Triple Higgs Production Research Articles

Bosonic multi-Higgs correlations beyond leading order

The production of multiple Higgs bosons at the LHC and beyond is a strong test of the mechanism of electroweak symmetry breaking. Taking inspiration from recent experimental efforts to move toward limits on triple-Higgs production at the Large Hadron Collider, we consider generic bosonic deviations of HH and HHH production from the Standard Model in the guise of Higgs effective field theory (HEFT). Including one-loop radiative corrections within the HEFT and going up to O(p4) in the momentum expansion, we provide a detailed motivation of the parameter range that the LHC (and future hadron colliders) can explore, through accessing nonstandard coupling modifications and momentum dependencies that probe Higgs boson nonlinearities. In particular, we find that radiative corrections can enhance the sensitivity to Higgs self-coupling modifiers and HEFT-specific momentum dependencies can vastly increase triple-Higgs production, thus providing further motivation to consider these processes during the LHC’s high-luminosity phase. Published by the American Physical Society 2024

Double and triple Higgs boson production to probe the electroweak phase transition

The production of three Higgs bosons could be a stretch goal for the LHC and a strategic case for future colliders. In this work, we analyse the phenomenological prospects of (neutral) triple Higgs compared to di-Higgs boson production, for a range of Higgs-sector extensions from a strong first-order electroweak phase transition perspective. In parallel, we include constraints from existing exotics and Higgs boson measurements that further limit the parameter space of such models. Resonance contributions offer large modifications in particular for triple Higgs production, albeit starting from a small SM expectation. With enhancements of order 40 over the SM, however, experimental efforts to obtain limits at the HL-LHC are well motivated and well placed. This is further highlighted by the potential of these processes to inform the investigation of the thermal history of our Universe. Published by the American Physical Society 2024

Constraints on the trilinear and quartic Higgs couplings from triple Higgs production at the LHC and beyond

AbstractExperimental information on the trilinear Higgs boson self-coupling $$\kappa _3$$ κ 3 and the quartic self-coupling $$\kappa _4$$ κ 4 will be crucial for gaining insight into the shape of the Higgs potential and the nature of the electroweak phase transition. While Higgs pair production processes provide access to $$\kappa _3$$ κ 3 , triple Higgs production processes, despite their small cross sections, will provide valuable complementary information on $$\kappa _3$$ κ 3 and first experimental constraints on $$\kappa _4$$ κ 4 . We investigate triple Higgs boson production at the HL-LHC, employing efficient Graph Neural Network methodologies to maximise the statistical yield. We show that it will be possible to establish bounds on the variation of both couplings from the HL-LHC analyses that significantly go beyond the constraints from perturbative unitarity. We also discuss the prospects for the analysis of triple Higgs production at future high-energy lepton colliders operating at the TeV scale.

Disentangling the high- and low-cutoff scales via the trilinear Higgs couplings in the type-I two-Higgs-doublet model

The type-I two-Higgs-doublet model in the inverted Higgs scenario can retain the theoretical stability all the way up to the Planck scale. The Planck-cutoff scale, $\Lambda_{\rm cut}^{\rm Planck}$, directly impacts the mass spectra such that all the extra Higgs boson masses should be light below about 160 GeV. However, the observation of the light masses of new Higgs bosons does not indicate the high cutoff scale because a low cutoff scale can also accommodate the light masses. Over the viable parameter points that satisfy the theoretical requirements and the experimental constraints, we show that the trilinear Higgs couplings for low $\Lambda_{\rm cut}$ are entirely different from those for the Planck-cutoff scale. The most sensitive coupling to the cutoff scale is from the $h$-$h$-$h$ vertex, where $h$ is the lighter CP-even Higgs boson at a mass below 125 GeV. Among the multi-Higgs productions mediated by Higgs bosons, the gluon fusion processes of $gg \to h h $ and $gg \to AA$ are insensitive to the cutoff scale, yielding a small variation of $\mathcal{O}(1)\,{\rm fb}$ according to $\Lambda_{\rm cut}$. The smoking-gun signature is from the triple Higgs production of $q\bar{q}' \to W^* \to H^\pm hh$, which solely depends on the $h$-$h$-$h$ vertex. The cross section for $\Lambda_{\rm cut}=1\,{\rm TeV}$ is about $10^3$ times larger than that for the Planck-cutoff scale. Since the decay modes of $H^\pm \to W^* h/W^* A$ and $h/A \to bb$ are dominant, the process yields the $6b+\ell\nu$ final state, which enjoys an almost background-free environment. Consequently, the precision measurement of $pp \to H^\pm hh$ can probe the cutoff scale of the model.

