Energy dependence of e + e − → 6π and e + e − → N\bar N cross sections near N\bar N the threshold

Using recent BABAR, CMD-3 and SND data, the sum of e ⁺ e ^? → 3(π⁺π^?), 2(π⁺π^?π⁰), \(p\bar p\) , \(n\bar n\) cross sections is obtained. Unlike e ⁺ e ^? 3(π⁺π^?) and e ⁺ e ^? → 2(π⁺π^?π⁰) processes, no structures in total cross section are found near the \(N\bar N\) threshold within the limits of measurement errors.     

Determination of the CP properties of the Higgs boson from data on tau-lepton-decay products in the process e + e − → τ + τ − ν \bar \nu

The process e ⁺ e ^? → τ ⁺ τ ^? v $ \bar \nu $ , which is highly sensitive to anomalous Hττ interaction, is investigated within a model involving a new pseudoscalar Higgs boson. It is shown that the problem of separating the contributions of the scalar and pseudoscalar states of the Higgs boson can be solved via taking into account the polarizations of final-state particles. The inclusion of cascade tau-lepton decays makes it possible to determine reliably the CP state of the Higgs boson and to pinpoint the magnitude and sign of respective coupling constants.     

Study of the reactione + e −→K + K − in the energy range1350 \leqq \sqrt s \leqq 2400 MeV

Thee ⁺ e ^?→K ⁺ K ^? cross section has been measured from about 750 events in the energy interval \(1350 \leqq \sqrt s \leqq 2400 MeV\) with the DM2 detector at DCI. TheK ^± form factor |F _F ^±| cannot be explained by the ρ, ω, ? and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment.     

W+W−γ production in e+e− annihilation in the TeV region

The reaction e⁺e⁻→γW⁺W⁻ has been studied at TeV energies as a possible background to Higgs production. Our results differ significantly from previous estimates and show that the ratio signal/background can be kept reasonably large.     

Study of process e + e − → π+π−π0π0 at energies √s < 1 GeV with the spherical neutral detector

The cross section for the process e ⁺ e ^? → π⁺π^?π⁰π⁰ has been measured in an experiment with a spherical neutral detector, with the cross section at energies √s < 920 MeV having been measured for the first time. The model of vector dominance describes well the data obtained if the ρ, ρ′, and ρ″ resonances are taken into account. The probability of the decay ρ → π⁺π^?π⁰π⁰ is B(ρ → π⁺π^?π⁰π⁰) = (1.60 ± 0.74 ± 0.18) × 10^?5. The upper limit for the decay ω → π⁺π^?π⁰π⁰ has been improved by two orders of magnitude compared to previous measurements and is B(ω → π⁺π^?π⁰π⁰) < 2 × 10^?4 at a 90% confidence level.     

Effect of weak neutral currents in the process e− + p → e− + γ + X

Polarization effects in the inclusive process e^– + p e^– + + X due to the neutral current are studied in the framework of the Weinberg-Salam model. Expressions for the asymmetry parameters and the degree of circular polarization of the photons are obtained in the quark-parton picture. It is shown that measurement of such quantities gives additional information about the quark structure of the hadronic weak neutral current.Paper presented at the scientific session of the nuclear physics branch, USSR Academy of Sciences and the Moscow State University on Electromagnetic and Weak Interactions (Moscow, January 16–20, 1979).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 96–99, January, 1981.     

Search for the e + e − → K ± K S π ∓ process on the VEPP-2M e + e − collider

We report on the results of the search for the e ⁺ e ^? → K ^± K _S π ^? process. Data with an integrated luminosity of 1.36 pb^?1 collected in experiment with a spherical neutral detector (SND) on the VEPP-2M e ⁺ e ^? collider in the energy range from 1.36 to 1.38 GeV have been analyzed. The upper limits of the σ < 150 pb cross sections of the sought process have been established for an energy of 1.37 GeV at a confidence level of 90%.     

