The search for di-Higgs final states is typically limited at the LHC to the dominant gluon fusion channels, with weak boson fusion only assuming a spectator role. In this work, we demonstrate that when it comes to searches for resonant structures that arise from iso-singlet mixing in the Higgs sector, the weak boson fusion sideline can indeed contribute to winning the discovery game. Extending existing experimental resonance searches by including both contributions is therefore crucial.
We present some of the most recent results from the CMS Collaboration on searches for Higgs-like particles in models beyond the Standard Model. Several rare and exotic decay modes of the Higgs boson are explored. The results of the searches are relevant for establishing whether the 125 GeV particle observed in Higgs boson searches at the LHC has the properties expected for a Standard Model Higgs boson.
Recent results of searches for Higgs bosons by the CMS collaboration are presented. These consist of searches for rare Higgs boson decays, searches for additional neutral Higgs bosons, and searches for charged Higgs bosons.
The present status of ATLAS searches for Higgs bosons in extensions of the Standard Model (SM) is presented. This includes searches for the Higgs bosons of the Two-Higgs-Doublet Model (2HDM), the Minimal Supersymmetric Model (MSSM), the Next-to-Minimal Supersymmetric Model (NMSSM) and models with an invisibly decaying Higgs boson. A review of the phenomenology of the Higgs sectors of these models is given together with the search strategy and the resulting experimental constraints.
A review of the current experimental results on searches for Higgs bosons in models beyond the Standard Model is presented. Searches from ATLAS, CMS and LHCb use datasets from Run 1 of the LHC, including 7 and 8 TeV proton-proton collisions. Searches from CDF and D0 use the full or partial 1.96 TeV proton-anti-proton collision datasets from the Tevatron.
Since the discovery of the Higgs boson in the year 2012, the CMS experiment continuously makes use of a variety of final states to measure the properties of the Higgs boson, as well as to search for it in final states where the discovery could not yet be established. This article concentrates on Higgs searches in fermionic final states including a search for the Standard Model Higgs boson in the $H \rightarrow b\overline{b}$ channel. Furthermore, three different searches for Higgs bosons beyond the Standard Model are presented. These comprise two searches for heavy neutral Higgs bosons and one…
An overview of the recent searches for Higgs boson pair production at the LHC was presented. The searches were based on approximately 140 $\mathrm{fb}^{-1}$ of data collected by the ATLAS and CMS experiments in proton-proton collisions at $\sqrt{s}$ = 13 TeV. With respect to the previous searches, analysis techniques were significantly improved, and new signatures and decays channels were explored.
Several new-physics (NP) models predict the existence of low-mass Higgs states and light dark matter candidates. Previous BABAR searches have given null results for these new states and have excluded large regions of the NP models parameter space. We report on new searches on light Higgs and light dark matter at BABAR using the 516 1/fb of data collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory.
There has been a tremendous increase of sensitivity in searches for charged Higgs bosons and additional neutral Higgs bosons since the last CHARGED workshop in 2016. We will review recent experimental and theory developments as presented at CHARGED2018, and conclude with future prospects for the field.
We study direct searches of additional Higgs bosons in multi-top-quarks events at the LHC Run-II, its luminosity upgraded version with 3000 fb$^{-1}$, and the International Linear Collider (ILC) with the collision energy of 1 TeV. Additional Higgs bosons are predicted in all kinds of extended Higgs sectors, and their detection at collider experiments is a clear signature of the physics beyond the standard model. We consider two Higgs doublet models with the discrete symmetry as benchmark models. If these additional Higgs bosons are heavy enough, the decay modes including top quarks can be domi…
While the existence of a Higgs boson with a mass near 125 GeV has been clearly established, the detailed structure of the entire Higgs sector is yet unclear. Besides the Standard Model interpretation, various possibilities for extended Higgs sectors are being considered. The minimal supersymmetric extension (MSSM) features two Higgs doublets resulting in five physical Higgs bosons, which are subject to direct searches. Alternatively, more generic Two-Higgs Doublet models (2HDM) are used for the interpretation of results. The Next-to-Minimal Supersymmetric Model (NMSSM) has a more complex Higgs…
We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searc…
We present an investigation of the dependence of searches for boosted Higgs bosons using jet substructure on the perturbative and non-perturbative parameters of the Herwig++ Monte Carlo event generator. Values are presented for a new tune of the parameters of the event generator, together with the an estimate of the uncertainties based on varying the parameters around the best-fit values.
