Double Higgs Boson Production Research Articles

Double Higgs boson production via photon fusion at muon colliders within the triplet Higgs model

In this paper, we present predictions for scattering cross section the of Higgs boson pair production via photon fusion at future muon colliders, focusing specifically the production processes μ+μ−→γγ→h0h0,A0A0. We investigated the impact of three choices the photon structure functions on cross-section predictions for a range model input parameters within the theoretical framework of the Higgs triplet model [; ; ; ]. Published by the American Physical Society 2024

The Higgs boson couplings: past, present, and future. The relationships between Higgs boson and other known particles as measured by current and future experiments

The discovery of the Higgs boson, a fundamental particle of the Standard Model, at the Large Hadron Collider (LHC) in 2012, marked a monumental milestone in the field of particle physics. Since then, extensive research has been conducted to understand the properties and interactions of the Higgs boson, particularly its couplings with other known particles. This article provides a review of the past, present, and future measurements of the Higgs boson couplings, with a focus on the most recent experimental developments. It discusses the experimental techniques and methods used to study the Higgs boson couplings, including the production and decay channels employed in various experiments. The article highlights the important relationships between the Higgs boson and other known particles, including the gauge bosons (W and Z bosons), quarks, and leptons and the Higgs boson itself, through its self-interaction. After discussing the channels used by ATLAS and CMS collaborations to measure the Higgs boson coupling to the other standard model particles, the article will present an overview of the latest results obtained at the LHC, commenting on how various measurements have evolved over time along with a better comprehension of the detectors and ever more refined analysis techniques. Future collider developments and expectation for the measurement of the Higgs boson couplings and double-Higgs boson production with increased precision and accuracy will be discussed along with the main challenges faced by future experiments.

Analytic approximations of 2 → 2 processes with massive internal particles

We consider two-loop corrections to 2 → 2 scattering processes with massive particles in the final state and massive particles in the loop. We discuss the combination of analytic expansions in the high-energy limit and for small Mandelstam variable t. For the example of double Higgs boson production we show that the whole phase space can be covered and time-consuming numerical integrations can be avoided.

Top quark mass corrections to single and double Higgs boson production in gluon fusion

In this talk we discuss recent computations of the top quark mass dependence of QCD amplitudes describing Higgs boson production in gluon fusion. We compute terms in the expansion for a large top quark mass, which reduces the Feynman diagrams to products of massless integrals and massive tadpole integrals which contain the top mass dependence. In particular we discuss the real and virtual corrections to double Higgs production at NNLO, and the virtual corrections to single Higgs production at N3LO.

Double Higgs boson production and Higgs self-coupling extraction at CLIC

The Compact Linear Collider (CLIC) is a future electron–positron collider that will allow measurements of the trilinear Higgs self-coupling in double Higgs boson events produced at its high-energy stages with collision energies from sqrt{s} = 1.4 to 3 TeV. The sensitivity to the Higgs self-coupling is driven by the measurements of the cross section and the invariant mass distribution of the Higgs-boson pair in the W-boson fusion process, text {e}^{+}text {e}^{-}rightarrow {text {H}text {H}nu bar{nu }}. It is enhanced by including the cross-section measurement of ZHH production at 1.4 TeV. The expected sensitivity of CLIC for Higgs pair production through W-boson fusion is studied for the decay channels mathrm{b}bar{mathrm{b}}mathrm{b}bar{mathrm{b}} and mathrm{b}bar{mathrm{b}}mathrm{W}mathrm{W}^{*} using full detector simulation including all relevant backgrounds at sqrt{s} = 1.4 TeV with an integrated luminosity of mathcal {L} = 2.5 ab^{-1} and at sqrt{s} = 3 TeV with mathcal {L} = 5 ab^{-1}. Combining text {e}^{+}text {e}^{-}rightarrow {text {H}text {H}nu bar{nu }} and ZHH cross-section measurements at 1.4 TeV with differential measurements in text {e}^{+}text {e}^{-}rightarrow {text {H}text {H}nu bar{nu }} events at 3 TeV, CLIC will be able to measure the trilinear Higgs self-coupling with a relative uncertainty of -8% and +11% at 68% C.L., assuming the Standard Model. In addition, prospects for simultaneous constraints on the trilinear Higgs self-coupling and the Higgs-gauge coupling HHWW are derived based on the {text {H}text {H}nu bar{nu }} measurement.

E+e−→hhZ in the B−L symmetric SSM

The double Higgs boson production through $e^{+}e^-\rightarrow hhZ$ is analyzed in the minimal supersymmetric extension of the Standard Model(SM) with the local gauge symmetry $U(1)_{B-L}$, where $h$ denotes the lightest Higgs boson with 125 GeV. Considering the constraints from the updated prediction data, we find that the production cross section of this process in the model depends on some parameters strongly.

