Production of Weak Bosons and Higgs Bosons at e-e- Colliders

We present calculations of cross sections for single $W^-$ and $Z$ production and $W^-W^-, W^-Z, W^-\gamma, ZZ$, and $W^+W^-$ pair production within the Standard Model at $e^-e^-$ linear colliders. We evaluate Standard-Model Higgs boson production in the channels $e^-e^- \to e^-e^- H$, $e^-\nu W^- H$, and $e^-e^- ZH$. We also illustrate the enhancements in the $W^-W^-$ cross section that would result from a strongly-interacting Higgs sector or from a $H^{--}$ resonance in a Higgs doublet + triplet model.Comment: Standard Latex, 19 pages of text. 11 postscript figures included; hardcopies by fax or mail available upon request. MAD/PH/77

Strong WW Scattering at Photon Linear Colliders

We investigate the possibility of observing strong interactions of longitudinally polarized weak vector bosons in the process $\gamma \gamma \to ZZ$ at a photon linear collider. We make use of polarization of the photon beams and cuts on the decay products of the $Z$ bosons to enhance the signal relative to the background of transversely polarized $ZZ$ pairs. We find that the background overwhelms the signal unless there are strong resonant effects, as for instance from a technicolor analogue of the hadronic $f_2(1270)$ meson.Comment: 13 pages including 6 figures (uuencoded), some rewording to the text, LBL-35746, MAD/PH/83

The Indirect Limit on the Standard Model Higgs Boson Mass from the Precision FERMILAB, LEP and SLD Data

Standard Model fits are performed on the most recent leptonic and b quark Z decay data from LEP and SLD, and FERMILAB data on top quark production, to obtain $m_t$ and $m_H$. Poor fits are obtained, with confidence levels $\simeq$ 2%. Removing the b quark data improves markedly the quality of the fits and reduces the 95% CL upper limit on $m_H$ by $\simeq$ 50 GeV.Comment: 6 pages 3 tables i figur

Multiple WLW_L Production from Inelastic WLWLW_L W_L Scattering at s^≫MH\sqrt{\hat{s}} \gg M_H

We explore the inelastic production of multiple longitudinal weak bosons as a manifestation of a strongly interacting symmetry breaking sector. By analogy with QCD, final states with large multiplicities are expected to occur not far above the energy scale of the lowest resonances of the underlying strong theory. We consider the feasibility of observing such phenomena in the environment of a very high energy hadron collider.Comment: 23 pages, Latex, 4 figures in separate postscript file, UCLA Report 92/TEP/4

What Precision Electroweak Physics Says About the SU(6)/Sp(6) Little Higgs

We study precision electroweak constraints on the close cousin of the Littlest Higgs, the SU(6)/Sp(6) model. We identify a near-oblique limit in which the heavy W' and B' decouple from the light fermions, and then calculate oblique corrections, including one-loop contributions from the extended top sector and the two Higgs doublets. We find regions of parameter space that give acceptably small precision electroweak corrections and only mild fine tuning in the Higgs potential, and also find that the mass of the lightest Higgs boson is relatively unconstrained by precision electroweak data. The fermions from the extended top sector can be as light as 1 TeV, and the W' can be as light as 1.8 TeV. We include an independent breaking scale for the B', which can still have a mass as low as a few hundred GeV.Comment: 52 pages, 16 figure

Hadron Collider Signatures for New Interactions of Top and Bottom Quarks

One of the main goals for hadron colliders is the study of the properties of the third generation quarks. We study the signatures for new TeV resonances that couple to top or bottom quarks both at the Tevatron Run II and at the LHC. We find that in the simplest production processes of Drell-Yan type at the Tevatron, the signals are overwhelmed by QCD backgrounds. We also find that it is possible to study these resonances when they are produced in association with a pair of heavy quarks or in association with a single top at the LHC.In particular, with an integrated luminosity of 300 fb$^{-1}$ at the LHC, it is possible to probe resonance masses up to around 2 TeV.Comment: 24 pages, 15 figures, Minor corrections, version to appear in Phys. Rev.