The Monte Carlo integrator HAWK provides precision predictions for Higgs production at hadron colliders in vector-boson fusion and Higgs strahlung, i.e. in production processes where the Higgs boson is Attached to WeaK bosons. The fully differential predictions include the full QCD and electroweak next-to-leading-order corrections. Results are computed as integrated cross sections and as binned distributions for important hadron-collider observables.
Searches for Beyond the Standard Model Higgs processes in the context of Minimal Supersymmetric Standard Model and Next to MSSM are presented. The results are based on the first LHC run of pp collision data recorded by the ATLAS and CMS experiments at the CERN Large Hadron Collider at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of about 5 and 20 fb$^{-1}$ respectively. Current searches constrain large parts of the parameter space. No evidence for BSM Higgs is found.
The discovery of the Higgs boson at the LHC opened up a new possibility to obtain a precise understanding of the origin of mass and the structure of the vacuum. Several theories beyond the Standard Model predict an extended Higgs sector, with additional scalar particles. We outline the complementary search possibilities for these beyond Standard Model Higgs bosons at the LHC and at possible future high-energy collider facilities.
Jet counting and jet vetos are crucial analysis tools for many LHC searches. We can understand their properties from the distribution of the exclusive number of jets. LHC processes tend to show either a distinct staircase scaling or a Poisson scaling, depending on kinematic cuts. We illustrate our approach in a detailed study of jets in weak boson fusion Higgs production.
Preliminary results obtained by the CDF and D0 Collaborations on the Standard Model Higgs searches at the Tevatron Run II are discussed. The data that correspond to an integrated luminosity of > 150/pb are compared to theoretical expectations. Various final states involving the W and Z bosons production are examined, and new limits are set on the sigma[W(->enu/munu)H(->bb)] and sigma[H(->WW(*))] cross sections.
HiggsBounds 2.0.0 is a computer code which tests both neutral and charged Higgs sectors of arbitrary models against the current exclusion bounds from the Higgs searches at LEP and the Tevatron. As input, it requires a selection of model predictions, such as Higgs masses, branching ratios, effective couplings and total decay widths. HiggsBounds 2.0.0 then uses the expected and observed topological cross section limits from the Higgs searches to determine whether a given parameter scenario of a model is excluded at the 95% C.L. by those searches. Version 2.0.0 represents a significant extension …
The two-Higgs-doublet model contains extra Higgs bosons, with mass ranges spanning from several hundred GeV to about 1 TeV. We study the possible experimental searches for the neutral Higgs bosons of $A$ and $H$ at the future high-luminosity LHC runs. Besides of the conventional search modes that are inspired by the supersymmetric models, we discuss two search modes which were not quite addressed previously. They are the decay modes of $A\to hZ$ and $A/H \to t \bar t$. Thanks to the technique of tagging boosted objects of SM-like Higgs bosons and top quarks, we show the improved mass reaches f…
The LHC searches for the CP-odd Higgs boson is studied (with masses from 300 GeV to 1 TeV) in the context of the general two-Higgs-doublet model. With the discovery of the 125 GeV Higgs boson at the LHC, we highlight one promising discovery channel of the hZ. This channel can become significant after the global signal fitting to the 125 GeV Higgs boson in the general two-Higgs-doublet model. It is particularly important in the scenario where two CP-even Higgs bosons in the two-Higgs-doublet model have the common mass of 125 GeV. Since the final states involve a Standard-Model-like Higgs boson,…
We propose a novel method in that quark-gluon tagging of the jets emitted as initial state radiation (ISR) can boost searches of invisible Higgs from gluon fusion processes against irreducible electroweak vector boson productions. While quark ISR typically takes up a dominant portion than gluon in the background processes mainly by frequent quark-gluon initiated hard scatterings at the LHC, gluon ISR portion in the gluon fusion can be significantly larger in the central region of detector. Focusing on invisible Higgs searches using jet substructure variables capturing the new features, we demo…
We review the CLS method used by ATLAS and CMS to set exclusion limits on the mass of the Higgs boson. We investigate the impact of theoretical uncertainties of Higgs boson cross-sections due to higher order perturbative corrections and convolution with parton densities on exclusion limits. We illustrate the impact on limits of commonly used treatments of these uncertainties with a simulated Higgs search. We adopt a "worst- case scenario" for the perturbative uncertainties. We find that the statistical methods of ATLAS and CMS do not incorporate this specific uncertainty adequately.
The resummed transverse momentum distribution of supersymmetric Higgs bosons produced through gluon fusion at NLO+NLL is presented, including the exact quark and squark mass dependences. Considering various MSSM scenarios, we compare our results to previous ones within the POWHEG approach. We analyze the impact of the bottom loop which becomes the dominant contribution to the gluon fusion cross section for a wide range of the parameter space for the pseudo-scalar and heavy Higgs.