Benchmark planes for Higgs-to-Higgs decays in the NMSSM

We present benchmark planes (or lines) with cross sections via gluon fusion for the processes Hrightarrow h+H_{S}, resonant Higgs pair and triple Higgs production, A rightarrow h+(A_S rightarrow gamma gamma ), A rightarrow Z+ h and A rightarrow Z+ H_{S} within the Next-to-Minimal Supersymmetric Standard Model. Moreover we propose new searches for Hrightarrow h+(H_{S} rightarrow t{bar{t}}), A rightarrow Z+ (H_{S}rightarrow h+h) and A rightarrow Z+ (H_{S}rightarrow t{bar{t}}) for which possible cross sections are given. These allow the experimental collaborations to verify in the future which search channels cover yet unexplored regions of the parameter space. Expressions for the dominant contributions to trilinear Higgs couplings and Higgs–Z couplings are discussed which allow to identify the dominant processes contributing to a given final state.

Measuring Higgs boson self-couplings with 2 \u2192 3 VBS processes

We study the measurement of Higgs boson self-couplings through 2 → 3 vector boson scattering (VBS) processes in the framework of Standard Model effective field theory (SMEFT) at both proton and lepton colliders. The SMEFT contribution to the amplitude of the 2 → 3 VBS processes, taking WLWL → WLWLh and WLWL → hhh as examples, exhibits enhancement with the energy frac{{mathcal{A}}^{mathrm{BSM}}}{{mathcal{A}}^{mathrm{SM}}}sim frac{E^2}{Lambda^2} , which indicates the sensitivity of these processes to the related dimension-six operators in SMEFT. Simulation of the full processes at both hadron and lepton colliders with a variety of collision energies are performed to estimate the allowed region on c6 and {c}_{Phi_1} . Especially we find that, with the help of exclusively choosing longitudinal polarizations in the final states and suitable pT cuts, WWh process is as important as the more widely studied triple Higgs production (hhh) in the measurement of Higgs self-couplings. Our analysis indicates that these processes can play important roles in the measurement of Higgs self-couplings at future 100 TeV pp colliders and muon colliders. However, their cross sections are generally tiny at low energy machines, which makes them much more challenging to explore.

Multi-Higgs boson production probes Higgs sector flavor

We demonstrate that multiple-Higgs production at the LHC is the most sensitive probe of first and second-generation quark flavor in the Higgs sector. In models where new scalars couple to light quarks, gigantic di-Higgs and even sizable tri-Higgs production rates can be obtained, which can be used to either discover or severely constrain such theories. As an example, we show that the most stringent bounds on enhanced interactions of the $125\,\textrm{GeV}$ Higgs to the down quark in extended Higgs sectors are obtained by looking for the extra Higgs bosons that provide for such enhancements using the di-Higgs and $Zh$ topologies. In this context, we set new limits on the 125 GeV Higgs coupling to the down quark as strong as $\lambda_{hd\bar{d}} \lesssim 30 \lambda_{hd\bar{d}}^{\textrm{SM}}$ -- a dramatic improvement over previously available bounds. Regarding second-generation quark flavor, we obtain new limits in the coupling to strange as strong as $\lambda_{hs\bar{s}} \lesssim 10 \lambda_{hs\bar{s}}^{\textrm{SM}}$. In addition, we show that the currently unexplored triple-Higgs production topology could be a potential discovery channel of a wide variety of extended Higgs sectors at the LHC, including not only models where extra Higgses couple to light quarks, but also popular theories where they have preferential couplings to the the top.

