Comparison of the processes of Higgs boson pair production and associated production of a radion and a Higgs boson

It is demonstrated that a radion and a Higgs boson are similar up to the replacement of masses and coupling constants (m _r → m _h and Λ _r → v ₀) in the processes of their single production and the additional rescaling of the coupling constant at the cubic self-action of a Higgs boson \(\left( {1 \to 1 + \frac{{m_r^2 - m_h^2}}{{3m_h^2}}} \right)\) in the processes of their associated production.     

Role of h-->etaeta in intermediate-mass Higgs boson searches at the Large Hadron Collider

The dominance of the h-->etaeta decay mode for the intermediate-mass Higgs boson is highly motivated to solve the little hierarchy problem and to ease the tension with the precision data. However, the discovery modes for m(h) approximately <150 GeV, h-->gammagamma, and W/Zh-->(lnu/ll)(bb), will be substantially affected. In this Letter, we show that h-->etaeta-->4b is complementary and we can use this decay mode to detect the intermediate Higgs boson at the LHC, via Wh and Zh production. Requiring at least one charged lepton and 4B tags in the final state, we can identify a clean Higgs boson signal for m(h) approximately <150 GeV with a high significance and with a full Higgs mass reconstruction. We use the next-to-minimal supersymmetric standard model and the simplest little Higgs model for illustration.     

Six-fermion calculation of intermediate-mass Higgs boson production at future {e^+ e^-} colliders

The production of an intermediate-mass Higgs boson in processes of the kind fermions at the energies of future linear colliders is studied. The recently developed and fully automatic algorithm/code ALPHA is used to compute the tree-level scattering amplitudes for the reactions . The code has been interfaced with the Monte Carlo program HIGGSPV/WWGENPV, properly adapted to 6-fermion production, in order to provide realistic results, both in the form of cross sections and event samples at the partonic level. Phenomenological results, that incorporate the effects of initial-state radiation and beamstrahlung, are shown and commented, emphasizing the potentials of full six-fermion calculations for precise background evaluation as well as for detailed studies of the fundamental properties of the Higgs particle. Received: 22 May 1997 / Published online: 20 February 1998     

Processes of associated production of the Higgs boson with the Z boson in a superstrong magnetic field

We compute probabilities for the processes ee+Z+H, and e⁺+e^–Z+H in a superstrong magnetic field. It is shown that the magnetobremsstrahlung of the Higgs boson with the Z boson in the magnetic field Bs>B₀=m²/e=4.41·10¹³ G may be a relatively probable process, and that the superstrong magnetic field significantly influences the process e⁺+e^–Z+H, which is possible even in the absence of the field.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 104–108, January, 1991.The author thanks V. Ch. Zhukovskii and A. V. Borisov for discussions on the results of this work.     

Higgs boson production in two photon processes

We discuss some properties of the (instanton—anti-instanton) solution of the SU(2) gauge theory with a massless Higgs doublet recently found by Lipatov, Bukhvostov and Malkov.     

Higgs boson production and decay in little Higgs models with T-parity

We study Higgs boson production and decay in a certain class of little Higgs models with T-parity in which some T-parity partners of the Standard Model (SM) fermions gain their masses through Yukawa-type couplings. We find that the Higgs boson production cross section of a 120 GeV Higgs boson at the CERN LHC via gg fusion process at one-loop level could be reduced by about 45%, 35% and 20%, as compared to its SM prediction, for a relatively low new particle mass scale f=600, 700 and 1000 GeV, respectively. On the other hand, the weak boson fusion cross section is close to the SM value. Furthermore, the Higgs boson decay branching ratio into di-photon mode can be enhanced by about 35% in small Higgs mass region in certain case, for the total decay width of Higgs boson in the little Higgs model is always smaller than that in the SM.     

Double Higgs boson production in the models with isotriplets

The enhancement of double Higgs boson production in the extensions of the Standard Model with extra isotriplets is studied. It is found that in see-saw type II model decays of new heavy Higgs can contribute to the double Higgs production cross section as much as Standard Model channels. In Georgi–Machacek model the cross section can be much larger since the custodial symmetry is preserved and the strongest limitation on triplet parameters is removed.     

