G. J. Gounaris

Signatures of the anomalous

The possible form of New Physics (NP) interactions affecting the ZZZ, ZZγ and Zγγ vertices, is critically examined. Their signatures and the possibilities to study them, through ZZ and Zγ production, at the e e + Colliders LEP and LC and at the hadronic Colliders Tevatron and LHC, are investigated. Experimental limits obtained or expected on each coupling are collected. A simple theoretical model based on virtual effects due to some heavy fermions is used for acquiring some guidance on the plausible forms of these NP vertices. In such a case specific relations among the various neutral couplings are predicted, which can be experimentally tested and possibly used to constrain the form of the responsible NP structure.

Z_{\gamma}

Abstract A conservative expansion of the Weinberg-Salam (WS) model to the group SU(2) × U(1) × G increases the structure of neutral currents in the PETRA/PEP/LEP range, while preserving all testable WS predictions at low energies. The special case of SU(2) × U(1) × Ũ(1) is treated in detail.

and

AbstracAn effective Lagrangian framework for studying narrow glueballs is further developed, in which the glueball propagator is calculated in terms of its Bethe-Salpeter (BS) wave function. For a 0−+ glueball in thei(1440) mass region, physically motivated assumptions for its BS function predict its decay rate in agreement with thei(1440) width. The propagator of a 0++ glueball always has space-like poles. If a 0++ glueball exists, it cannot be narrow.

Z Z

Abstract Non-zero values of appropriately defined observables related to the spin-polarization (i.e. to the angular distribution of the decay products) of the W + and the W − produced in e + e − annihilation constitute unambiguous signals for the presence of CP violation in the interactions responsible for the process e + e − → W + W − .

production at the lepton and hadron colliders

Abstract Data on μ pair production in the presently accessible e + e − energy range put nontrivial restrictions on low mass weak gauge boson properties.

Possible structures of neutral currents at PETRA/PEP and LEP

A simple treatment of the dominant radiative corrections to theW± andZ0 mass formulae due to fermion-loop corrections to the propagator is given, including the possibility of a very massive top quark,mt>Mw. A thorough comparison with the results of the complete (SU(2)L×U(1)Y) one-loop calculations is presented. Using α,Gμ andMz as input, we find excellent agreement with the complete one-loop calculations (withmHIGGS≃100GeV) for all values ofmt within an expected error ofΔMW≅(α/2πMW≅100MeV) inMW andΔsW2≅0.002 in the weak angle,sw2. Technically we differ from previous work in diagonalizing the γZ propagator for arbitrary values ofq2, thus allowing for extensive use of the notion of “running” coupling constants and masses. We also give a simple and closed formula for the radiative corrections to be applied tosw2 (accurate within an expected error ofΔsw2≅0.002), when extractingsW2≅0.002), when extractingsW2 from neutrino scattering experiments. As a strategy for future precision tests of the electroweak theory, we suggest attempting to isolate and to test directly the “new physics” of boson loops and other new phenomena by comparing with and looking for deviations (larger thanΔMW≅(α/2π)Mw) from the predictions of the dominant fermion-loop calculation.

THE ZERO-SPIN GLUEBALLS - A NEW APPROACH TO RELATIVISTIC BOUND-STATES

We compute the helicity amplitudes for bosonboson scattering at high energy due to the operatorsOBΦ,OWΦ andOUB, and we derive the corresponding unitarity bounds. Thus, we provide relations between the couplings of these operators and the corresponding New Physics thresholds, where either unitarity is saturated or new degrees of freedom are excited. We compare the results with those previously obtained for the operatorsOW andOUW and we discuss their implications for direct and indirect tests at present and future colliders. The present treatment completes the study of the unitarity constraints for all blind bosonic operators.

Genuine tests of CP invariance in e+e− → W+W−☆

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 lowq2 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.

Restrictions on possible early weak gauge boson from petra QED cut-off

Abstract We consider the strength of the γ W 0 transition, λ W , within the framework of asymptotic freedom sum rules, incorporating the recent experimental results on the intermediate vector bosons. A consistent picture emerges, combining Λ H ⪞G −1 2 F , an excited boson between 0.3 TeV and 0.8 TeV and λ 2 W = sin 2 Θ W .

The radiative corrections to the electroweak parameters in the dominant fermion-loop approximation

The decay width of the lowest pseudoscalar glueball is calculated as a function of its mass, using an effective interaction for the glueball field with the gluons, and assuming that this glueball state is so narrow that a perturbative treatment makes sense. The glueball Bethe-Salpeter wave functions, which defines this interaction, is assumed to be determined by asingle scale, so that simple parametrizations are adequate. The glueball propagator and its decay rate to quarks is thus calculated. The result for a pseudoscalar glueball in the 1440 MeV region agrees with the experimental width of the i-state.