Testing anomalous H-W couplings and Higgs self-couplings via double and triple Higgs production at e^+e^- colliders

In the present work we study the implications at the future e^+e^- colliders of the modified interaction vertices WWH, WWHH, HHH and HHHH within the context of the non-linear effective field theory given by the Electroweak Chiral Lagrangian. These vertices are given by four parameters, a, b, kappa _3 and kappa _4, respectively, that are independent and without any constraint from symmetry considerations in this non-linear effective Lagrangian context, given the fact the Higgs field is a singlet. This is in contrast to the Standard Model, where the vertices are related by V_{WWH}^mathrm{SM}=v V_{WWHH}^mathrm{SM} and V_{HHH}^mathrm{SM}=v V_{HHHH}^mathrm{SM}, with v=246 GeV. We investigate the implications of the absence of these relations in the Electroweak Chiral Lagrangian case. We explore the sensitivity to these Higgs anomalous couplings in the two main channels at these colliders: double and triple Higgs production (plus neutrinos). Concretely, we study the access to a and b in e^+e^- rightarrow HH nu {bar{nu }} and the access to kappa _3 and kappa _4 in e^+e^- rightarrow HHH nu {bar{nu }}. Our study of the beyond the Standard Model couplings via triple Higgs boson production at e^+e^- colliders is novel and shows for the first time the possible accessibility to the quartic Higgs self-coupling.

Determining the shape of the Higgs potential at future colliders

Although the Higgs boson has been discovered, its self-couplings are poorly constrained. This leaves the nature of the Higgs boson undetermined. Motivated by different Higgs potential scenarios other than the Landau-Ginzburg type in the standard model, we systematically organize various new physics scenarios -- elementary Higgs, Nambu-Goldstone Higgs, Coleman-Weinberg Higgs, and Tadpole-induced Higgs, etc. We find that double-Higgs production at the 27 TeV high energy LHC can be used to discriminate different Higgs potential scenarios, while it is necessary to use triple-Higgs production at a future 100 TeV proton-proton collider to fully determine the shape of the Higgs potential.

Triple Higgs production at hadron colliders at NNLO in QCD

In this work we analyse the triple Higgs boson production cross section at hadron colliders via gluon fusion, and present for the first time the full set of QCD NNLO corrections in the heavy top limit. In order to account for finite top mass effects we perform two different reweighting procedures, and study the dependence of the result on the choice of the approximation. Combining the most accurate predictions available to date, we present the following result for the total NNLO cross section for triple Higgs boson production at a 100 TeV collider: {sigma}_{mathrm{NNLO}}={5.56}_{-6%}^{+5%} ± 20% fb, where the first uncertainty is an estimate for higher order effects from scale variations, while the last one is an estimate for the missing finite top mass effects.

Constraints on the quartic Higgs self-coupling from double-Higgs production at future hadron colliders

We study the indirect constraints on the quartic Higgs self-coupling that arise from double-Higgs production at future hadron colliders. To this purpose, we calculate the two-loop contributions to the gg → hh amplitudes that involve a modified h4 vertex. Based on our results, we estimate the reach of a pp collider operating at 27 TeV and 100 TeV centre-of-mass energy in constraining the cubic and quartic Higgs self-couplings by measurements of double-Higgs and triple-Higgs production in gluon-fusion.

Probing the scalar potential via double Higgs boson production at hadron colliders

We present a sensitivity study on the cubic and quartic self couplings in double Higgs production via gluon fusion at hadron colliders. Considering the relevant operators in the Standard Model Effective Field Theory up to dimension eight, we calculate the dominant contributions up to two-loop level, where the first dependence on the quartic interaction appears. Our approach allows to study the independent variations of the two self couplings and to clearly identify the terms necessary to satisfy gauge invariance and to obtain UV-finite results order by order in perturbation theory. We focus on the boverline{b}gamma gamma signature for simplicity and provide the expected bounds for the cubic and quartic self couplings at the 14 TeV LHC with 3000 fb−1 (HL-LHC) and for a future 100 TeV collider (FCC-100) with 30 ab−1. We find that while the HL-LHC will provide very limited sensitivity on the quartic self coupling, precision measurements of double Higgs production at a FCC-100 will offer the opportunity to set competitive bounds. We show that combining information from double and triple Higgs production leads to significantly improved prospects for the determination of the quartic self coupling.