Higgs boson pair production via gluon fusion

We study pair production of Higgs bosons at hadron colliders via the gluon fusion process gg → HH. This process is dependent on the three-Higgs self-coupling. We find that this coupling is an important effect in determining the absolute size of the cross section. However, the shapes of the transverse momentum and the rapidity distributions are almost unaffected by its presence. At SSC energies we find cross sections in the range 1pb − 1fb, for Higgs boson masses of 50–250 GeV and top masses larger than 40 GeV. At LHC energies the cross sections are about a factor of five smaller.     

Pair production of Higgs boson in NMSSM at the LHC with the next-to-lightest C P-even Higgs boson being SM-like

The next-to-minimal supersymmetric standard model(NMSSM)more naturally accommodates a Higgs boson with a mass of approximately 125 Ge V than the minimal supersymmetric standard model(MSSM).In this work,we assume that the next-to-lightest CP-even Higgs boson h2 is the SM-like Higgs boson h,whereas the lightest CP-even Higgs boson h_(1)is dominantly singlet-like.We discuss the h_1h_1,h_2h_2,and h_1h_(2)pair production processes via gluon-gluon fusion at the LHC for an collision energy of 14 Te V,and we consider the cases in which one Higgsboson decays to bˉb and the other decays toγγorτ~+τ~-.We find that,for m_(h1) 62 GeV,the cross section of the gg→h_1h_(1)process is relatively large and maximally reaches 5400 fb,and the production rate of the h_1h_1→bˉbτ~+τ~-final state can reach 1500 fb,which make the detection of this final state possible for future searches of an integrated luminosity of 300 and 3000 fb~(-1).This is mainly due to the contributions from the resonant production process pp→h_2→h_1h_(1)and the relatively large branching ratio of h_1→bb and h_1→τ~+τ~-.The cross sections of the pp→h_2h_2and pp→h_1h_2 production processes maximally reach 28 fb and 133 fb,respectively.     

Vector boson decays of the Higgs boson

We derive the width of the Higgs boson into vector bosons. General formulas are derived both for the on–shell decay as well for the off–shell decays, and , where . For the off-shell decays the width of the decaying vector boson is properly included. The formulas are valid both for the Standard Model as well as for arbitrary extensions. As an example we study in detail the gauge-invariant effective Lagrangian models where we can have sizable enhancements over the Standard Model that could be observed at LEP. Received: 31 July 1998 / Revised version: 23 September 1998 / Published online: 6 November 1998     

Higgs boson production at hadron collidersin the kT-factorization approach

We consider the Higgs boson production at high energy hadron colliders in the framework of the k_T-factorization approach. The attention is focused on the dominant gluon-gluon fusion subprocess. We calculate the total cross section and transverse momentum distributions of the inclusive Higgs production using unintegrated gluon distributions in a proton obtained from the full CCFM evolution equation. We show that k_T-factorization gives a possibility to investigate the associated Higgs boson and jets production. We calculate the transverse momentum distributions and study the Higgs-jet and jet-jet azimuthal correlations in the Higgs + one or two jet production processes. We demonstrate the importance of the higher-order corrections within the k_T-factorization approach. These corrections should be developed and taken into account in the future applications. Received: 26 January 2005, Revised: 8 July 2005, Published online: 6 October 2005     

Soft gluon radiation in Higgs boson production at the LHC

We examine the contributions of soft gluons to the Higgs production cross section at the LHC in the Standard Model and its minimal supersymmetric extension. The soft gluon radiation effects of this reaction share many features with the Drell-Yan process, but arise at lowest order from a purely gluonic initial state. We provide an extension of the conventional soft gluon resummation formalism to include a new class of contributions which we argue to be universal, and resum these and the usual Sudakov effects to all orders. The effect of these new terms is striking: only if they are included, does the expansion of the resummed cross section to next-to-leading order reproduce the exact result to within a few percent for the full range of Higgs boson masses. We use our resummed cross section to derive next-to-next-to-leading order results, and their scale dependence. Moreover, we demonstrate the importance of including the novel contributions in the resummed Drell-Yan process.