No Arabic abstract
Lilith is a public Python library for constraining new physics from Higgs signal strength measurements. Version 2.0 of Lilith comes with an extensive XML database which includes the ATLAS and CMS Run 2 Higgs results for 36/fb, in addition the the Run 1 results. Both the code and the database were extended from the ordinary Gaussian approximation employed in Lilith-1.1 to using variable Gaussian and Poisson likelihoods. Moreover, Lilith-2 can make use of correlation matrices of arbitrary dimension. We will report on these novelties and ongoing developments. The importance of how correlations and uncertainties are treated will be demonstrated by means of detailed validations of the implemented experimental results. Moreover, we show the effects for global fits of reduced Higgs couplings, 2HDMs of Type I and Type II, and invisible Higgs decays. The program is publicly available on GitHub and can be used to constrain a wide class of new physics scenarios.
Lilith is a public Python library for constraining new physics from Higgs signal strength measurements. We here present version 2.0 of Lilith together with an updated XML database which includes the current ATLAS and CMS Run 2 Higgs results for 36/fb. Both the code and the database were extended from the ordinary Gaussian approximation employed in Lilith-1.1 to using variable Gaussian and Poisson likelihoods. Moreover, Lilith can now make use of correlation matrices of arbitrary dimension. We provide detailed validations of the implemented experimental results as well as a status of global fits for reduced Higgs couplings, Two-Higgs-doublet models of Type I and Type II, and invisible Higgs decays. Lilith-2.0 is available on GitHub and ready to be used to constrain a wide class of new physics scenarios.
The properties of the observed Higgs boson with mass around 125 GeV can be affected in a variety of ways by new physics beyond the Standard Model (SM). The wealth of experimental results, targeting the different combinations for the production and decay of a Higgs boson, makes it a non-trivial task to assess the compatibility of a non-SM-like Higgs boson with all available results. In this paper we present Lilith, a new public tool for constraining new physics from signal strength measurements performed at the LHC and the Tevatron. Lilith is a Python library that can also be used in C and C++/ROOT programs. The Higgs likelihood is based on experimental results stored in an easily extensible XML database, and is evaluated from the user input, given in XML format in terms of reduced couplings or signal strengths. The results of Lilith can be used to constrain a wide class of new physics scenarios.
The properties of the observed Higgs boson with mass around 125 GeV are constrained by a wealth of experimental results targeting different combinations for the production and decay of a Higgs boson. In order to assess the compatibility of a non-Standard Model-like Higgs boson with all available results, we present Lilith, a new public tool that makes use of signal strength measurements performed at the LHC and the Tevatron.
After the discovery of a scalar resonance, resembling the Higgs boson, its couplings have been extensively studied via the measurement of various production and decay channels on the invariant mass peak. Recently, it has been suggested the possibility to use off-shell measurements: in particular, CMS has published results based on the high- invariant mass cross section of the process $gg to ZZ$, which contains the contribution of the Higgs. While this measurement has been interpreted as a constraint on the Higgs width after very specific assumptions are taken on the Higgs couplings, in this letter we show that a much more model-independent interpretation is possible.
The program HiggsSignals confronts the predictions of models with arbitrary Higgs sectors with the available Higgs signal rate and mass measurements, resulting in a likelihood estimate. A new version of the program, HiggsSignals-2, is presented that contains various improvements in its functionality and applicability. In particular, the new features comprise improvements in the theoretical input framework and the handling of possible complexities of beyond-the-SM Higgs sectors, as well as the incorporation of experimental results in the form of Simplified Template Cross Section (STXS) measurements. The new functionalities are explained, and a thorough discussion of the possible statistical interpretations of the HiggsSignals results is provided. The performance of HiggsSignals is illustrated for some example analyses. In this context the importance of public information on certain experimental details like efficiencies and uncertainty correlations is pointed out. HiggsSignals is continuously updated to the latest experimental results and can be obtained at https://www.gitlab.com/higgsbounds/higgssignals .