Higgs Pair Research Articles

Sterile neutrinos, 0nu beta beta decay and the W-boson mass anomaly in a flipped SU(5) from F-theory

We investigate the low energy properties of an effective local model with flipped SU(5)times U(1)_{chi } gauge group, constructed within the framework of F-theory. Its origin is traced back to the SO(10) symmetry – associated with a geometric singularity of the compactification manifold – broken by an internal flux which is turned on along the seven-brane in the U(1)_{chi } direction. Topological properties and the choice of flux parameters determine the massless spectrum of the model to be that of the minimal flipped SU(5) supplemented with an extra right-handed electron-type state and its complex conjugate, E^c+{{bar{E}}}^c, as well as neutral singlet fields. The subsequent symmetry breaking to the SU(3)times SU(2)times U(1)_Y gauge group occurs with a Higgs pair in 10+{overline{10}} representations of SU(5). Next we proceed to the phenomenological analysis of the resulting effective model and the salient outcomes are: The E^c+{{bar{E}}}^c pair acquires a mass of few TeV and as such could solve the g_{mu }-2 discrepancy. Neutrino couplings to extra neutral singlets lead to an inverse seesaw mechanism where an extra light state could be a suitable dark matter candidate. The predictions of the model for the {0nu }beta beta decay rate could be tested in near future experiments. There are non-unitarity deviations from the lepton mixing matrix (U_{PMNS}), which could in principle explain the new precision measurement of the W-boson mass recently reported by the CDF II collaboration.

Machine learning the trilinear and light-quark Yukawa couplings from Higgs pair kinematic shapes

Revealing the Higgs pair production process is the next big challenge in high energy physics. In this work, we explore the use of interpretable machine learning and cooperative game theory for extraction of the trilinear Higgs self-coupling in Higgs pair production. In particular, we show how a topological decomposition of the gluon-gluon fusion Higgs pair production process can be used to simplify the machine learning analysis flow. Furthermore, we extend the analysis to include qoverline{q} → hh production, which is strongly suppressed in the Standard Model, to extract the trilinear Higgs coupling and to bound large deviations of the light-quark Yukawa couplings from the Standard Model values. The constraints on the rescaling of the trilinear Higgs self-coupling, κλ, and the rescaling of light-quark Yukawa couplings, κu and κd, at HL-LHC (FCC-hh) from single parameter fits are:κλ=0.531.70.971.03κu=−470430−5855κd=−360360−2628\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\displaystyle \\begin{array}{c}{\\kappa}_{\\lambda }=\\left[0.53,1.7\\right]\\ \\left(\\left[0.97,1.03\\right]\\right)\\\\ {}{\\kappa}_u=\\left[-470,430\\right]\\ \\left(\\left[-58,55\\right]\\right)\\\\ {}{\\kappa}_d=\\left[-360,360\\right]\\ \\left(\\left[-26,28\\right]\\right)\\end{array}} $$\\end{document}We show that the simultaneous modification of the Yukawa couplings can dilute the constraints on the trilinear coupling significantly. We perform similar analyses for FCC-hh. We discuss some motivated flavourful new physics scenarios where such an analysis prevails.

Quartic Gauge-Higgs couplings: constraints and future directions

Constraints on quartic interactions of the Higgs boson with gauge bosons have been obtained by the experimental LHC collaborations focussing on the so-called κ framework of flat rescalings of SM-like interactions in weak boson fusion (WBF) Higgs pair production. While such approaches are admissible to obtain a qualitative picture of consistency with the SM when the statistical yield is low, once more statistics become available a more theoretically consistent framework of limit setting is desirable. Reviewing the constraints provided at the Large Hadron Collider, we first show that these limits are robust when considered in a leading order context. Turning to radiative corrections, we demonstrate the limitations of this approach in the SM, and by adopting Higgs effective field theory techniques, we clarify the sensitivity from single Higgs measurements to rescalings of quartic Higgs-gauge couplings. We then discuss avenues for sensitivity improvements of WBF analyses employing Graph Neural Networks to combat the large contributing backgrounds.

