Search

The effect of anomalous chromoelectric couplings of the gluon to the top quark are considered in e + e − →t t . The total cross section, as well as t and t polarizations are calculated to order α s in the presence of the anomalous couplings. One of the two linear combinations of t and t polarizations is CP even, while the other is CP odd. Limits that could be obtained at a future linear collider on CP-odd combinations of anomalous couplings are determined.

The data of recent single-tag two-photon experiments indicating noticeable excess in ( R γγ ) jet over fractionally charged quark-parton model-predictions is studied from the point of view of its implications on the gauge integer charge quark model. Focusing attention on the region of p T exceeding about 3 GeV, where higher order QCD and non-perturbative effects might be expected to be small, it is noted that this excess and its Q 2 dependence can be attributed to the presence of a colour component in the electromagnetic current provided the effective mass of the gluon lies between about 150 to 350 MeV. Accurate measurements of R γγ in the high p T region ( p T ⪆ 5 GeV ) are crucial for an unambiguous distinction between fcq and gauge-icq models.

Parity violating effects in PP → μ+μ−X and P P → μ + μ − X with the polarized targets have been calculated in the parton picture. The weak neutral currents used are based on an SU(2)L × SU(2)R × U(1) model. The result for the Weinbergy-Salam model occurs as a special case.

We have considered production of Higgs bosons in the process qq→qqWW→qqH and qq→qqZZ→qqZZ→qqH. It is shown that the contribution σ T of the transversely polarized intermediate vector bosons (V) in the equivalent vector boson approximation (EVBA) is comparable to the contribution σ L of the longitudinal ones. σ T can be as large as 1.5–2 times σ L . We also find that for interme diate values of m H , viz. 0.3–0.6 TeV, the leading EVBA for σ = σ L + σ T overestimates the exact total cross section by a factor, up to 2–3, even at high energies. σ T is negligible compared to the leading contribution σ L only for m H ⩾0.6 TeV, where the EVBA is correct within 15–20%.

It is shown that angular distribution in e+e−→γ+2 jets can serve as a possible test of quark charges but only above color threshold.