Double Higgs boson production as an exclusive probe for a sequential fourth generation with wrong-sign Yukawa couplings

It has been shown that the data from the Large Hadron Collider (LHC) does not rule out a chiral sequential fourth generation of fermions that obtain their masses through an identical mechanism as the other three generations do. However, this is possible only if the scalar sector of the Standard Model is suitably enhanced, like embedding it in a type-II two-Higgs doublet model. In this article, we try to show that double Higgs production (DHP) can unveil the existence of such a hidden fourth generation in a very efficient way. While the DHP cross-section in the SM is quite small, it is significantly enhanced with a fourth generation. We perform a detailed analysis of the dependence of the DHP cross-section on the model parameters, and show that either a positive signal of DHP is seen in the early next run of the LHC, or the model is ruled out.

Double Higgs boson production at NLO: combining the exact numerical result and high-energy expansion

We consider the next-to-leading order QCD corrections to Higgs boson pair production, using our recent calculation of the form factors in the high-energy limit. We compute the virtual corrections to the partonic cross section, applying Padé approximations to extend the range of validity of the high-energy expansion. This enables us to compare to the exact numerical calculation in a significant part of the phase space and allows us to extend the virtual matrix element grid, based on the exact numerical calculation, to larger values of the (partonic) transverse momentum of the Higgs boson, which is important for boosted Higgs studies. Improved predictions for hadron colliders with centre-of-mass energies of 14 TeV and 100 TeV are presented. The updated grid is made publicly available.

Double Higgs boson production at e+e− colliders in the two-Higgs-doublet model

We study the double Higgs boson production processes $e^+e^- \to hh f\bar{f}$ ($f\neq t$) with $h$ being the 125 GeV Higgs boson in the two-Higgs-doublet model with a softly-broken $Z_2$ symmetry. The cross section can be significantly enhanced, typically a few hundreds percent, as compared to the standard model prediction due to resonant effects of heavy neutral Higgs bosons, which becomes important in the case without the alignment limit. We find a strong correlation between the enhancement factor of the cross section and the scaling factor of the $hf\bar{f}$ couplings under constraints from perturbative unitarity, vacuum stability and current experimental data at the LHC as well as the electroweak precision data.

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.

Double Higgs boson production at NLO in the high-energy limit: complete analytic results

We compute the NLO virtual corrections to the partonic cross section of gg → HH, in the high energy limit. Finite Higgs boson mass effects are taken into account via an expansion which is shown to converge quickly. We obtain analytic results for the next-to-leading order form factors which can be used to compute the cross section. The method used for the calculation of the (non-planar) master integrals is described in detail and explicit results are presented.

Double elementary Goldstone Higgs boson production in future linear colliders

The Elementary Goldstone Higgs (EGH) model is a perturbative extension of the Standard Model (SM), which identifies the EGH boson as the observed Higgs boson. In this paper, we study pair production of the EGH boson in future linear electron positron colliders. The cross-sections in the TeV region can be changed to about −27%, 163% and −34% for the [Formula: see text], [Formula: see text] and [Formula: see text] processes with respect to the SM predictions, respectively. According to the expected measurement precisions, such correction effects might be observed in future linear colliders. In addition, we compare the cross-sections of double SM-like Higgs boson production with the predictions in other new physics models.

Statistical approach to Higgs boson couplings in the standard model effective field theory

We perform a parameter fit in the Standard Model Effective Field Theory (SMEFT) with an emphasis on using regularized linear regression to tackle the issue of the large number of parameters in the SMEFT. In regularized linear regression a positive definite function of the parameters of interest is added to the usual cost function. A cross-validation is performed to try to determine the optimal value of the regularization parameter to use, but it selects the Standard Model (SM) as the best model to explain the measurements. Nevertheless as proof of principle of this technique we apply it to fitting Higgs boson signal strengths in SMEFT, including the latest Run-2 results. Results are presented in terms of the eigensystem of the covariance matrix of the least squares estimators as it has a degree model-independent to it. We find several results in this initial work: the SMEFT predicts the total width of the Higgs boson to be consistent with the SM prediction; the ATLAS and CMS experiments at the LHC are currently sensitive to non-resonant double Higgs boson production. Constraints are derived on the viable parameter space for electroweak baryogenesis in the SMEFT, reinforcing the notion that a first order phase transition requires fairly low scale Beyond the SM physics. Finally, we study which future experimental measurements would give the most improvement on the global constraints on the Higgs sector of the SMEFT.

Higgs Physics at CMS

The discovery of the Standard Model Higgs boson performed by the CMS and ATLAS collaborations during the LHC Run 1 has been an important success. This document is a short review of the search for the Higgs boson performed by the CMS collaboration during the LHC Run 1 and Run 2. In the first part, after a brief description of the Higgs boson production and decay channels, the Run-1 results are presented emphasizing the possible hints of New Physics. The main part of this document is devoted to the search for the Higgs boson with the 13-TeV data collected by the CMS experiment in 2015 and 2016, including the Standard Model searches as well as the Beyond Standard Model searches, such as the search for additional Higgs bosons and for resonant and non-resonant double Higgs boson production.