Proc ess es e+ e− → cccc and e+ e− → J/ψ + gg at $$\sqrt s = 10.59 G eV$$

Experimental data obtained by the BELLE Collaboration for inclusive J/ψ production in the processes e⁺e^? → J/ψ + gg and e⁺e^? → J/ψ + cc are discussed. These data are compared with the predictions of perturbative QCD that were obtained by two methods, that which employs information about the J/ψ wave function and that which relies on the hypothesis of quark-hadron duality exclusively. Both computational methods yield results that disagree with the experimental data considerably. The dependence of the cross section for the process e⁺e^? → J/ψ + gg on the effective gluon mass is studied. The cross section for the production of doubly charmed baryons Ξ _cc ^* is estimated.     

Loop corrections to the ϱ-parameter; the magnetic moment of the W± and e+e−→W+W−

Vector-boson loop corrections to the ϱ-parameter are considered for vector-boson self-interactions following from global SU(2)_WI broken by electromagnetism. Minimizing the degree of divergence of the ϱ-parameter restricts the free trilinear vector-boson self-couplings to a single one, the anomalous magnetic dipole moment, κ, of the W^+-. The analysis of e⁺e⁻ → W⁺W⁻ shows that this process is well suited for accurately determining this remaining free parameter, κ.     

Inclusive Production Λc in the e+e− - Annihilation

In the framework of the quark-diquark model of baryons, Λ_c can be considered as constituent c quark and ud diquark. In hadronizasion process baryon Λ_c can be produced from ud scalar diquark and c quark fragmentation. So in this work, in the lowest order of perturbative QCD, fragmentation functions c → Λ_c and ud → Λ_c are calculated and finally in the electron-positron annihilation in LEP, the inclusive cross section production of Λ_c is calculated about pole of z⁰.     

Comparative study of Z′ searches in e+e− and e−e− scattering

We consider indirect searches for additional neutral vector bosons in e⁺e⁻ and e⁻e⁻ collisions, and compare these two linear collider modes with similar analysis procedures and assumptions. Discovery limits and resolving power are discussed in a model-independent way.     

Radiative production of the lightest neutralino in e + e − annihilation

The production of the lightest stable neutralino in the process including general mixing of gauginos and Higgsinos is studied. General formulas for the differential cross section are presented. The dependence of the differential cross section on the photon energy spectrum and also the dependence of the total cross section on the beam energies for three different mixing scenarios are illustrated. The text was submitted by the author in English.     

Effects of the extra Z-boson in e+e−→W+W− reactions

We calculate the total and differential cross sections for the process e⁺e⁻→W⁺W⁻ including the effects of the extra Z-boson coming from the E₈⊗E₈ superstring. It is pointed out that the observation of the total and differential cross sections can determine the relative sign of the Weinberg angle τ_w and the mixing angle τ_e between Z^'₀ and Z _E.     

Jet masses in e+e− annihilation

We calculate heavy (M _H ² /s) and light (M _L ² /s) jet masses up toO(α _s ² ) in perturbative Quantum Chromodynamics (QCD). The sensitivity of these quantities to radiative corrections, quark masses, fragmentation effects as well as their infrared stability properties, are investigated and compared to those exhibited by other jet measures. A comparison with recent Mark II data is also presented.     

Deduction of the quantum numbers of low-lying states of the (e+e+e−e−) system from symmetry consideration

The features of the low-lying spectrum and the complete set of quantum numbers of each of the low-lying states of a (e⁺e⁺e⁻e⁻) system have been deduced based on symmetry.     

The process e + e − → ωπ0 near the Φ resonance

The reaction e ⁺ e ^?→ωπ⁰ near a Φ resonance was studied with a spherical neutral detector at VEPP-2M e ⁺ e ^? collider. Both main modes of decay of a ω meson were investigated: ω→π⁺π^?π⁰ and ω→π ⁰γ. The probability of decay Φ→ωπ⁰ was obtained from the magnitude of the interference wave in the cross section for the reaction e ⁺ e ^?→ωπ⁰→ π⁺π^?π⁰π⁰: B(Φ→ωπ⁰) = (5.5 _?1.4 ^+1.6 ±0.3) ×10^?5. The ratio of the partial widths of the ω meson was obtained from the ratio of the cross sections for the two modes: Γ(ω→π⁰γ )/Γ(ω→π⁺π^?π⁰) = 0.0994 ± 0.0036 ± 0.0038.