$\texttt{history}$ in the making: A tool for NNLO cross sections

TL;DR

history introduces a framework that implements the fully-local Nested Soft-Collinear (NSC) subtraction to automate NNLO QCD predictions for color-singlet production in hadronic collisions. Validation against the established vh@nnlo results for $pp \to ZH+X$ at $\sqrt{s}=13$ TeV shows agreement in both total cross sections and differential spectra, confirming correct IR cancellation and precise phase-space integration. The first phenomenological application analyzes associated $ZH$ production including the loop-induced gluon-fusion channel and defines the $R^{VH}$ double ratio to separate gluon- from DY contributions while probing BSM effects through variations in the top Yukawa coupling, with pronounced sensitivity in $M_{ZH}$ and $y_H$ distributions. The framework is set for extension to additional color-singlet processes and BSM scenarios, with ongoing work on gluon-initiated NNLO terms and broader observables.

Abstract

In these proceedings, we report on our progress in developing the $\texttt{history}$ framework, which aims to implement the fully-local Nested Soft-Collinear infrared subtraction scheme for the automated phase-space integration of color-singlet production processes in hadronic collisions at NNLO accuracy. We validate our implementation for quark-antiquark-initiated processes and demonstrate a first application of the tool by predicting a novel observable for the inclusive process $pp \to ZH+X$, which may offer sensitivity to potential effects of new physics.

Figures (3)

• Figure 1: Feynman diagrams for associated Higgs production. Panel (a) shows the Drell-Yan mechanism, initiated by quark-antiquark annihilation with an intermediate vector boson $V$, where $V$ denotes either a $W$ or a $Z$ boson. Panels (b) and (c) depict the loop-induced gluon-fusion contributions to $ZH$ production. The diagrams are generated with FeynGamefeyngamefeyngame2feyngame3.
• Figure 2: left: Total inclusive NNLO cross section for $pp \to ZH+X$ via the Drell-Yan mechanism and the contributions from the individual partonic channels compared between history (upper values) and vh@nnlo (lower values). Statistical Monte Carlo uncertainties on the last two digits are quoted in parentheses. right: Invariant mass spectrum for $pp \to ZH+X$ at NNLO precision. The upper panel shows the spectra computed with history (blue) and vh@nnlo (green). The lower panel displays their ratios normalized to the vh@nnlo distribution. The shaded bands indicate the statistical Monte Carlo uncertainties.
• Figure 3: The $R^{VH}$ double ratio as function of (a) the invariant mass $M_{ZH}$ obtained with vh@nnlo, a reproduced plot from ref. Harlander:2018yns, and (b) the rapidity of the Higgs boson $y_H$ obtained with history. The double ratios are computed in the SM (blue), the SM without a top-to-Higgs Yukawa coupling (green), and the SM with a doubled top-to-Higgs Yukawa coupling (red).