Buras Andrzej J
TUM Institute for Advanced Study, Lichtenbergstr. 2a, 85747 Garching, Germany.
Physik Department, TU München, James-Franck-Straße, 85748 Garching, Germany.
Eur Phys J C Part Fields. 2023;83(1):66. doi: 10.1140/epjc/s10052-023-11222-6. Epub 2023 Jan 24.
The Standard Model (SM) does not contain by definition any new physics (NP) contributions to any observable but contains four CKM parameters which are not predicted by this model. We point out that if these four parameters are determined in a global fit which includes processes that are infected by NP and therefore by sources outside the SM, the resulting so-called SM contributions to rare decay branching ratios cannot be considered as SM contributions to the latter. On the other hand SM predictions, that are from the CKM dependence, can be obtained for suitable ratios of the and rare decay branching ratios to , and , all calculated within the SM. These three observables contain by now only small hadronic uncertainties and are already well measured so that rather precise SM predictions for the ratios in question can be obtained. In this context the of NP infection in the sector is provided by a plot that involves , , , and the mixing induced CP-asymmetry . As with the present hadronic matrix elements this test turns out to be , assuming negligible NP infection in the sector and setting the values of these four observables to the experimental ones, allows to obtain SM predictions for all and rare decay branching ratios that are most accurate to date and as a byproduct to obtain the full CKM matrix on the basis of transitions Using this strategy we obtain SM predictions for 26 branching ratios for rare semileptonic and leptonic and decays with the pair or the pair in the final state. Most interesting turn out to be the anomalies in the low bin in ( ) and ( ).
标准模型（SM）根据定义不包含对任何可观测量的任何新物理（NP）贡献，但包含四个CKM参数，而该模型并未预测这些参数。我们指出，如果在全局拟合中确定这四个参数，该全局拟合包括受NP影响因而受标准模型之外的源影响的过程，那么由此产生的对稀有衰变分支比的所谓标准模型贡献不能被视为标准模型对后者的贡献。另一方面，对于合适的(K^+\to\pi^+\nu\bar\nu)、(K_L\to\pi^0\nu\bar\nu)和(B\to K^\nu\bar\nu)衰变分支比与(K^+\to\pi^+\mu^+\mu^-)、(K_L\to\pi^0\mu^+\mu^-)和(B\to K^\mu^+\mu^-)的比率，可从CKM相关性获得标准模型预测，所有这些比率均在标准模型内计算。这三个可观测量目前仅包含较小的强子不确定性且已得到很好的测量，因此可以获得关于相关比率的相当精确的标准模型预测。在这种情况下，(K)介子领域中NP感染的程度由一个涉及(K^+\to\pi^+\nu\bar\nu)、(K_L\to\pi^0\nu\bar\nu)、(B\to K^\nu\bar\nu)以及混合诱导的CP不对称性(S_{\psi K_S})的(R)图给出。与当前的强子矩阵元一样，假设(B)介子领域中NP感染可忽略不计，并将这四个可观测量的值设为实验值，该检验结果表明，能够获得迄今最精确的所有(K)和(B)稀有衰变分支比的标准模型预测，并且作为副产品，基于(b\to s\nu\bar\nu)跃迁获得完整的CKM矩阵。使用此策略，我们获得了最终状态为(\mu^+\mu^-)对或(e^+e^-)对的26个稀有半轻子和轻子(K)和(B)衰变分支比的标准模型预测。最有趣的是在(K^+\to\pi^+\mu^+\mu^-)（(q^2)低区间）和(B\to K^\mu^+\mu^-)（(q^2)低区间）中的反常现象。