We analyze the Tevatron reach for neutral Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM), using current exclusion limits on the Standard Model Higgs. We study four common benchmark scenarios for the soft supersymmetry-breaking parameters of the MSSM, including cases where the Higgs decays differ significantly from the Standard Model, and provide projections for the improvements in luminosity and efficiency required for the Tevatron to probe sizeable regions of the $(m_A, \tanβ)$ plane.
Charged Higgs boson may be produced at hadron colliders via the decay of top quarks. At the LHC, The large production cross section of top quarks pairs will make it one of the earliest channels allowing to search for physics beyond the standard model. Assuming the decay $H^+ \to τ^+ν$, previous searches have so far considered only hadronic tau decays. Here we show that by using appropriate kinematical variables (transverse mass observables), leptonic tau decays can be used as well, for both observing and possibly measuring the mass of the charged Higgs boson. This can increase the overall expe…
Recently, the ATLAS and CMS experiments have reported the discovery of a Higgs like resonance at the LHC. The next analysis step will include the determination of its spin and CP quantum numbers or the form of its interaction Lagrangian channel-by-channel. We show how weak-boson-fusion Higgs production and associated ZH production can be used to separate different spin and CP states.
Precision measurements of the Higgs boson properties at the LHC provide relevant constraints on possible weak-scale extensions of the Standard Model (SM). In the context of the Minimal Supersymmetric Standard Model (MSSM) these constraints seem to suggest that all the additional, non-SM-like Higgs bosons should be heavy, with masses larger than about 400 GeV. This article shows that such results do not hold when the theory approaches the conditions for "alignment independent of decoupling", where the lightest CP-even Higgs boson has SM-like tree-level couplings to fermions and gauge bosons, in…
Recent results from the Tevatron are reported on Higgs boson searches in models beyond the standard model (SM). The models include fermiophobic Higgs bosons, the extension of the SM to a fourth generation of fermions, supersymmetric scenarios and heavy Higgs boson cascade decays.
Complex parameters in the MSSM lead to mixing and interference between the two heavier neutral CP-even and CP-odd Higgs states. These effects can become very large in the case of almost degenerate states. In a CP-violating benchmark scenario, we investigate phenomenological implications of such interferences in view of the LHC searches for heavy Higgs bosons decaying to a pair of $τ$-leptons and produced in gluon fusion and in association with b-quarks. Strongly destructive effects leave parameter regions unconstrained that would be regarded as excluded if no interference terms were taken into…
The mass of the Standard Model (SM) Higgs boson was constrained by the Large Electron-Positron (LEP) collider to be above 114.4 GeV. Simple extensions of the scalar sector like adding singlets and/or doublets allow the lightest Higgs to be much lighter via a reduction in its coupling to gauge bosons. Such a light Higgs could have evaded the LEP searches but could be detected at the Large Hadron Collider (LHC) in the process pp -> h j -> tau^+ tau^- j, where j is a resolved jet. We conclude that in some Beyond the Standard Model (BSM) extensions of the scalar sector, a very light Higgs state co…
We study the Higgs boson decays and production via gluon fusion at the LHC as a probe of two typical littlest Higgs models which introduce a top quark partner with different (even and odd) T-parity to cancel the Higgs mass quadratic divergence contributed by the top quark. For each model we consider two different choices for the down-type quark Yukawa couplings. We first examine the branching ratios of the Higgs boson decays and then study the production via gluon fusion followed by the decay into two photons or two weak gauge bosons. We find that the predictions can be quite different for dif…
The search for additional Higgs particles and the exact measurements of Higgs (self-) couplings is a major goal of future collider experiments. In this paper we investigate the possible sizes of new physics signals in these searches in the context of the $CP$-conserving two-Higgs doublet model of type II. Using current constraints from flavour, electroweak precision, and Higgs signal strength data, we determine the allowed sizes of the triple Higgs couplings and the branching fractions of the heavy Higgs bosons into lighter Higgs bosons. Identifying the observed Higgs resonance with the light …
The usually considered vacuum of the two-Higgs-doublet model (2HDM) could be unstable if it locates at a local but not global minimum (GM) of the scalar potential. By requiring the vacuum to be a GM, we obtain an additional constraint, namely the GM constraint, on the scalar potential. In this work, we explore the GM constraint on the $CP$-conserving general 2HDM. This constraint is found to put limits on the soft $\mathbb{Z}_2$ breaking mass parameter $m_{12}^2$ and also squeeze the heavy $CP$-even Higgs boson mass into larger values for the $m_{12}^2< 0$ case. Combined with the current globa…
The spectrum of supersymmetric theories with R-parity violation are much more weakly constrained than that of supersymmetric theories with a stable neutralino. We investigate the signatures of supersymmetry at the LHCb experiment in the region of parameter space where the neutralino decay leaves a displaced vertex. We find sensitivity to squark production up to squark masses of order 1 TeV. We note that if the Higgs decays to neutralinos in this scenario, LHCb should see the lightest Higgs boson before ATLAS and CMS.
