significant step towards a nuclear clock. The low excitation energy likely results from a cancellation between the contributions of the electromagnetic and strong forces. Physics beyond the Standard Model could disrupt this cancellation, highlighting nuclear clocks' sensitivity to new physics. Accurate predictions of the different contributions to nuclear transition energies, and therefore of the quantitative sensitivity of a nuclear clock, are challenging. We improve upon previous sensitivity estimates and assess a ''nightmare scenario'', where all binding energy differences are small and the new physics sensitivity is poor. A classical geometric model of thorium-229 suggests that fine-tuning is needed for such a scenario. We also propose a $d$-wave halo model, inspired by effective field theory. We show that it reproduces observations and suggests the ''nightmare scenario'' is unlikely. We find that the nuclear clock's sensitivity to variations in the effective fine structure constant is enhanced by a factor of order $10^4$. We finally propose auxiliary nuclear measurements to reduce uncertainties and further test the validity of the halo model.