New physics in multi-Higgs boson final states

We explore the potential for the discovery of the triple-Higgs signal in the decay channel at a 100 TeV hadron collider. We consider both the Standard Model and generic new-physics contributions, described by an effective Lagrangian that includes higher-dimensional operators. The selected subset of operators is motivated by composite-Higgs and Higgs-inflation models. In the Standard Model, we perform both a parton-level and a detector-level analysis. Although the parton-level results are encouraging, the detector-level results demonstrate that this mode is really challenging. However, sizable contributions from new effective operators can largely increase the cross section and/or modify the kinematics of the Higgs bosons in the final state. Taking into account the projected constraints from single and double Higgs-boson production, we propose benchmark points in the new physics models for the measurement of the triple-Higgs boson final state for future collider projects.

One-loop corrections to the Higgs self-couplings in the singlet extension

We investigate predictions on the triple Higgs boson couplings with radiative corrections in the model with an additional real singlet scalar field. In this model, the second physical scalar state (H) appears in addition to the Higgs boson (h) with the mass 125 GeV. The hhh vertex is calculated at the one-loop level, and its possible deviation from the predictions in the standard model is evaluated under various theoretical constraints. The decay rate of H→hh is also computed at the one-loop level. We also take into account the bound from the precise measurement of the W boson mass, which gives the upper limit on the mixing angle α between two physical Higgs bosons for a given value of the mass of H (mH). We find that the deviation in the hhh coupling from the prediction in the standard model can maximally be about 250%, 150% and 75% for mH=300, 500 and 1000 GeV, respectively, under the requirement that the cutoff scale of the model is higher than 3 TeV. We also discuss deviations from the standard model prediction in double Higgs boson production from the gluon fusion at the LHC using the one-loop corrected Higgs boson vertices.

Differential Higgs boson pair production at next-to-next-to-leading order in QCD

We report on the first fully differential calculation for double Higgs boson production through gluon fusion in hadron collisions up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. The calculation is performed in the heavy-top limit of the Standard Model, and in the phenomenological results we focus on pp collisions at 14 TeV. We present differential distributions through NNLO for various observables including the transverse-momentum and rapidity distributions of the two Higgs bosons. NNLO corrections are at the level of 10%-25% with respect to the next-to-leading order (NLO) prediction with a residual scale uncertainty of 5%-15% and an overall mild phase-space dependence. Only at NNLO the perturbative expansion starts to converge yielding overlapping scale uncertainty bands between NNLO and NLO in most of the phase-space. The calculation includes NLO predictions for pp -> HH+jet+X. Corrections to the corresponding distributions exceed 50% with a residual scale dependence of 20%-30%.

Single and double production of the Higgs boson at hadron and lepton colliders in minimal composite Higgs models

In the composite Higgs models, originally proposed by Georgi and Kaplan, the Higgs boson is a pseudo Nambu-Goldstone boson (pNGB) of spontaneous breaking of a global symmetry. In the minimal version of such models, global SO(5) symmetry is spontaneously broken to SO(4), and the pNGBs form an isospin doublet field, which corresponds to the Higgs doublet in the Standard Model (SM). Predicted coupling constants of the Higgs boson can in general deviate from the SM predictions, depending on the compositeness parameter. The deviation pattern is determined also by the detail of the matter sector. We comprehensively study how the model can be tested via measuring single and double production processes of the Higgs boson at LHC and future electron-positron colliders. The possibility to distinguish the matter sector among the minimal composite Higgs models is also discussed. In addition, we point out differences in the cross section of double Higgs boson production from the prediction in other new physics models.

Higgs boson production in the U(1)B−L model at the ILC

In the framework of the minimal [Formula: see text] extension of the Standard Model, we investigate the Higgs boson production processes [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] at the International Linear Collider (ILC). We present the production cross-sections, the relative corrections and compare our results with the expected experimental accuracies for Higgs decay channel [Formula: see text]. In the allowed parameter space, we find that the effects of the three single Higgs boson production processes might approach the observable threshold of the ILC. But the Higgs signal strengths [Formula: see text] of the two double Higgs boson production processes are all out of the observable threshold so that these effects will be difficult to be observed at the ILC.

Double Higgs boson production and decay in Randall-Sundrum model at hadron colliders

We investigate the double Higgs production and decay at the $14~ {\rm TeV}$ LHC and $33~ {\rm TeV}$ HE-LHC in both the standard model and Randall-Sundrum (RS) model. In our calculation we consider reasonably only the contribution of the lightest two Kaluza-Klein (KK) gravitons. We present the integrated cross sections and some kinematic distributions in both models. Our results show that the RS effect in the vicinities of $M_{HH} \sim M_{1}$, $M_{2}$ (the masses of the lightest two KK gravitons) or in the central Higgs rapidity region is quite significant, and can be extracted from the heavy SM background by imposing proper kinematic cuts on final particles. We also study the dependence of the cross section on the RS model parameters, the first KK graviton mass $M_1$ and the effective coupling $c_0$, and find that the RS effect is reduced obviously with the increment of $M_1$ or decrement of $c_0$.