近日，德国杜塞尔多夫实验物理研究所S. Schiller团队研究了H₂⁺的高精度激光光谱和质子-电子质量比。这一研究成果发表在2025年8月6日出版的《自然》杂志上。

分子氢离子（MHI）是三体系统，适合在以下几个领域提高人们对其知识：基本常数、量子物理的测试、寻找新的粒子间力、弱等效原理的测试，一旦反分子ppe+可用，新的电荷偶对-时间反转不变性和局部位置不变性的测试。为了实现这些目标，需要对几种同位素物，特别是氢+2进行高精度的激光光谱分析。

研究组报道了氢分子离子（H₂⁺）振转能级跃迁的无多普勒激光光谱实验，实现了高达 2.2 × 10¹³ 的谱线分辨率。他们精确测定了该跃迁频率，其相对不确定度达到 8 × 10^-12。还测定了其自旋-转动耦合系数，不确定度为 0.1 kHz，该值与最新的理论预测值一致。综合研究组的理论和实验 H₂⁺ 数据，他们推得质子-电子质量比（m_d/m_p）的新数值。该数值与质谱法测得的值相符，且不确定度降低了 2.3 倍。

结合 MHI（分子氢离子）、H/D（氢/氘）及 μ 子 H/D 数据，研究组以 1.1 × 10^-10的绝对不确定度测定了重子质量比（m_d/m_p）。该数值与直接测量的质量比一致。最后，研究组展示了一个理论预测值与实验结果之间的吻合，其相对不确定度为 8.1 × 10^-12。这两项结果显著地证实了量子理论的预测能力，并在这些精度水平上未发现超出标准模型的新物理效应。

附：英文原文

Title: High-accuracy laser spectroscopy of  H+2 and the proton–electron mass ratio

Author: Alighanbari, S., Schenkel, M. R., Korobov, V. I., Schiller, S.

Issue&Volume: 2025-08-06

Abstract: The molecular hydrogen ions (MHI) are three-body systems suitable for advancing our knowledge in several domains: fundamental constants, tests of quantum physics, search for new interparticle forces, tests of the weak equivalence principle1 and, once the anti-molecule ppe+ becomes available, new tests of charge–parity–time-reversal invariance and local position invariance1,2,3. To achieve these goals, high-accuracy laser spectroscopy of several isotopologues, in particular H+2, is required4. Here we present a Doppler-free laser spectroscopy of a H+2 rovibrational transition, achieving line resolutions as large as 2.2×1013. We accurately determine the transition frequency with 8×1012 fractional uncertainty. We also determine the spin–rotation coupling coefficient with 0.1kHz uncertainty and its value is consistent with the state-of-the-art theory prediction5. The combination of our theoretical and experimental H+2 data allows us to deduce a new value for the proton-electron mass ratio mp/me. It is in agreement with the value obtained from mass spectrometry and has 2.3 times lower uncertainty. From combined MHI, H/D and muonic H/D data, we determine the baryon mass ratio md/mp with 1.1×1010 absolute uncertainty. The value agrees with the directly measured mass ratio6. Finally, we present a match between a theoretical prediction and an experimental result, with a fractional uncertainty of 8.1×1012. Both results indicate a notable confirmation of the predictive power of quantum theory and the absence of beyond-the-standard-model effects at these levels.

DOI: 10.1038/s41586-025-09306-2

Source: https://www.nature.com/articles/s41586-025-09306-2