近日，国际CMS协作组报道了用CMS实验高精度测量W玻色子质量。相关论文于2026年4月8日发表在《自然》杂志上。

在粒子物理标准模型中，弱相互作用载体W和Z玻色子的质量之间存在唯一确定的关系。精确测定它们的质量至关重要，因为未知重粒子的量子圈图可能会改变这一关系。尽管Z玻色子的质量已被测定到百万分之22（2.0 MeV）的惊人精度，但W玻色子质量的测定精度要低得多。对电弱可观测量的整体拟合预测W玻色子质量的不确定度为6 MeV。要达到相当的实验精度，将是对标准模型的一项敏感且根本性的检验，而费米实验室Tevatron对撞机上CDF合作组最近的测量结果对整体拟合预测提出了挑战，这使得此项工作更加紧迫。

研究组报告了CMS协作组在CERN大型强子对撞机上基于2016年在质子-质子对撞能量13 TeV下收集的大样本W → μν事件，对W玻色子质量的测量结果。该测量利用高粒度最大似然拟合，分析了W衰变中产生的μ子的运动学性质。通过将实验效应的精确确定与理论输入显著的原位约束相结合，研究组达到了对W玻色子质量的精确测量，结果为80,360.2 ± 9.9 MeV，与标准模型预测一致。

附：英文原文

Title: High-precision measurement of the W boson mass with the CMS experiment

Author: anonymous

Issue&Volume: 2026-04-08

Abstract: In the standard model of particle physics, the masses of the W and Z bosons, the carriers of the weak interaction, are uniquely related. A precise determination of their masses is important because quantum loops of heavy, undiscovered particles could modify this relationship. Although the Z mass is known to the remarkable precision of 22parts per million (2.0MeV), the W mass is known much less precisely. A global fit to measured electroweak observables predicts the W mass with 6MeV uncertainty1,2,3. Reaching a comparable experimental precision would be a sensitive and fundamental test of the standard model, made even more urgent by a recent challenge to the global fit prediction by a measurement from the CDF Collaboration at the Fermilab Tevatron collider4. Here we report the measurement of the W mass by the CMS Collaboration at the CERN Large Hadron Collider, based on a large data sample of W → μν events collected in 2016 at the proton–proton collision energy of 13TeV. The measurement exploits a high-granularity maximum likelihood fit to the kinematic properties of muons produced in W decays. By combining an accurate determination of experimental effects with marked in situ constraints of theoretical inputs, we reach a precise measurement of the W mass, of 80,360.2 ± 9.9MeV, in agreement with the standard model prediction.

DOI: 10.1038/s41586-026-10168-5

Source: https://www.nature.com/articles/s41586-026-10168-5