Unitary Standard Model from Spontaneous Dimensional Reduction and Weak Boson Scattering at the LHC

Spontaneous dimensional reduction (SDR) is a striking phenomenon predicted by a number of quantum gravity approaches which all indicate that the spacetime dimensions get reduced at high energies. In this work, we formulate an effective theory of electroweak interactions based upon the standard model, incorporating the spontaneous reduction of space-dimensions at TeV scale. The electroweak gauge symmetry is nonlinearly realized with or without a Higgs boson. We demonstrate that the SDR ensures good high energy behavior and predicts unitary weak boson scattering. For a light Higgs boson of mass 125GeV, the TeV-scale SDR gives a natural solution to the hierarchy problem. Such a light Higgs boson can have induced anomalous gauge couplings from the TeV-scale SDR. We find that the corresponding WW scattering cross sections become unitary at TeV scale, but exhibit different behaviors from that of the 4d standard model. These can be discriminated by the WW scattering experiments at the LHC.Comment: 38pp, Eur.Phys.J.(in Press); extended discussions for testing non-SM Higgs boson(125GeV) via WW scattering; minor clarifications added; references added; a concise companion is given in the short PLB letter arXiv:1301.457

Coulomb Phase Gluon Scattering at Strong Coupling

We calculate corrections to gluon scattering amplitudes in a Coulomb phase using gauge/string duality. The Coulomb phase considered is a maximal rank breaking of $SU(n_1+n_2)\to SU(n_1)\times SU(n_2) \times U(1)$. This problem therefore has 3 scales involved: 1) the scale of the massive fields $M_W$ arising from the spontaneous breaking of the gauge group; 2) The scale of the scattering, characterized by the Mandelstam variables $s,t,u$; 3) The IR regulator $m_{IR}$. We find corrections in the hard scattering limit $|s|,|t|,|u|\gg m_{IR}^2 \gg M_W^2$, and also find below threshold corrections with $M_W^2 \gg |s|,|t|,|u|$. We find that the corrections in the second case are finite, and so are IR regulator independent.Comment: 17+17 pages, 3 figure

Minimal Z' models: present bounds and early LHC reach

We consider `minimal' Z' models, whose phenomenology is controlled by only three parameters beyond the Standard Model ones: the Z' mass and two effective coupling constants. They encompass many popular models motivated by grand unification, as well as many arising in other theoretical contexts. This parameterization takes also into account both mass and kinetic mixing effects, which we show to be sizable in some cases. After discussing the interplay between the bounds from electroweak precision tests and recent direct searches at the Tevatron, we extend our analysis to estimate the early LHC discovery potential. We consider a center-of-mass energy from 7 towards 10 TeV and an integrated luminosity from 50 to several hundred pb^-1, taking all existing bounds into account. We find that the LHC will start exploring virgin land in parameter space for M_Z' around 700 GeV, with lower masses still excluded by the Tevatron and higher masses still excluded by electroweak precision tests. Increasing the energy up to 10 TeV, the LHC will start probing a wider range of Z' masses and couplings, although several hundred pb^-1 will be needed to explore the regions of couplings favored by grand unification and to overcome the Tevatron bounds in the mass region around 250 GeV.Comment: 25 pages. v2: small improvements and minor corrections, version accepted for publication on JHE

Vector boson Pair Production at Supercolliders; useful approximate helicity amplitudes

We study vector boson pair production at $LHC$ and $SSC$, taking into account the effects generated by the anomalous vector boson and Higgs couplings induced by the operators ${\cal O}_W$ and ${\cal O}_{UW}$, which are the only dim=6 operators preserving $SU(2)_c$. These operators lead to enhanced production of transverse vector bosons, as opposed to the enhanced production of longitudinal gauge bosons, induced in case M_H\gsim 1\ TeV, by dim=4 terms already existing in the Standard Model lagrangian. For vector boson pair masses larger than $1\ TeV$, we establish very simple approximate expressions for the standard as well as the non-standard helicity amplitudes for $q\bar q$ annihilation and vector boson fusion, which accurately describe the physics. These expressions should simplify the experimental search for such interactions. We finally discuss the observability and the disentangling of these interactions.Comment: 22 pages, 6 figures avaible by air mail upon request , (e-mail [email protected] PM/93-26 THES-TP 93/