Showing papers on "Higgs boson published in 1989"
TL;DR: In this article, the method of calculating radiative corrections to the scalar potentials is reviewed, with an emphasis on renormalization group improvement of the potential, and the results are then applied to the standard model to derive stringent bounds on Higgs and fermion passes.
850 citations
TL;DR: In this paper, the authors survey the low-energy phenomenological implications of superstring-inspired E 6 models and present experimental limits on these particles from both accelerator and non-accelerator data.
827 citations
TL;DR: An extension of the minimal model to include a singlet Higgs field whose vacuum expectation value determines the mixing is explored, and the possible production mechanisms and phenomenological signatures of the different Higgs bosons at these machines are analyzed.
Abstract: The minimal supersymmetric standard model contains two Higgs doublets which must mix via a mass parameter whose magnitude remains to be explained. We explore an extension of the minimal model to include a singlet Higgs field whose vacuum expectation value determines the mixing. We study the spectrum and couplings of Higgs bosons in this extended model and compare them with those in the minimal model. We examine a number of limiting cases analytically and also make numerical studies of the extended model both with and without constraints from the renormalization-group analysis of a parent superstring-inspired grand-unified-theory model. We establish the conditions for there to be a charged Higgs boson lighter than the ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and the circumstances under which there is no light neutral Higgs boson. With a particularly simple set of boundary conditions at the unification scale, the renormalization-group equations imply that one or more Higgs bosons are light enough to be found at the CERN LEP or SLAC Linear Collider and that many supersymmetric particles should be accessible to these accelerators and the Fermilab Tevatron; relatively few would require the Superconducting Super Collider, Large Hadron Collider, or a TeV-scale ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ collider for discovery. Finally, we analyze the possible production mechanisms and phenomenological signatures of the different Higgs bosons at these machines.
564 citations
CERN1
TL;DR: In this paper, a refined version of the flipped,SU(5)×U(1) string model with the following properties is presented: the complete massless spectrum is derived and shown to be free of all gauge and mixed anomalies apart from a single anomalous U(1).
433 citations
TL;DR: In this article, the Higgs sector of supersymmetric models with an additional SU(2)×U(1)Y singlet or an additional pair of Higgs doublet superfields is investigated.
Abstract: The Higgs sector of supersymmetric models with an additional SU(2)×U(1)Y singlet or an additional pair of Higgs doublet superfields is investigated. It is shown that in the model with a Higgs singlet bounds on Higgs boson masses are considerably weaker than in the minimal supersymmetric model; in particular, all neutral scalars can be heavier than about 150 GeV or lighter than $M_Z/\sqrt{2}$, whereas the mass of the charged Higgs boson is essentially unconstrained. The four doublet model resembles the minimal model more closely; in particular, the bounds for the heaviest and lightest neutral scalar and the heaviest charged Higgs boson are unaltered. In this model, many relations between masses of different Higgs bosons can be found; 44 of the 66 possible decays of one Higgs boson into another Higgs boson plus a real W or Z boson are kinematically forbidden. It is also shown that in both models, the lightest neutral scalar becomes indistinguishable from the standard model Higgs boson if all other Higgs bos...
386 citations
TL;DR: In this paper, the authors derived the rate for a B-meson to decay to a hadronic final state and a large mass electron-positron pair: B→X s e + e −.
292 citations
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TL;DR: The mass of the elementary particles is the central problem of modern physics, and is intimately connected with other fundamental problems such as the origin of CP violation, the mystery of the energy scales that determine the properties of the weak and gravitational interactions, the compositeness of particles, supersymmetry theory, and properties of not yet discovered Higgs bosons as mentioned in this paper.
Abstract: Mass is one of the most fundamental concepts of physics. Understanding and calculating the masses of the elementary particles is the central problem of modern physics, and is intimately connected with other fundamental problems such as the origin of CP violation, the mystery of the energy scales that determine the properties of the weak and gravitational interactions, the compositeness of particles, supersymmetry theory and the properties of the not‐yet‐discovered Higgs bosons.
241 citations
TL;DR: In this article, a search for light Higgs bosons has been performed in an electron beam-dump experiment and no positive signal is observed which allows us to reject at 90% CL the existence of a standard Higgs in the range from 1.2 to 52 MeV.
227 citations
TL;DR: In this article, a lower bound on the top quark mass of the Higgs boson was derived by numerically solving the renormalization group equations to two-loop order.
