HiggsBounds-5: testing Higgs sectors in the LHC 13 TeV Era

We describe recent developments of the public computer code . In particular, these include the incorporation of LHC Higgs search results from Run 2 at a center-of-mass energy of 13 TeV, and an updated and extended framework for the theoretical input that accounts for improved Higgs cross section and branching ratio predictions and new search channels. We furthermore discuss an improved method used in to approximately reconstruct the exclusion likelihood for LHC searches for non-standard Higgs bosons decaying to $$\tau \tau $$ τ τ final states. We describe in detail the new and updated functionalities of the new version .

Invisible Higgs search through vector boson fusion: a deep learning approach

Vector boson fusion proposed initially as an alternative channel for finding heavy Higgs has now established itself as a crucial search scheme to probe different properties of the Higgs boson or for new physics. We explore the merit of deep-learning entirely from the low-level calorimeter data in the search for invisibly decaying Higgs. Such an effort supersedes decades-old faith in the remarkable event kinematics and radiation pattern as a signature to the absence of any color exchange between incoming partons in the vector boson fusion mechanism. We investigate among different neural network architectures, considering both low-level and high-level input variables as a detailed comparative analysis. To have a consistent comparison with existing techniques, we closely follow a recent experimental study of CMS search on invisible Higgs with 36 fb$$^{-1}$$ - 1 data. We find that sophisticated deep-learning techniques have the impressive capability to improve the bound on invisible branching ratio by a factor of three, utilizing the same amount of data. Without relying on any exclusive event reconstruction, this novel technique can provide the most stringent bounds on the invisible branching ratio of the SM-like Higgs boson. Such an outcome has the ability to constraint many different BSM models severely.

New physics implication of Higgs precision measurements

Studying the properties of the Higgs boson can be an important window to explore the physics beyond the Standard Model (SM). In this work, we present studies on the implications of the Higgs precision measurements at future Higgs Factories. We perform a global fit to various Higgs search channels to obtain the 95% C.L. constraints on the model parameter spaces of two-Higgs Doublet Model (2HDM) and Minimal Supersymmetric Standard Model (MSSM). In the 2HDM, we analyze tree-level effects as well as one-loop contributions from the heavy Higgs bosons. The strong constraints on [Formula: see text], heavy Higgs masses and their mass splitting are complementary to direct search of the LHC as well as possible future [Formula: see text] pole precision measurements. For the MSSM, we study both the Higgs couplings and mass precisions. The constraints on the CP-odd Higgs mass [Formula: see text] and stop mass scale [Formula: see text] can be complementary to the direct search of HL-LHC. We also compare the sensitivity of various future Higgs factories, namely, Circular Electron Positron Collider (CEPC), Future Circular Collider (FCC)-ee and International Linear Collider (ILC).

Gauge-Singlet Vector-Like Fermion Dark Matter, LHC Diphoton Rate, and Direct Detection

We study a gauge-singlet vector-like fermion hidden sector dark matter model, in which the communication between the dark matter and the visible standard model sector is via the Higgs-portal scalar-Higgs mixing and also via a hidden sector scalar with loop-level couplings to two gluons and also to two hypercharge gauge bosons induced by a vector-like quark. We find that the Higgs-portal possibility is stringently constrained to be small by the recent LHC di-Higgs search limits, and the loop induced couplings are important to include. In the model parameter space, we present the dark matter relic density, the dark-matter-nucleon direct detection scattering cross section, the LHC diphoton rate from gluon-gluon fusion, and the theoretical upper bounds on the fermion-scalar couplings from perturbative unitarity.

Production and decay of radion in Randall–Sundrum model at a photon collider

A warped extra dimension model predicts an extra scalar particle beyond the Standard Model (SM) which is called a radion. Although interactions of the radion are similar to those of the Higgs boson in the SM, a relatively light radion (≲100 GeV) is not severely constrained from the Higgs search experiments at the LHC. In this paper we study discovery potential of the radion at a photon collider as an option of ILC. Owing to the trace anomaly of the energy–momentum tensor, both a production of radion in γγ collision and its decay to gluon pair are enhanced sizably. We find that the photon collider has a sensitivity for discovering the radion in low-mass region up to Λϕ~3 TeV, where Λϕ is a scale parameter which suppresses the interactions of radion to the SM particles.

Interplay of flavor and collider physics

We present an overview on the interplay between direct searches for new physics at the LHC and indirect constraints from flavor physics, with an emphasis on the implications of the recent LHCb results. The complementarity with the Higgs search results will also be addressed. We show the correlations and complementarity between the different sectors in the context of a few specific scenarios in supersymmetry.