In high energy hadronic collisions, a general CP-violating Higgs boson $Φ$ with accompanying jets can be efficiently produced via gluon fusion, which is mediated by heavy quark loops. In this letter we study the dominant sub-channel $ gg \to Φggg$ of the gluon fusion production process with triple real emission corrections at order $α_s^5$. We go beyond the heavy top limit approximation and include the full mass dependence of the top- and bottom-quark contributions. Furthermore, we show within a toy-model scenario that bottom-quark loop contributions in combination with large values of $\tan β…
In these proceedings, we present results for Higgs production at the LHC via gluon fusion with triple real emission corrections and the validity range of the heavy-top effective theory approximation for this process. For a general CP-violating Higgs boson, we show that bottom-quark loop corrections in combination with large values of $\tan β$ significantly distort differential distributions.
The parameter space of the MSSM can be probed via many avenues, such as by pre- cision measurements of the couplings of the ~126 GeV Higgs boson, as well as the direct searches for SUSY partners. We examine the connection between these two collider observables at the LHC and ILC in the 19/20-parameter p(henomenological)MSSM. Within this scenario, we address two questions: (i) How will potentially null direct searches for SUSY at the LHC influence the predicted properties of the lightest SUSY Higgs boson? (ii) What can be learned about the properties of the superpartners from precision measurem…
We analyze the Tevatron and Large Hadron Collider (LHC) reach for the Higgs sector of the Minimal Supersymmetric Standard Model (MSSM) in the presence of explicit CP-violation. Using the most recent studies from the Tevatron and LHC collaborations, we examine the CPX benchmark scenario for a range of CP-violating phases in the soft trilinear and gluino mass terms and compute the exclusion/discovery potentials for each collider on the $(M_{H^+}, \tanβ)$ plane. Projected results from Standard Model (SM)-like, non-standard, and charged Higgs searches are combined to maximize the statistical signi…
In the MSSM weak boson fusion produces the two CP even Higgs bosons with a combined strength equivalent to the production of the Standard Model Higgs boson. The tau tau decay mode --- supplemented by gamma gamma --- provides a highly significant signal for at least one of the CP even Higgs bosons at the LHC with reasonable luminosity. The accessible parameter space covers the entire physical range which will be left unexplored by LEP2.
We present here the results for Higgs and Supersymmetry prospective searches at the Large Hadron Collider. We show that for one year at high luminosity, Standard Model and MSSM Higgs should be observed within the theoretically expected mass range. MSUGRA and restricted phenomenological MSSM searches lead to discovery of up to 2.5 TeV squarks and gluinos.
We review the most relevant LHC searches at $\sqrt{s}$ = 8 TeV looking for low mass bosons arising from exotic decay of the Standard Model Higgs and highlighting their impact on both supersymmetric and not supersymmetric Beyond the Standard Model scenarios.
In this paper we study the possible searches at colliders using Vector Boson Fusion topology in the context of Simplified Models signatures. We examine the possible physics reach of these searches with regard to monojet-type searches, and determine how these two signatures are complementary.
Latest results from the combined data of the four LEP experiments ALEPH, DELPHI, L3 and OPAL on Higgs boson searches in extensions of the Standard Model (SM) are presented.
In this talk, I discuss some aspects of Higgs searches at future colliders, particularly comparing and contrasting the capabilities of LHC and Next Linear Collider (NLC), including the aspects of Higgs searches in supersymmetric theories. After this, I will discuss how the search and study of sparticles other than the Higgs can give information about the parameters of the Minimal Supersymmetric Standard Model (MSSM).
The latest preliminary combined results of the Higgs boson searches from the LEP experiments ALEPH, DELPHI, L3 and OPAL are presented. A general scan of the MSSM parameters is performed and leads to stringent lower mass limits and for the first time excludes low tan(beta) values.
Extensive searches for Higgs bosons and other new phenomena predicted by extensions of the Standard Model have been performed at LEP. A summary is given reviewing the principal aspects and presenting a selection of results.
