The anomalous 3-boson couplings as an implication of the Higgs sector

We discuss the possible new electroweak interactions which may be generated by the Higgs sector at the scale of theZ mass. For this purpose, we give a set ofSU(2)×U(1) gauge invariant operators constructed in terms ofW, Z, γ and Higgs fields which in the unitary gauge describe all possible γWW andZWW anomalous couplings. The dimension of these operators varies from 6 to 12. This fact allows us to consider various scenaria for the manifestations of the New Physics. We conclude that the underlying dynamics induced by the Higgs sector can be tested through a model-independent amplitude analysis of gauge boson pair production at LEP2 and future colliders.     

Duality in the current propagator

The idea of local duality between generalized vector dominance and light cone algebra or parton model is applied to the propagator of vector currents. A set of sum rules reminiscent of the generalized first Weinberg sum rules but involving certain unknown parameters are derived. These parameters are fixed from the leptonic decay modes of ?, ω, ?. The sum rules are used to calculate the ω-? mixing angle and thereby predict $\text{Γ(?→}\text{K}\text{K}\text{) = 3.24±0.34}\text{MeV}$, in agreement with experiment. Simple mass mixing or current mixing model for the vector mesons seem to be inconsistent with data. The total cross section for e⁺e^?→hadrons is calculated in the scaling region. If scaling is achieved at $\text{s ? 9–16}\text{GeV}{}^2$ then it is argued that about 22% of the events in this energy region will include strange particles.     

Production of heavy resonances with electron and muon beams

The inelastic leptoproduction of heavy resonances J (J = J/ψ, Ψ,…) is investigated in a model where γ_vg → Jg is assumed to be the dominant mechanism. Analytic expressions for the differential cross section as well as for the helicity amplitudes are presented. A detailed numerical analysis of the angular distribution of the muon pair arising from the decay of the heavy resonance in its rest frame is presented.     

Helicity conservation in gauge boson scattering at high energy

We remark that the high energy gauge boson scattering processes involving two-body initial and final states satisfy certain selection rules described as helicity conservation of the gauge boson amplitudes (GBHC). These rules are valid at the Born level, as well as at the level of the leading and subleading 1-loop logarithmic corrections, in both the standard model and the minimal supersymmetric standard model (MSSM). A "fermionic equivalence" theorem is also proved, which suggests that GBHC is valid at all orders in the MSSM at sufficiently high energies, where the mass suppressed contributions are neglected.     

Asymptotic symmetry for the charmed and upsilon vector mesons

New duality is used to predict the leptonic width of the upsilon meson and derive a generalization of Yennie's relation assuming that is a Q$\text{Q}$ state of a new quark. Large symmetry breakings are found for processes D¹ → Dπ, D¹ → Dγ, F¹ → Fγ. The leptonic widths of some excited vector states are also calculated.     

Possible structures of the neutral current within a gauge theory framework

We examine a class of gauge theories based on U(1)×SU(2)×G allowing for an arbitrary number of gauge bosons, while retaining the lowq ² four fermion interaction of the standard model. Measurable consequences fore ⁺ e ^?→μ ⁺ μ ^? ande ⁺ e ^?→e ⁺ e ^? at presently available as well as LEP energies are presented. Implications of the recently determined QED cut-offΛ _? ? 100 GeV on gauge boson properties and the anomalous magnetic moment of the muon are pointed out.     

Convex relaxation for solving posynomial programs

Convex underestimation techniques for nonlinear functions are an essential part of global optimization. These techniques usually involve the addition of new variables and constraints. In the case of posynomial functions \({x_1^{\alpha _1 } x_2^{\alpha _2 }\ldots x_n^{\alpha _n } ,}\) logarithmic transformations (Maranas and Floudas, Comput. Chem. Eng. 21:351–370, 1997) are typically used. This study develops an effective method for finding a tight relaxation of a posynomial function by introducing variables y _j and positive parameters β _j , for all α _j > 0, such that \({y_j =x_j^{-\beta _j }}\) . By specifying β _j carefully, we can find a tighter underestimation than the current methods.     

The \gamma \gamma \to \gamma Z process at high energies and the search for virtual SUSY effects

We study the helicity amplitudes and the observables of the process at high energy. As in the case of the process studied before, the relevant diagrams in the standard model (SM) involve W, charged-quark, and lepton loops, while in SUSY we also have contributions from charginos and charged-sfermion or Higgs-loop diagrams. Above 250 GeV, the dominant SM amplitudes are themselves dominated by the W loop, and as for , they are helicity conserving and almost purely imaginary. We discuss the complementary information provided by for the identification of possible nonstandard effects. This process, together with , should provide very useful information on the nature of possible new physics particles, above the threshold of their direct production. Received: 26 April 1999 / Published online: 8 September 1999     

Baryon number non-conservation as a low-scale phenomenon

We analyse Baryon number non-conservation as a result of scalar boson mediated interactions characterised by a low mass scale (in the TeV region) in the framework of the standardSU(3)×SU(2)×U(1) gauge group.     

General description of new physics in t,b and boson interactions and its unitarity constraints

We list all possible dim = 6 CP conserving and SU(3) × SU(2) × U(1) gauge invariant interactions, which could be generated in case no new particles would be reachable in the future Colliders, and the only observable New Physics would be in the form of new interactions affecting the scalar sector and the quarks of the third family. These interactions are described by operators involving the standard model scalar field, the quarks of the third family and the gauge bosons. Subsequently, we identify those operators which do not contribute to LEP1 (and lower energy) observables at tree level and are not purely gluonic. Since present measurements do not strongly constrain the couplings of these operators, we derive here the unitarity bounds on them. Finally, in order to get a feeling on the possible physical meaning of the appearance of any of these operators, we identify the operators generated in a class of renormalizable dynamical models which at the TeV scale, are fully described by the SU(3) × SU(2) × U(1) gauge group.