SusHi Bento: Beyond NNLO and the heavy-top limit (1605.03190v2)

Abstract: Version 1.6.0 of the code SusHi is presented. Concerning inclusive CP-even Higgs production in gluon fusion, the following new features with respect to previous versions have been implemented: expansion of the partonic cross section in the soft limit, i.e. around $x=M_H^2/\hat{s}\to 1$; N$^3$LO QCD corrections in terms of the soft expansion; top-quark mass suppressed terms through NNLO; matching to the cross section at $x\to 0$ through N$^3$LO. For CP-even and -odd scalars, an efficient evaluation of the renormalization-scale dependence is included, and effects of dimension-5 operators can be studied, which we demonstrate for the SM Higgs boson and for a CP-even scalar with a mass of $750$ GeV. In addition, as a generalization of the previously available $b\bar{b}\to H$ cross section, SusHi 1.6.0 provides the cross section for charged and neutral Higgs production in the annihilation of arbitrary heavy quarks. At fixed order in perturbation theory, SusHi thus allows to obtain Higgs cross-section predictions in different models to the highest precision known today. For the SM Higgs boson of $M_H=125$ GeV, SusHi yields $48.28$ pb for the gluon-fusion cross section at the LHC at $13$ TeV. Simultaneously, SusHi provides the renormalization-scale uncertainty of $\pm 1.97$ pb.

• The paper presents N3LO corrections via soft expansion at threshold, significantly enhancing precision in gluon fusion Higgs production calculations.
• It employs inverse power expansions for top-quark mass effects and extends predictions across models like 2HDM, MSSM, and NMSSM.
• The study demonstrates numerical precision with a computed 48.28 pb cross section and ±1.97 pb uncertainty for a 125 GeV Higgs at 13 TeV.

An Analytical Examination of the SusHi Bento Program for Higgs Production

The paper "SusHi Bento: Beyond NNLO and the heavy-top limit," authored by Robert V. Harlander, Stefan Liebler, and Hendrik Mantler, presents advancements in computational predictions concerning Higgs boson production in gluon fusion processes. The SusHi Bento program, elaborated upon in this paper, represents version 1.6.0, offering notable developments beyond previous iterations, particularly through the inclusion of higher-order perturbative calculations in particle physics. This paper is designed for theoretical particle physicists looking to incorporate comprehensive and high-precision cross-section calculations in their research, particularly those investigating Higgs bosons within various Standard Model extensions.

Program Features and Novel Implementations

The primary enhancement introduced by SusHi Bento is the inclusion of next-to-next-to-next-to-leading order (N3LO) corrections in the heavy-top quark limit. These corrections are facilitated through a soft expansion methodology at the partonic level, utilizing the variable $x=H^2/\hat{s}$, allowing precise calculations near the production threshold ($x \to 1$). The integration of these corrections epitomizes a significant leap in computational accuracy. Furthermore, top-quark mass effects are treated through expansions in inverse powers of the mass, enabling detailed examination of their contributions to gluon-fusion processes.

The program extends its capabilities by providing predictions for scalar production across a spectrum of models, including the Standard Model, the Two-Higgs-Doublet Model (2HDM), and both the Minimal (MSSM) and next-to-minimal (NMSSM) Supersymmetric Standard Models. Particularly, SusHi Bento can now evaluate Higgs production through the annihilation of arbitrary heavy quarks. The inclusion of dimension-5 operator effects further augments the program's versatility in analyzing Higgs sectors.

Numerical Precision and Scale Dependencies

The paper details numerical results illustrating the predictive strength of SusHi Bento. For a Higgs mass of 125 GeV, the gluon-fusion cross section at a hadron collider operating at a center-of-mass energy (CME) of 13 TeV is computed to be 48.28 picobarns (pb), accentuating the model’s precision. The authors confirm the renormalization-scale uncertainty to be approximately ±1.97 pb, exemplifying the program’s adeptness in uncertainty calibration. This precision enables researchers to explore beyond-Standard Model contributions without being hindered by computational inaccuracies.

Additionally, the program integrates a sophisticated mechanism of scale dependence analysis via a “RGE procedure”—a methodology that expedites the evaluation of renormalization scale factors. This feature promotes efficient parameter scans across various scales, aiding both practical and theoretical analyses.

Implications and Future Developments

SusHi Bento’s extensions into N3LO predictions and soft limit expansions profoundly impact our understanding and simulation capabilities of Higgs production processes. The paper emphasizes the theoretical implications of integrating dimension-5 operators, presenting opportunities for probing new physics beyond current model predictions. Importantly, this program paves the way for more precise Higgs searches and could influence ongoing experimental setups at particle colliders.

In conclusion, SusHi Bento serves as a pivotal tool for researchers immersed in the exploration of Higgs physics. It marks a pivotal advancement in theoretical predictions, aligning computational results closely with experimental data. Continued development of such software is imperative to further unveil the complexities within Higgs boson interactions, possibly shedding light on new physical paradigms. As computational demands rise with experimental precision, tools like SusHi Bento will remain indispensable in theoretical particle physics, supporting future discoveries and extending current boundaries.