Applying Exclusion Likelihoods from LHC Searches to Extended Higgs Sectors

Abstract: LHC searches for non-standard Higgs bosons decaying into tau lepton pairs constitute a sensitive experimental probe for physics beyond the Standard Model (BSM), such as Supersymmetry (SUSY). Recently, the limits obtained from these searches have been presented by the CMS collaboration in a nearly model-independent fashion - as a narrow resonance model - based on the full 8 TeV dataset. In addition to publishing a 95% C.L. exclusion limit, the full likelihood information for the narrow resonance model has been released. This provides valuable information that can be incorporated into global BSM fits. We present a simple algorithm that maps an arbitrary model with multiple neutral Higgs bosons onto the narrow resonance model and derives the corresponding value for the exclusion likelihood from the CMS search. This procedure has been implemented into the public computer code HiggsBounds (version 4.2.0 and higher). We validate our implementation by cross-checking against the official CMS exclusion contours in three Higgs benchmark scenarios in the Minimal Supersymmetric Standard Model (MSSM), and find very good agreement. Going beyond validation, we discuss the combined constraints of the tau tau search and the rate measurements of the SM-like Higgs at 125 GeV in a recently proposed MSSM benchmark scenario, where the lightest Higgs boson obtains SM-like couplings independently of the decoupling of the heavier Higgs states. Technical details for how to access the likelihood information within HiggsBounds are given in the appendix. The program is available at http://higgsbounds.hepforge.org.

• The paper introduces a computational framework to apply CMS exclusion likelihoods to extended Higgs sectors in models beyond the Standard Model.
• It validates the method against MSSM benchmarks like mₕᵐₐₓ and low-M_H scenarios, demonstrating strong agreement with experimental contours.
• The approach enhances parameter space constraints and guides future experimental designs by incorporating detailed LHC likelihood profiles.

Assessing Exclusion Likelihoods from LHC Searches in Extended Higgs Sectors

The research paper titled "Applying Exclusion Likelihoods from LHC Searches to Extended Higgs Sectors" investigates an advanced methodology to apply exclusion likelihoods from Large Hadron Collider (LHC) searches to examine extended Higgs sectors. This inquiry mainly targets models that propose physics beyond the Standard Model, such as Supersymmetry (SUSY), with a focus on constraining parameter spaces using non-standard Higgs boson searches.

Broadly, the analysis hinges on data from the CMS collaboration, which released likelihood information based on narrow resonance models derived from their extensive $8$TeV dataset. This paper introduces a computational approach integrated within the public code Higgs, which maps any model with neutrally-charged Higgs bosons onto the specific narrow resonance framework of the CMS results. A critical achievement here is the assessment of exclusion likelihood, allowing researchers to incorporate detailed likelihood profiles into global fits of BSM theories.

Validation and Application

Validation is performed by comparing generated exclusion contours against those released by CMS for various Minimum Supersymmetric Standard Model (MSSM) scenarios. The study reports very good agreement for cases like the $m_h^\text{max}$, light stop, and low-$M_H$ scenarios, although slight conservatism is noted in regions with overlapping contributions from multiple Higgs bosons.

Applying the likelihood analysis, the team explores the constraints on an MSSM benchmark scenario branded as "alignment without decoupling." Here, the focus is on configurations where the lightest Higgs boson adopts SM-like characteristics without necessitating the decoupling of heavier states.

Practical Implications

From a practical standpoint, the improved ability to gauge exclusion likelihoods enhances our capacity to delineate the parameter spaces of diverse models, effectively steering experimental prioritizations and interpretations. The implication extends to influencing the design of future experiments, with the criterion for exclusion based on comprehensive exclusion likelihoods being more robust than binary acceptance criteria.

Theoretical Implications and Future Directions

Theoretically, the research contributes a linchpin methodology to rigorous model evaluation by successfully transitioning beyond isolated exclusion limits to holistic likelihood characterizations. This methodology lays a foundation for future theoretical efforts aimed at examining scenarios with complex scalar sectors, such as those encountered in Two-Higgs-Doublet Models.

In terms of ongoing and future work, the authors encourage continued release of likelihood data from the LHC experiments, which will vastly improve the utility of such analyses. Further developments might also explore enhancements incorporating interference effects of resonant signals and evaluate their impact on exclusion regions.

In summary, the methodology detailed in this paper represents a significant step in refining the theoretical toolkit for LHC data interpretation by providing a powerful framework to apply rigorous statistical analysis to non-standard Higgs boson searches. This synergistic approach marries experimental data with theoretical models, facilitating more precise constraints on BSM physics and aligning computational predictions with empirical findings.