Associate Higgs and gauge boson production at hadron colliders in a model with vector resonances

Motivated by new models of dynamical electroweak symmetry breaking that predict a light composite Higgs boson, we build an effective Lagrangian which describes the standard model (with a light Higgs) and vector resonances. We compute the cross section for the associate production of a Higgs and a gauge boson. For some values of model parameters we find that the cross section is significantly enhanced with respect to the standard model. This enhancement is similar at the LHC (large hadron collider) and the Tevatron for the same range of resonance mass. PACS 12.60.Nz     

Charged Higgs boson in the economical 3-3-1 model

The SU(3) _C ⊗ SU(3) _L ⊗ U(1) _X gauge model with two Higgs triplets (the economical 3-3-1 model) is presented. The minimal Higgs potential is considered in detail, and new Higgs bosons with the mass proportional to the bilepton mass are predicted. In the effective approximation, the charged Higgs bosons H ₂ ^± are scalar bileptons, while the neutral scalar bosons H ⁰ and H ₁ ⁰ do not carry a lepton number. The couplings of the charged Higgs bosons to leptons and quarks are given. We show that Yukawa couplings of H ₂ ^± to ordinary leptons and quarks are lepton-number violating. The pair production of H ₂ ^± at high-energy e ⁺ e ⁻ colliders with the polarization of the e ⁺, e ⁻ beams is studied in detail. A numerical evaluation shows that, if the Higgs mass is not too heavy, then the reaction can give an observable cross section in future colliders at a high degree of polarization. The reaction e ⁺ e ⁻ → H ₂ ^± W ^∓ is also examined. We show that the production cross sections of H ₂ ^± W ^∓ are very small, much below the pair production of H ₂ ^± , and, therefore, the associated production of H ₂ ^± and W ^∓ is, in general, not expected to lead to easily observable signals in the e ⁺ e ⁻ annihilation. The text was submitted by the authors in English.     

Production of a decoupled neutral gauge boson at the SSC

We consider an extension of the standard model with an extra neutral gauge bosonV which does not couple to the usual fermions or mix with the standardZ boson. A new fermion, which is either a color-triplet (Q) or a color-singlet (L), and a singlet Higgs scalar (X) are generic particles required for the extension group.V can be produced copiously by the process . We find 0760 0712 V 3 that there will be at least a few hundredV's produced at the SSC per year if the masses ofV andQ are less than 1 and 0.3 TeV respectively. Although the mixing of the standard and new Higgs scalars is small, the decay of the standard model Higgs scalar,H ₁2V, is comparable to the corresponding standard processes,H ₁2Z. A heavy standard model Higgs may open an important channel for the study of a new neutral gauge boson.     

Phenomenology of a second neutral gauge boson in the Drell-Yan process

We discuss the influence of a second neutral gauge boson to the Drell-Yan process. We find that for energies available in the near future and even at present energies, there are sizeable differences in the predictions of different models for the forward-backward asymmetry and the longitudinal polarization of the lepton.     

Testing two versions of lattice gauge theory: Creutz ratios inU(1)3

In our simplicial version of lattice gauge theory, we approximate Euclidean path integrals by tiling space-time with simplexes and by linearly interpolating the fields throughout each simplex from their values at the vertices. We compare this method with Wilson's lattice gauge theory forU(1) in three dimensions. As a standard of comparison, we compute the exact values of Creutz ratios of Wilson loops in the continuum theory. Monte Carlo computations using the simplicial method give Creutz ratios within a few percent of the exact values for reasonably sized loop atβ=1, 2, and 10. Similar computations using Wilson's method give ratios that typically differ from the exact values by factors of 2 or more for 1⩽β⩽3.5 and that have the wrongβ dependence. The better accuracy of the simplicial method is due to its use of the action and domain of integration of the exact theory, unaltered apart from the granularity of the simplicial lattice. We also present data on the action density and the mass gap. Research supported by the U.S. epartment of Energy under grant DE-FG04-84ER40166.     

Pseudo goldstones at future colliders from the extended BESS model

Decays and branching ratios of light neutralino production in $Z_R^0 \to \tilde \chi _i^0 \tilde \chi _j^0 $ in the left-right super-symmetric model are considered. We study in detail the signatures of one and two sided events in $Z_R^0 \to \tilde \chi _1^0 \tilde \chi _2^0 $ and $Z_R^0 \to \tilde \chi _2^0 \tilde \chi _2^0 $ respectively, and their dependence on the parameters of the light neutralino mixing matrix.     

