Institut für Theoretische Teilchenphysik und Kosmologie, RWTH Aachen University, D-52056 Aachen, Germany and Institute for Theoretical Particle Physics, KIT, D-76128 Karlsruhe, Germany.
Institut für Theoretische Teilchenphysik und Kosmologie, RWTH Aachen University, D-52056 Aachen, Germany.
Phys Rev Lett. 2019 Aug 23;123(8):082001. doi: 10.1103/PhysRevLett.123.082001.
We calculate, for the first time, the next-to-next-to-leading order (NNLO) QCD corrections to spin correlations in top quark pair production at the LHC. The NNLO corrections play an important role in the description of the corresponding differential distributions. We observe that the standard model calculation describes the available Δϕ_{ℓℓ} data in the fiducial region but does not agree with the Δϕ_{ℓℓ} measurement extrapolated to full phase space. Most likely this discrepancy is due to the difference in precision between existing event generators and NNLO calculations for dilepton top-pair final states.
我们首次计算了 LHC 上顶夸克对产生中自旋关联的次领头阶（NNLO）QCD 修正。NNLO 修正在相应微分分布的描述中起着重要作用。我们观察到，标准模型计算在基准区域内描述了可用的Δϕ_{ℓℓ}数据，但与全相空间扩展的Δϕ_{ℓℓ}测量值不一致。这种差异很可能是由于现有的两体事例产生器与 NNLO 计算在双轻子顶夸克对末态的精度不同所致。