Laser-assisted CP-odd and CP-even Higgs bosons production in THDM

In this paper, we have theoretically studied the neutral Higgs pair production in Two Higgs Doublet Model (THDM) in the presence of a circularly polarized laser field. The laser-assisted differential partial cross section is derived in the centre of mass frame at the leading order including Z diagram. The total cross section is computed numerically by integrating the differential cross section over the solid angle . Two benchmark points are discussed for the THDM parameters. In the first step, we have analysed the total cross section of by considering H 0 as the standard model (SM)-like Higgs boson. Then, the process is studied by taking h 0 as the Higgs boson of the SM. For both benchmark points, the laser-assisted total cross section of the studied processes depends on the produced neutral Higgs masses, the centre of mass energy and the laser field parameters. In addition, the maximum cross section occurs at high centre of mass energy for the process as compared to that of .

Benchmarking di-Higgs production in various extended Higgs sector models

We present a comprehensive study on Higgs pair production in various archetypical extended Higgs sectors such as the real and the complex 2-Higgs-Doublet Model, the 2-Higgs-Doublet Model augmented by a real singlet field and the Next-to-Minimal Supersymmetric extension of the Standard Model. We take into account all relevant theoretical and experimental constraints, in particular the experimental limits on non-resonant and resonant Higgs pair production. We present the allowed cross sections for Standard Model (SM)-like Higgs pair production and the ranges of the SM-like Yukawa and trilinear Higgs self-coupling that are still compatible with the applied constraints. Furthermore, we give results for the pair production of a SM-like with a non-SM-like Higgs boson and for the production of a pair of non-SM-like Higgs bosons. We find that di-Higgs production in the models under investigation can exceed the SM rate substantially, not only in the non-resonance region but also due to resonant enhancement. We give several benchmarks with interesting features such as large cross sections, the possibility to test CP violation, Higgs-to-Higgs cascade decays or di-Higgs production beating single Higgs production. In all of our benchmark points, the next-to-leading order QCD corrections are included in the large top-mass limit. For these points, we found that, depending on the model and the Higgs pair final state, the corrections increase the leading order cross section by a factor of 1.79 to 2.24. We also discuss the relation between the description of Higgs pair production in an effective field theory approach and in the specific models investigated here.

Two Higgs doublets, effective interactions and a strong first-order electroweak phase transition

It is well-known that type II two Higgs doublet models (2HDMs) can struggle to facilitate a strong first-order electroweak phase transition in the early universe whilst remaining theoretically appealing scenarios for many reasons. We analyse this apparent shortfall from the perspective of additional new physics. Starting from a consistent dimension-6 effective field theory Higgs potential extension, we identify the Higgs potential extensions that provide the necessary additional contributions required to achieve a strong first-order electroweak phase transition and trace their phenomenological implications for the Large Hadron Collider. In passing, we critically assess the reliability of the dimension-6 approximation depending on the expected 2HDM phenomenology. In particular, we focus on the role of Higgs pair production (resonant and non-resonant) and interference effects expected in top final states, which are the prime candidates of 2HDM exotics discoveries.

Enhanced Higgs pair production from higgsino decay at the HL-LHC

The scenario of multi-sector SUSY breaking predicts pseudo-goldstinos which are not absorbed by the gravitino and their mass can be as low as O(0.1) GeV. Since the interactions of pseudo-goldstinos are not so weak as gravitino, a produced higgsino can decay to a pseudo-goldstino plus a Higgs boson insider the detector at the LHC, and thus the higgsino pair production can lead to the signal of Higgs pair plus missing energy. For the scenario of natural SUSY which requires rather light higgsinos, such events may sizably outnumber the Higgs pair events predicted by the SM and be accessible at the HL-LHC (14 TeV with a luminosity of 3 ab−1). In this work we examine the observability of such Higgs pair plus missing energy from the decay of light higgsinos produced at the HL-LHC. Considering three channels of the Higgs-pair decay (bbWW⁎, bbγγ, bbbb), our detailed Monte Carlo simulations for the signal and backgrounds show that the best channel is bbbb+/ET, whose statistical significance can reach 2σ level for a light higgsino allowed by current experiments. This is over the SM Higgs pair result which is about 1.8σ.