Exotic decays of the 125 GeV Higgs boson at future e~+e~- colliders

The discovery of unexpected properties of the Higgs boson would offer an intriguing opportunity to shed light on some of the most profound puzzles in particle physics. Beyond Standard Model(BSM) decays of the Higgs boson could reveal new physics in a direct manner. Future electron-positron lepton colliders operating as Higgs factories, including CEPC, FCC-ee and ILC, with the advantages of a clean collider environment and large statistics,could greatly enhance sensitivity in searching for these BSM decays. In this work, we perform a general study of Higgs exotic decays at future e~+e~-lepton colliders, focusing on the Higgs decays with hadronic final states and/or missing energy, which are very challenging for the High-Luminosity program of the Large Hadron Collider(HL-LHC).We show that with simple selection cuts,O(10~(-3)-10~(-5)) limits on the Higgs exotic decay branching fractions can be achieved using the leptonic decaying spectator Z boson in the associated production mode e~+e~-→ZH. We further discuss the interplay between detector performance and Higgs exotic decays, and other possibilities of exotic decays.Our work is a first step in a comprehensive study of Higgs exotic decays at future lepton colliders, which is a key area of Higgs physics that deserves further investigation.     

Littlest Higgs模型中通过e^+e^-对撞研究新规范玻色子B_H与SM中规范玻色子的伴随产生过程

计划中的高能量、高亮度对撞机ILC在寻找新物理模型所预言的新的重粒子方面具有很大的潜力。本文,我们研究了在ILC上,通过过程e^+e^- ->r(Z)B_H发现littlest Higgs模型中最轻的新规范玻色子B_H的可能性。结果显示,在较大的参数空间范围,这两个过程都有较大的产生截面,能产生足够的信号探测B_H,尤其是对过程e^+e^- ->rB_H。另外,B_H的一些衰变道可以产生特征比较明显背景比较干净的信号。如果B_H存在,随着ILC的运行,新的规范玻色子B_H应能通过这两过程观测。     

Associated productions of the new gauge boson BH in the Littlest Higgs model with a SM gauge boson via e+e- collision

With the high energy and luminosity, the planned ILC has the considerable capability to probe the new heavy particles predicted by the new physics models. In this paper, we study the potential to discover the lightest new gauge boson BH of the Littlest Higgs model via the processes e+e- →γ(Z)BH at the ILC. The results show that the production rates of these two processes are large enough to detect BH in a wide range of the parameter spaces, specially for the process e+e- →γBH. Furthermore, there exist some decay modes for BH which can provide the typical signal and clean backgrounds. Therefore, the new gauge boson BH should be observable via these production processes with the running of the ILC if it exist.     

LHT model and Higgs boson production in association with a weak gauge boson at the LHC

Considering the process pp → VH+X(V = W or Z) is a significant channel for searching for a light Higgs boson,we calculate the contributions of the littlest Higgs model with T-parity(called LHT model) to its production cross section.We find that,in most of the parameter space,the value of the relative correction parameter R is very small.However,with reasonable values of the free parameters,its value can be significantly larger.     

具有T宇称的最小Higgs模型与LHC上Higgs波色子与弱规范波色子的联合产生

Considering the process pp→VH ＋X（V = W or Z） is a significant channel for searching for a light Higgs boson, we calculate the contributions of the littlest Higgs model with T-parity （called LHT model） to its production cross section. We find that, in most of the parameter space, the value of the relative correction parameter R is very small. However, with reasonable values of the free parameters, its value can be significantly larger.     

Associated production of a light Higgs boson and a chargino pair in the MSSM at linear colliders

In the minimal supersymmetric standard model (MSSM), we study the light Higgs boson radiation off a light-chargino pair in the process at linear colliders with GeV. We analyze cross sections in the regions of the MSSM parameter space where the process cannot proceed via on-shell production and subsequent decay of either heavier charginos or the pseudoscalar Higgs boson A. Cross sections up to a few fb are allowed, according to present experimental limits on the Higgs boson, chargino and sneutrino masses. We also show how a measurement of the production rate could provide a determination of the Higgs boson couplings to charginos.Received: 24 June 2004, Revised: 13 May 2005, Published online: 19 July 2005