207 citations
TL;DR: A new lower bound on the {ital W}{sub {ital R}} mass, related to the strength of these lepton-lepton couplings, is derived as a result of the constraints obtained from low-energy experiments on a doubly charged Higgs doublet and a very light neutral Higgs triplet.
Abstract: In the context of minimal left-right-symmetric extensions of the standard $\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ model, four possible scenarios emerge depending upon the number of neutral Higgs fields that acquire nonzero vacuum expectation values. We examine these four scenarios in the case of a simple form for the scalar potential of the model. We find that by combining the minimization conditions appropriate to each of these scenarios with constraints coming from ${K}_{L}\ensuremath{-}{K}_{S}$ mixing and the absence of flavor-changing neutral currents, two of the scenarios are ruled out. For the allowed scenarios rather definitive consequences for the Higgs sector can be obtained. For instance, several of the scalar bosons are forced to be very heavy by flavor-changing neutral-current constraints. Aside from the Higgs boson which plays the role of the standard-model Higgs fields, the three left-handed triplet members are most likely to be light. Indeed, in one of the vacuum-expectation-value scenarios they are forced to be light (the neutral member being massless at the tree level). We catalogue the constraints from low-energy experiments on a doubly charged Higgs triplet and a very light neutral Higgs triplet, when these couple to two leptons (as in the left-right model). Many of the constraints we obtain are new. A new lower bound on the ${W}_{R}$ mass, related to the strength of these lepton-lepton couplings, is derived. The cross sections for these bosons are large out to masses of order several TeV and signatures for their decay are striking and essentially background-free.
178 citations
CERN1
TL;DR: In this article, the coupling of two gluons with two Z-bosons via a quark loop keeping the full dependence on the quark mass was studied and the results were used to study the production of Z-boomin pairs at hadron colliders both with and without the presence of a Higgs boson.
TL;DR: In this article, a fit to the baryon-octet mass spectrum to the first order of SU (3) breaking indicates unambiguously substantial sea-quark content in the Baryon at rest.
TL;DR: In this paper, Bogomol'nyi's method was used to find a static magnetic solution of the classical electroweak equations, which corresponds to a vacuum condensate of W and Z bosons.
CERN1
TL;DR: In this article, a simple N = 1 supersymmetric model is described, based on the group G=SU(4)×SU(2) L ×SU( 2) R.
TL;DR: It is shown that Higgs bosons which have an enhanced coupling to bottom quarks may be predominantly produced via bottom-quark fusion through the supersymmetric two-Higgs-doublet model.
Abstract: We study the production of Higgs bosons from heavy-quark fusion at future hadron colliders. We use a heavy-quark distribution function to combine the processes QQ\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}H and gQ\ensuremath{\rightarrow}HQ with the process gg\ensuremath{\rightarrow}QQ\ifmmode\bar\else\textasciimacron\fi{}H to obtain a cross section in which potentially large logarithms, of order ln(${m}_{H}$/${m}_{Q}$), are summed to all orders in the strong coupling. We show that Higgs bosons which have an enhanced coupling to bottom quarks may be predominantly produced via bottom-quark fusion. We concentrate on the supersymmetric two-Higgs-doublet model, in which this enhancement occurs naturally.
CERN1
TL;DR: In this article, the production of Z boson pairs at hadron colliders, produced by gluon fusion via an internal quark loop of arbitrary mass, both with and without the presence of a Higgs boson, was studied.
TL;DR: A renormalization-group-improved perturbative unitarity bound for elastic scattering amplitudes is proposed, which leads to upper bounds on the Higgs boson and top-quark masses as a function of the energy at which perturbation unitarity is violated and new physics enters.
Abstract: A renormalization-group-improved perturbative unitarity bound for elastic scattering amplitudes is proposed. This prescription leads to upper bounds on the Higgs boson and top-quark masses as a function of the energy at which perturbative unitarity is violated and new physics enters. Upper bounds on the scale of new physics in models with no Higgs boson are also discussed.
01 Jan 1989
TL;DR: In this paper, the authors discuss the explicit construction of a regularized, e.g. lattice, chiral gauge theory, with or without elementary Higgs fields, and argue that such a breaking can be compensated by adding all possible, renormalizable counterterms to the naive lattice action.