The photon content of the proton in the CT18 global analysis

Recently, two photon PDF sets based on implementations of the LUX ansatz into the CT18 global analysis were released. In CT18lux, the photon PDF is calculated directly using the LUX master formula for all scales, \muμ. In an alternative realization, CT18qed, the photon PDF is initialized at the starting scale, \mu_0μ0, using the LUX formulation and evolved to higher scales \mu(>\mu_0)μ(>μ0) with a combined QED+QCD kernel at \mathcal{O}(\alpha),~\mathcal{O}(\alpha\alpha_s)𝒪(α),𝒪(ααs) and \mathcal{O}(\alpha^2)𝒪(α2). In the small-xx region, the photon PDF uncertainty is mainly induced by the quark and gluon PDFs, through the perturbative DIS structure functions. In comparison, the large-xx photon uncertainty comes from various low-energy, nonperturbative contributions, including variations of the inelastic structure functions in the resonance and continuum regions, higher-twist and target-mass corrections, and elastic electromagnetic form factors of the proton. We take the production of doubly-charged Higgs pairs, (H^{++}H^{--})(H++H−−), as an example of scenarios beyond the Standard Model to illustrate the phenomenological implications of these photon PDFs at the LHC.

Pair production of neutral Higgs particles in the B-LSSM

Higgs pair production provides a unique handle for measuring the strength of Higgs self interaction and constraining the shape of the Higgs potential. Including radiative corrections to the trilinear couplings of CP-even Higgs, we investigate the cross section of the lightest neutral Higgs pair production in gluon fusion at the Large Hadron Collider in the supersymmetric extensions of the standard model. Numerical results indicate that the correction to the cross section is about 11% in the B-LSSM, while is only about 4% in the MSSM. Considering the constraints of the experimental data of the lightest Higgs, we find that the gauge couplings of U(1) B–L and the ratio of the nonzero vacuum expectation values of two singlets also affect strongly the theoretical evaluations on the production cross section in the B-LSSM.

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.

Laser-assisted doubly charged Higgs pair production in Higgs triplet model (HTM)

In the framework of Higgs triplet model (HTM), we study the pair production process of doubly charged Higgs bosons via $e^{+}e^{-}$ annihilation in the presence of a laser field with circular polarization . We begin our work by presenting the theoretical calculation of the differential cross section in the centre of mass frame including both $Z$ and $\gamma$ diagrams. Then, from the numerical analysis of the production cross section's dependence on the laser field parameters, we have shown that the laser-assisted total cross section decreases as far as the electromagnetic field intensity enhances or by decreasing its frequency. Finally, we analyze the variation of the total cross section versus the mass of the doubly charged Higgs boson by fixing the laser field parameters and the centre of mass energy, and we have found that the order of magnitude of the cross section decreases as long as $M_{H^{\pm\pm}}$ increases.

Charged Higgs observability via charged Higgs pair production at future lepton collider

