ewN2HDECAY—A program for the calculation of Electroweak one-loop corrections to Higgs decays in the Next-to-Minimal Two-Higgs-Doublet Model including state-of-the-art QCD corrections

We present in this paper our new program package ewN2HDECAY for the calculation of the partial decay widths and branching ratios of the Higgs bosons of the Next-to-Minimal 2-Higgs Doublet Model (N2HDM). The N2HDM is based on a general CP-conserving 2HDM which is extended by a real scalar singlet field. The program computes the complete electroweak one-loop corrections to all non-loop-induced two-body on-shell Higgs boson decays in the N2HDM and combines them with the state-of-the-art QCD corrections that are already implemented in the existing program N2HDECAY. Most of the independent input parameters of the electroweak sector of the N2HDM are renormalized in an on-shell scheme. The soft-Z_2-breaking squared mass scale m^2_{12} and the vacuum expectation value v_S of the SU(2)_L singlet field, however, are renormalized with MS conditions, while for the four scalar mixing angles α_i (i=1, 2, 3) and β of the N2HDM, several different renormalization schemes are applied. By giving out the leading-order and the loop-corrected partial decay widths separately from the branching ratios, the program ewN2HDECAY not only allows for phenomenological analyses of the N2HDM at highest precision, it can also be used for a study of the impact of the electroweak corrections and the remaining theoretical uncertainty due to missing higher-order corrections based on a change of the renormalization scheme. The input parameters are then consistently calculated with a parameter conversion routine when switching from one renormalization scheme to the other. The latest version of the program ewN2HDECAY can be downloaded from the URL https://github.com/marcel-krause/ewN2HDECAY.

本文介绍了一款全新的程序包ewN2HDECAY，用于计算次最小双希格斯二重态模型（Next-to-Minimal 2-Higgs Doublet Model, N2HDM）中希格斯玻色子的部分衰变宽度与分支比。N2HDM基于一般CP守恒的双希格斯二重态模型，通过引入实标量单态场进行扩展。该程序可针对N2HDM中所有非圈诱导的双体在壳希格斯玻色子衰变，计算完整的电弱单圈修正，并将其与现有程序N2HDECAY中已集成的当前最先进的量子色动力学（QCD）修正相结合。N2HDM电弱扇区的多数独立输入参数采用在壳（on-shell）方案进行重整化，但软Z₂破缺平方质量标度$m^2_{12}$与SU(2)_L单态场的真空期望值$v_S$则采用最小减除（MS）方案进行重整化；而针对N2HDM的四个标量混合角$alpha_i$（$i=1,2,3$）与$eta$，则采用了多种不同的重整化方案。程序ewN2HDECAY可分别输出领头阶与圈修正后的部分衰变宽度，以及分支比，这使其不仅能够以最高精度开展N2HDM的唯象分析，还可用于研究电弱修正的影响，以及基于重整化方案变化所带来的、源于遗漏高阶修正的剩余理论不确定性。当从一种重整化方案切换至另一种时，程序将通过参数转换程序对输入参数进行一致性计算。该程序ewN2HDECAY的最新版本可从以下网址下载：https://github.com/marcel-krause/ewN2HDECAY。