Dipartimento di Fisica, Sapienza-Università di Roma, Piazzale Aldo Moro 5, 00185, Rome, Italy.
INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185, Rome, Italy.
Phys Rev Lett. 2018 Oct 19;121(16):162003. doi: 10.1103/PhysRevLett.121.162003.
We propose a new method to calculate analytically higher-order perturbative corrections and we apply it to the calculation of the two-loop virtual corrections to Higgs pair production through gluon fusion. The method is based on the expansion of the amplitudes in terms of a small Higgs transverse momentum. This approach gives a very good approximation (better than per mille) of the partonic cross section in the center-of-mass energy region sqrt[s[over ^]]≲750 GeV, where ∼95% of the total hadronic cross section is concentrated. The presented method is general and can be applied in a straightforward way to the computation of virtual higher-order corrections to other 2→2 processes, representing an improvement with respect to calculations based on heavy mass expansions.
我们提出了一种新的方法来解析地计算高阶微扰修正，并将其应用于通过 gluong 融合产生 Higgs 对的双圈虚修正的计算。该方法基于振幅在小 Higgs 横向动量下的展开。这种方法在质心能量区域 sqrt[s[over ^]]≲750 GeV 下给出了非常好的（优于千分之一）部分子横截面积的近似值，其中总强子横截面积的 ∼95%集中在此处。所提出的方法是通用的，可以直接应用于其他 2→2 过程的虚高阶修正的计算，与基于重质量展开的计算相比有所改进。
