We propose a novel test to assess the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, VCKM, at present and future collider experiments. Our strategy makes use of the W+W− production cross section to directly probe the VCKM†VCKM product, which regulates the high-energy behavior of the observable. The violation of unitarity is signaled by an anomalous behavior of the cross section that grows quadratically with the W+W− invariant mass with respect to the Standard Model prediction. By using the recent ATLAS measurements of the W+W− cross section we are able to constrain the maximal unitarity violation allowed by current data, producing a bound complementary to the results of flavor physics experiments. Forecasts for the high luminosity phase of the LHC and for the future 100 TeV hadron collider are also discussed.

中文翻译：

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通过在 LHC 和未来的对撞机上产生 W+W− 来测试高能量下的 CKM 幺正性


我们提出了一种新的测试来评估 Cabibbo-Kobayashi-Maskawa 矩阵 VCKM 在当前和未来对撞机实验中的幺正性。我们的策略利用 W+W− 产生截面直接探测 VCKM†VCKM 积，它调节可观察对象的高能量行为。违反幺正性是由横截面的异常行为发出信号的，该异常行为相对于标准模型预测，该异常行为随 W+W− 不变质量的二次方增长。通过使用最近对 W+W− 横截面的 ATLAS 测量，我们能够约束当前数据允许的最大幺正性违规，从而产生与风味物理学实验结果的有界互补。还讨论了对 LHC 高光度阶段和未来 100 TeV 强子对撞机的预测。