Constraining the Higgs self-couplings at e+e\u2212 colliders

We study the sensitivity to the shape of the Higgs potential of single, double, and triple Higgs production at future e+e− colliders. Physics beyond the Standard Model is parameterised through the inclusion of higher-dimensional operators (Φ†Φ−v2/2)n/Λ(2n−4) with n = 3, 4, which allows a consistent treatment of independent deviations of the cubic and quartic self-couplings beyond the tree level. We calculate the effects induced by a modified potential up to one loop in single and double Higgs production and at the tree level in triple Higgs production, for both Z boson associated and W boson fusion production mechanisms. We consider two different scenarios. First, the dimension six operator provides the dominant contribution (as expected, for instance, in a linear effective-field-theory (EFT)); we find in this case that the corresponding Wilson coefficient can be determined at mathcal{O}left(10%right) accuracy by just combining accurate measurements of single Higgs cross sections at sqrt{widehat{s}}=240-250 GeV and double Higgs production in W boson fusion at higher energies. Second, both operators of dimension six and eight can give effects of similar order, i.e., independent quartic self-coupling deviations are present. Constraints on Wilson coefficients can be best tested by combining measurements from single, double and triple Higgs production. Given that the sensitivity of single Higgs production to the dimension eight operator is presently unknown, we consider double and triple Higgs production and show that combining their information colliders at higher energies will provide first coarse constraints on the corresponding Wilson coefficient.

Sources of Charged Higgs Pair through Double or Triple Higgs Production at Linear Colliders

The production of triple Higgs (H+H-H0), (H+H-h0) and pairwise charged Higgs boson (H+H-) is studied in the context of future linear colliders within the two-Higgs-doublet model (2HDM) type II. The aim is to compare sources of charged Higgs pair through the above processes, that is, double and triple Higgs production. Cross sections are calculated at the leading order in 2HDM type II and Minimal Supersymmetric Standard Model (MSSM). Several orders of magnitude (~104) enhancement are observed in 2HDM compared to MSSM, while no sizable enhancement is seen in muon collider versus electron-positron collider. The analysis is based on a heavy charged Higgs with mass above 500 GeV. It is found that double charged Higgs production cross section (being the same in 2HDM and MSSM) is few femtobarns, while the triple Higgs production cannot exceed a fraction of femtobarn within the parameter space under study.

Associated production of the doubly-charged scalar pair with the Higgs boson in the Georgi–Machacek model at the ILC

Abstract Besides the SM-like Higgs boson h , the Georgi–Machacek (GM) model predicts the existence of doubly-charged Higgs bosons H 5 ± ± in the 5-plet representation, which can be seen the typical particles in this model. We first used the latest Higgs boson diphoton signal strength data to find the allowed region at 2 σ confidence level on the plane of the scalar mass values m H and the triple scalar coupling parameter g h H H , and then focus on the study of the triple Higgs production process e + e − → h H 5 + + H 5 − − at the future International Linear collider (ILC). Our numerical results show that, the values of the production cross section are very sensitive to the triple Higgs coupling strength g h H H and can reach the level several fb in the reasonable parameter space. Considering the same-sign diboson decay H 5 ± ± → W ± W ± , the expected discovery reach at the future ILC experiments are also studied.

Self-coupling of the Higgs boson in the processespp→ZHHH+Xandpp→WHHH+X

To gain some sense about the likelihood of measuring the Higgs boson quartic coupling, we calculate the contribution to the triple Higgs production cross section from the subprocesses $q\bar{q}\to ZHHH$ and $q\bar{q}'\to WHHH$. Our results illustrate that determining this coupling, or even providing experimental evidence that it exists, will be very difficult.

