h\to γγIn Inert Higgs Doublet Model (1201.2644v2)

Abstract: Motivated by the recent result reported from LHC on the di-photon search for a Standard Model (SM) Higgs-like boson. We discuss the implications of this possible signal in the framework of the Inert Higgs Doublet Model (IHDM), taking into account previous limits from Higgs searches at LEP, the Tevatron and the LHC as well as constraints from unitarity, vacuum stability and electroweak precision tests. We show that the charged Higgs contributions can interfere constructively or destructively with the W gauge bosons loops leading to enhancement or suppression of the di-photon rate with respect to SM rate. We show also that the invisible decay of the Higgs, if open, could affect the total width of the SM Higgs boson and therefore suppress the di-photon rate.

• The paper demonstrates that charged Higgs interference can enhance or suppress the γγ decay rate relative to Standard Model predictions.
• It employs a detailed parameter scan using unitarity, vacuum stability, and electroweak constraints to identify viable IHDM scenarios.
• The results inform future LHC searches and dark matter studies by refining constraints on charged Higgs masses and coupling strengths.

Overview: Higgs Boson in the Inert Higgs Doublet Model

The paper "Higgs to gamma gamma in Inert Higgs Doublet Model" presents an examination of a possible signal in the di-photon ($\gamma\gamma$) decay channel of a Higgs-like boson within the framework of the Inert Higgs Doublet Model (IHDM). The paper is motivated by recent results from the Large Hadron Collider (LHC) regarding searches for the Standard Model (SM) Higgs boson. The paper assesses the impact of this discovery within IHDM, relying on existing constraints from particle physics experiments and fundamental physics principles such as unitarity, vacuum stability, and precision electroweak tests.

Context and Background

The discovery of the Higgs boson is central to understanding electroweak symmetry breaking (EWSB) in particle physics. Beyond the Standard Model (BSM), various theories, including the Inert Higgs Doublet Model, propose extensions to account for phenomena such as dark matter (DM). IHDM posits two Higgs doublets, one of which is 'inert' and does not acquire a vacuum expectation value (vev) or interact with fermions. This extension facilitates a decoupled DM candidate, providing intriguing phenomenological implications, especially regarding Higgs boson decay modes such as $h \to \gamma\gamma$.

Contributions and Numerical Analysis

The paper focuses particularly on the $\gamma\gamma$ mode, wherein charged Higgs contributions can lead to enhancement or suppression of the di-photon rate relative to the SM. The analysis highlights scenarios where charged Higgs interference either amplifies or diminishes the rate when contrasted with W boson loop contributions. Additionally, the IHDM allows for the Higgs to decay invisibly into DM particles, significantly altering the Higgs' total decay width and affecting the observable di-photon signals.

Both theoretical and experimental constraints are meticulously reviewed, facilitating a parameter space scan to gauge potential deviations from SM predictions. The authors systematically demonstrate how under certain conditions (e.g., charged Higgs masses, coupling strengths), the IHDM can reproduce or diverge from the di-photon excess reported by LHC ATLAS and CMS collaborations.

Implications and Future Work

The implications of these findings extend to constraining IHDM parameters via LHC Higgs searches. Notably, confirming enhancement in the $\gamma\gamma$ channel could suggest a relatively light charged Higgs and particular coupling dynamics. Conversely, suppression would implicate open invisible decay modes. The interplay of these factors has substantial implications for DM phenomenology and Higgs searches.

Additionally, these results inspire further studies and potential collider experiments aiming to validate IHDM's viability against SM predictions. The authors stress the role of future high-luminosity data in resolving these observations, potentially refining or redefining constraints on the model parameters.

Conclusion

In summation, through detailed numerical analysis, the paper sheds light on the versatility of the IHDM in interpreting current Higgs boson search results. It underscores the necessity of rigorous examination of BSM scenarios like IHDM in the context of LHC data, considering both their theoretical underpinning and potential experimental validation. The paper constitutes a significant contribution to ongoing efforts to discern the nuances in Higgs boson physics and their broader cosmological implications.