We discuss the constraints on Supersymmetry in the Higgs sector arising from LHC searches, rare B decays and dark matter direct detection experiments. We show that constraints derived on the mass of the lightest h0 and the CP-odd A0 bosons from these searches are covering a broader fraction of the SUSY parameter space compared to searches for strongly interacting supersymmetric particle partners. We discuss the implications of a mass determination in the range 123 < Mh < 127 GeV, inspired by the intriguing hints reported by the ATLAS and CMS collaborations, as well as those of a non-observatio…
The implications of the LHC SUSY searches as well as the discovery of a new bosonic state compatible with the lightest Higgs boson will be discussed in the context of constrained and general MSSM scenarios. Exploring the MSSM through the Higgs sector is an alternative and complementary path to direct searches, and tight constraints on the MSSM parameter space can be obtained.
The Higgs boson sector of the Minimal Supersymmetric Standard Model (MSSM) is investigated in a uniform way in the framework of the three most prominent soft SUSY-breaking scenarios, mSUGRA, mGMSB and mAMSB, especially concerning the Higgs searches at LEP2.
The LEP experiments completed data-taking in November 2000. New preliminary combined results of the four LEP experiments ALEPH, DELPHI, L3 and OPAL are presented for various Higgs boson searches.
The LEP era has brought immense progress in searches for Higgs bosons over the last 12 years which will guide searches at future colliders. The evolution of the Higgs boson mass limits are reviewed with the focus on results from general parameter scans in the Minimal Supersymmetric extension of the Standard Model (MSSM) in contrast to the so-called benchmark limits. The hint for a Standard Model (SM) Higgs boson of 115.6 GeV can also be interpreted as a preference for a Higgs boson of that mass in the MSSM. Further small data excesses allow the hypothesis that the neutral Higgs bosons of the M…
I start with a brief summary of Higgs Mechanism and supersymmetry. Then I discuss the theoretical constraints, current limits and search strategies for Higgs boson(s) at LHC - first in the SM and then in the MSSM. Finally, I discuss the analogous constraints and search strategies for the superparticles, concentrating on the minimal supergravity model. Recent advances in identifying the most promising channels for Higgs and SUSY searches are emphasized.
Since the discovery of a Higgs boson at the LHC and the measurement of many of its branching ratios, there have been numerous studies exploring the restrictions these results place on the parameter space of two Higgs doublet models. We extend these results to include the full data set and study the expected sensitivity that can be obtained with 300 and 3000 inverse femptobarn of integrated luminosity. We consider searches for a heavy Standard Model Higgs boson, with a mass ranging from 200 to 400 GeV, and show that the non-observation of such a Higgs boson can substantially narrow the allowed …
Direct production of electroweakly charged states may not produce the high energy jets or the significant missing energy required in many new physics searches at the LHC. However, because these states produce leptons, they are still potentially detectable over the sizeable Standard Model backgrounds. We show that current LHC Higgs searches, particularly in the WW* and ZZ* channels, are sensitive to new electroweak states, such as supersymmetric charginos or neutralinos. Indeed, the 1.7 fb^{-1} Higgs searches can provide the strongest limits in certain regions of parameter space, extending the …
In this note we compare the latest 1.04 fb^{-1} LHC searches for squarks and gluinos from jets and missing transverse momentum (MET) with constraints arising from the LEP Higgs bound. For General Gauge Mediation models with moderate values of tan(beta) we find that the zero-lepton MET searches of supersymmetry at the LHC are only starting to be competitive with the Higgs bounds from LEP. From this perspective and for such models, the SUSY searches at the LHC are still very much in the beginning.
Searches for invisible Higgs decays at the Large Hadron Collider constrain dark matter Higgs-portal models, where dark matter interacts with the Standard Model fields via the Higgs boson. While these searches complement dark matter direct-detection experiments, a comparison of the two limits depends on the coupling of the Higgs boson to the nucleons forming the direct-detection nuclear target, typically parameterized in a single quantity $f_N$. We evaluate $f_N$ using recent phenomenological and lattice-QCD calculations, and include for the first time the coupling of the Higgs boson to two nuc…
We study the pair production of fourth generation neutrinos from the decay of an on-shell Higgs produced by gluon fusion. In a fourth generation scenario, the Higgs branching fraction into fourth generation neutrinos may be quite large. In the case that the unstable heavy neutrinos are a mixed Majorana and Dirac state, neutrinos pair-produced from Higgs decay will yield a substantial number of like-sign dilepton events. In this article we use inclusive like-sign dilepton searches from hadron colliders to constrain the theoretical parameter space of fourth generation leptons.