Probing Higgs boson self-interactions in proton-proton collisions at a center-of-mass energy of 100 TeV

We present a phenomenological study of triple-Higgs production in which we estimate the prospects for measuring the form of the Higgs potential at future circular collider projects. We analyze proton-proton collisions at a center-of-mass energy of 100 TeV and focus on two different signatures in which the final state is made of four b-jets and either a pair of photons or a pair of tau leptons. We study the resulting sensitivity on the Higgs cubic and quartic self-interactions and investigate how it depends on the b-tagging, tau-tagging and photon resolution performances of detectors that could be designed for these future machines. We then discuss possible luminosity goals for future 100 TeV collider projects that would allow for a measurement of the Higgs potential and its possible departures from the Standard Model expectation.

Probing triple-Higgs productions via4b2γdecay channel at a 100 TeV hadron collider

The quartic self-coupling of the Standard Model Higgs boson can only be measured by observing the triple-Higgs production process, but it is challenging for the Large Hadron Collider (LHC) Run 2 or International Linear Collider (ILC) at a few TeV because of its extremely small production rate. In this paper, we present a detailed Monte Carlo simulation study of the triple-Higgs production through gluon fusion at a 100 TeV hadron collider and explore the feasibility of observing this production mode. We focus on the decay channel $HHH\rightarrow b\bar{b}b\bar{b}\gamma\gamma$, investigating detector effects and optimizing the kinematic cuts to discriminate the signal from the backgrounds. Our study shows that, in order to observe the Standard Model triple-Higgs signal, the integrated luminosity of a 100 TeV hadron collider should be greater than $1.8\times 10^4$ ab$^{-1}$. We also explore the dependence of the cross section upon the trilinear ($\lambda_3$) and quartic ($\lambda_4$) self-couplings of the Higgs. We find that, through a search in the triple-Higgs production, the parameters $\lambda_3$ and $\lambda_4$ can be restricted to the ranges $[-1, 5]$ and $[-20, 30]$, respectively. We also examine how new physics can change the production rate of triple-Higgs events. For example, in the singlet extension of the Standard Model, we find that the triple-Higgs production rate can be increased by a factor of $\mathcal{O}(10)$.

Top-quark mass effects in double and triple Higgs production in gluon-gluon fusion at NLO

The observation of double and triple scalar boson production at hadron colliders could provide key information on the Higgs self couplings and the potential. As for single Higgs production the largest rates for multiple Higgs production come from gluon-gluon fusion processes mediated by a top-quark loop. However, at variance with single Higgs production, top-quark mass and width effects from the loops cannot be neglected. Computations including the exact top-quark mass dependence are only available at the leading order, and currently predictions at higher orders are obtained by means of approximations based on the Higgs-gluon effective field theory (HEFT). In this work we present a reweighting technique that, starting from events obtained via the MC@NLO method in the HEFT, allows to exactly include the top-quark mass and width effects coming from one- and two-loop amplitudes. We describe our approach and apply it to double Higgs production at NLO in QCD, computing the needed one-loop amplitudes and using approximations for the unknown two-loop ones. The results are compared to other approaches used in the literature, arguing that they provide more accurate predictions for distributions and for total rates as well. As a novel application of our procedure we present predictions at NLO in QCD for triple Higgs production at hadron colliders.

Triple Higgs boson production at ILC in the Higgs triplet model

Besides the Standard Model (SM)-like Higgs boson h, the Higgs Triplet Model (HTM) predicts the existence of charged and doubly charged Higgs bosons (H±and H±±). In this paper, we focus on the study of the triple Higgs production at the International Linear Collider (ILC): e-e+→hH+H-and e-e+→hH++H–. We present the production cross-sections and discuss the relevant SM backgrounds. Our numerical results show that, with reasonable parameter values, the values of the cross-sections for two processes can reach the level several fb and tens of fb, respectively. Due to large production cross-section and small SM background, the possible signals of H±and H±±might be detected via these processes in the future ILC experiments.