Abstract: We discuss the explicit construction of a regularized, e.g. lattice, chiral gauge theory, with or without elementary Higgs fields. In contrast with the vector-like case of QCD, the regularization breaks the chiral gauge invariance. We argue that such a breaking can be compensated by adding all possible, renormalizable counterterms to the naive lattice action. The requirement that the Green functions thus computed satisfy the Slavnov-Taylor identities of BRST symmetry determines the coefficients of the counterterms. We show how the procedure works in one-loop perturbation theory. The prospects for performing numerical simulations of chiral gauge theories are briefly discussed.
TL;DR: In this paper, it was shown that the lightest supersymmetric particle (LSP) is a nearly pure bino (partner of the hypercharge gauge boson) or a particular higgsino (symmetric or antisymmetric linear combination of the two neutral higgsinos with definite hypercharges).
TL;DR: In this paper, a simplified method was used to calculate high-energy unitarity constraints on SU(5)×U(1) superstring models, and then the renormalization group equations were used to evolve the constraints to the low-energy mass scale MW.
TL;DR: It is shown that there exists a process which may in certain models with multiple Higgs doublets generate a numerically acceptable asymmetry, which involves sphalerons and requires strong CP violation at temperatures larger than 1 TeV.
Abstract: The possibility is investigated that the baryon asymmetry of the Universe might have been created at the electroweak phase transition. It is shown that there exists a process which may in certain models with multiple Higgs doublets generate a numerically acceptable asymmetry. This process involves sphalerons and requires strong CP violation at temperatures larger than 1 TeV.
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TL;DR: A comprehensive review of the phenomenology of the conventional Higgs boson is presented in this paper, where the fundamentals of the standard model of electroweak interactions are reviewed and experimental limits on light Higgs Bosons are assessed and prospects for further experimental searches are evaluated.
Abstract: A comprehensive review of the phenomenology of the conventional Higgs boson is presented. The fundamentals of the standard model of electroweak interactions are reviewed. Experimental limits on light Higgs bosons are assessed and prospects for further experimental searches are evaluated.
TL;DR: In this paper, the area of the parameter space that gives rise to a massive, stable neutralino χ, with a cosmologically significant relic density, is described, and the effect of the lightest Higgs exchange on the elastic neutralino-nucleus cross section is shown.
TL;DR: In this article, the one-loop radiative corrections to vector-boson-vector-bosons scattering are calculated in the limit of high energy and even higher Higgs mass.
TL;DR: In this article, the authors considered the construction of a chiral, lattice Yukawa theory and found that to compensate for the chiral symmetry breaking introduced by the Wilson terms, one has to add three further counterterms to the naive lattice action.
TL;DR: In this article, the authors discuss the possibility of detecting an intermediate-mass Higgs boson in ultrarelativistic heavy-ion collisions at the LHC or the SSC.
TL;DR: It is demonstrated that the basic tree-level sum rules for Higgs-boson masses receive very small corrections even when the scale of the supersymmetry-breaking mass parameters describing the latter sector are very large.
Abstract: We compute the renormalization of the Higgs-boson masses of the minimal supersymmetric extension of the standard model as a function of the scale of mass breaking between gauge-Higgs bosons and their supersymmetric gaugino-Higgsino partners. We demonstrate that the basic tree-level sum rules for Higgs-boson masses receive very small corrections even when the scale of the supersymmetry-breaking mass parameters describing the latter sector are very large. We show analytically that the mass sum rules are screened against large effects from large mass splitting between the two sectors.
CERN1
TL;DR: In this paper, a phenomenological model based on a chiral lagrangian expansion to order s 2 for the scattering amplitudes of the longitudinally polarized W L and Z L gauge bosons in the case of a generic strongly interacting symmetry breaking sector is presented.
TL;DR: A screening theorem is proved that, as the Higgs-boson mass becomes large, the leading radiative corrections to any loop order are not measurable, thereby generalizing previous results of explicit calculations of one and two loops.
Abstract: We study the effects of a heavy Higgs boson on low-energy (<1 TeV) observables in the standard model. We prove a screening theorem that, as the Higgs-boson mass becomes large, the leading radiative corrections to any loop order are not measurable, thereby generalizing previous results of explicit calculations of one and two loops. More importantly, the reasons behind such an effect are identified and discussed in detail.
TL;DR: In this paper, the Weinberg-Salam sphalerons were discovered in the limit of vanishing mixing angle, and a set of saddle-point solutions for the Dashen-Hasslacher-Neveu Sphaleron was discovered.