Bern Zvi, Kosower David, Parra-Martinez Julio
Mani L. Bhaumik Institute for Theoretical Physics, UCLA Department of Physics and Astronomy, Los Angeles, CA 90095, USA.
Institut de Physique Théorique, CEA, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette cedex, France.
Proc Math Phys Eng Sci. 2020 Mar;476(2235):20190722. doi: 10.1098/rspa.2019.0722. Epub 2020 Mar 25.
We compute the anomalous two-loop four-point amplitudes in pure supergravity, using unitarity and the double-copy construction. We also present all terms determined by four-dimensional cuts in two all-multiplicity two-loop anomalous superamplitudes. This result provides the first two-loop -point gravity amplitude, up to a class of undetermined terms, which we determine completely at four points. We show that a recently proposed finite counterterm cancels these amplitudes to this order. We argue that the counterterm does not spoil the three-loop finiteness of anomalous amplitudes in the theory.
我们利用幺正性和双拷贝构造计算了纯超引力中反常的两圈四点振幅。我们还给出了在两个全多重性两圈反常超振幅中由四维切割确定的所有项。该结果给出了首项两圈四点引力振幅，直至一类未确定项，我们在四点处完全确定了这些项。我们表明，最近提出的有限抵消项将这些振幅抵消到该阶次。我们认为该抵消项不会破坏该理论中反常振幅的三圈有限性。