The observability of charged Higgs bosons \(H^{\pm }\) has been investigated at future lepton collider in type I two-Higgs- doublet model (2HDM) at the center of mass energy \(\sqrt{s}=1.5\) TeV. The signal process chain is \( e^{+}e^{-} \rightarrow Z^{*}/ \gamma ^{*}\rightarrow H^{+} H^{-}\rightarrow H W^{+} H W^{-}\rightarrow b {\overline{b}} j j b {\overline{b}} j j\). The process proceeds through virtual \( \gamma \) and Z boson exchange in the s channel. Several benchmark points are selected, and events are analyzed to reconstruct the mass of charged Higgs bosons \( H^{\pm } \). The value of \(\tan \beta \) is kept relatively high to enhance the branching ratio of \( H\rightarrow b{\overline{b}} \) to benefit the signal processes. The main standard model (SM) background process produced is \( t{\overline{t}} \). Signal selection and significance efficiencies are calculated at integrated luminosities of 100 fb\(^{-1} \) , 500 fb\(^{-1}\), 1000 fb\(^{-1} \), and 5000 fb\(^{-1} \). The reconstructed and corrected mass of charged Higgs bosons \( H^{\pm } \) is determined. Analyzing the results demonstrates that charged Higgs bosons can be discovered through the pair production process via its bosonic decays. This study is supposed to provide the experimentalists with a good way to examine the Higgs bosons beyond SM and to check the validity of 2HDM models in considered parameter space.

Twisted sheaves and $$\mathrm {SU}(r) / {\mathbb {Z}}_{r}$$ Vafa–Witten theory

The \(\mathrm {SU}(r)\) Vafa–Witten partition function, which virtually counts Higgs pairs on a projective surface S, was mathematically defined by Tanaka–Thomas. On the Langlands dual side, the first-named author recently introduced virtual counts of Higgs pairs on \(\mu _r\)-gerbes. In this paper, we instead use Yoshioka’s moduli spaces of twisted sheaves. Using Chern character twisted by rational B-field, we give a new mathematical definition of the \(\mathrm {SU}(r) / {\mathbb {Z}}_r\) Vafa-Witten partition function when r is prime. Our definition uses the period-index theorem of de Jong. S-duality, a concept from physics, predicts that the \(\mathrm {SU}(r)\) and \(\mathrm {SU}(r) / {\mathbb {Z}}_r\) partition functions are related by a modular transformation. We turn this into a mathematical conjecture, which we prove for all K3 surfaces and prime numbers r.

Laser-assisted charged Higgs pair production in Inert Higgs Doublet Model (IHDM)

The production of a pair of charged Higgs bosons from e+e− annihilation in the presence of a circularly polarized laser field is investigated in Inert Higgs doublet Model (IHDM) at e+e− colliders. We have derived the analytical expression for the laser-assisted differential cross section by using the Dirac-Volkov formalism at leading order including the Z and γ diagrams. Since the laser-free cross section of this process depends, in the lowest order, only on the mass of the charged Higgs boson and the energy of the center of mass, we have analyzed the dependence of the total laser-assisted cross section on these parameters and also on the laser parameters such as the number of photons exchanged, the laser field intensity and its frequency. The results found indicate that the electromagnetic field decreases the order of magnitude of the total cross section as much as the laser field intensity increases or by decreasing its frequency. Moreover, it becomes high for low charged Higgs masses and low center of mass energies.

Probing the triple Higgs boson coupling with machine learning at the LHC

Measuring the triple Higgs boson coupling is a crucial task in the LHC and future collider experiments. We apply the message passing neural network (MPNN) to the study of nonresonant Higgs pair production process $pp\ensuremath{\rightarrow}hh$ in the final state with $2b+2\ensuremath{\ell}+{E}_{\mathrm{T}}^{\mathrm{miss}}$ at the LHC. Although the MPNN can improve the signal significance, it is still challenging to observe such a process at the LHC. We find that a $2\ensuremath{\sigma}$ upper bound (including a 10% systematic uncertainty) on the production cross section of the Higgs pair is 3.7 times the predicted Standard Model cross section at the LHC with the luminosity of $3000\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, which will limit the triple Higgs boson coupling to the range of $[\ensuremath{-}3,11.5]$.

Composite Higgs revealed in Higgs pair photo-production at future colliders

The next generation electron-positron colliders are designed for precision studies of the Standard Model and its extensions, in particular in the Higgs sector. We consider the potential for discovery of composite Higgs models in Higgs pair production through photon collisions. This process is loop-generated, thus it provides access to all Higgs couplings and can show new physics effects in polarized and unpolarized cross-sections starting at relatively low collider energies. It is, therefore, relevant for all electron-positron colliders planned or in preparation. Sizeable deviations from the Standard Model predictions are present in a general class of composite Higgs models, as couplings of one or more Higgs bosons to fermions, or fermionic and scalar resonances, modify the destructive interference present in the Standard Model. In particular, large effects are due to the new quartic coupling of the Higgs to tops and to the presence of a light scalar resonance.

Searches for dark matter via charged Higgs pair production in the Inert Doublet Model at a γγ collider * *Supported by the National Natural Science Foundation of China (11205003, 11305001, 11575002, 11935001)

The Inert Doublet Model (IDM) is one of the simplest extensions beyond the Standard Model (SM) with an extended scalar sector, which provides a scalar dark matter particle candidate. In this study, we investigated the double charged Higgs production at a collider. By scanning the whole parameter space, we obtained the parameter points corresponding to the correct relic abundance of dark matter. After applying all theoretical and experimental constraints, the parameter space for the existence of dark matter was extremely restricted. We performed an analysis of the signal of production in the IDM and the SM background, with the optimized selection conditions chosen for the kinematic variables to maximize the signal significance. Comparing the signal with the background, we obtained the parameter points that may be detected in future collider experiments.

Studies of nonresonant Higgs pair production at electron-proton colliders

The measurement of the Higgs quartic coupling modifier between a Higgs boson pair and a vector boson pair, κ2V, is expected to be achieved from vector-boson fusion (VBF) production of a Higgs boson pair. However, this process involves another unmeasured parameter, the trilinear Higgs self-coupling modifier κλ. A sensitivity analysis should target both parameters. Since the LHC cannot avoid the gluon fusion pollution, which becomes severe for non-SM κλ, an electron-proton collider is more appropriate for the comprehensive measurement. In this regard, we study the VBF production of a Higgs boson pair in the bb¯bb¯ final state at the LHeC and FCC-he. Performing detailed analysis using simulated dataset, we devise the search strategy specialized at the LHeC and FCC-he and give a prediction for the sensitivity to both κ2V and κλ. We find that the two electron-proton colliders have high potential: the LHeC has similar exclusion prospects as the HL-LHC; the FCC-he is extremely efficient, excluding the parameter space outside κ2V∈[0.8,1.2] and κλ∈[1,2.5] at 95% C.L. for the total luminosity of 10 ab−1 and 10% uncertainty on the background yields.

Highly boosted Higgs bosons and unitarity in vector-boson fusion at future hadron colliders

We study the observability of new interactions which modify Higgs-pair production via vector-boson fusion processes at the LHC and at future proton-proton colliders. In an effective-Lagrangian approach, we explore in particular the effect of the operator {h}^2{W}_{mu nu}^a{W}^{a,mu nu} , which describes the interaction of the Higgs boson with transverse vector-boson polarization modes. By tagging highly boosted Higgs bosons in the final state, we determine projected bounds for the coefficient of this operator at the LHC and at a future 27 TeV or 100 TeV collider. Taking into account unitarity constraints, we estimate the new-physics discovery potential of Higgs pair production in this channel.

Searching for GeV-scale Majorana Dark Matter: inter spem et metum

We suggest a minimal model for GeV-scale Majorana Dark Matter (DM) coupled to the standard model lepton sector via a charged scalar singlet. We show that there is an anti-correlation between the spin-independent DM-Nucleus scattering cross section (σSI) and the DM relic density for parameters values allowed by various theoretical and experimental constraints. Moreover, we find that even when DM couplings are of order unity, σSI is below the current experimental bound but above the neutrino floor. Furthermore, we show that the considered model can be probed at high energy lepton colliders using e.g. the mono-Higgs production and same-sign charged Higgs pair production.