arXiv subjects

A. I. Titov

Publications and source records attributed to A. I. Titov.

43 records · Page 3Linked to original sources

arXiv2000

Production of ϕMesons in Near-Threshold πN and N N Reactions

We analyze the production of $ϕ$ mesons in $πN$ and NN reactions in the near-threshold region, using throughout the conventional ``non-strange'' dynamics based on such processes which are allowed by the non-ideal $ω-ϕ$ mixing. We show that the occurrence of the direct $ϕNN$ interaction may show up in different unpolarized and polarization observables in $πN\to Nϕ$ reactions. We find a strong non-trivial difference between observables in the reactions $pp\to ppϕ$ and $pn\to pnϕ$ caused by the different role of the spin singlet and triplet states in the entrance channel. A series of predictions for the experimental study of this effect is presented.

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arXiv1998

An isotopic effect in phi photoproduction at a few GeV

A distinct isotopic effect in phi photoproduction at 2-5 GeV region is identified by examining the production amplitudes due to Pomeron-exchange and meson-exchange mechanisms. This effect is mainly caused by the pi-eta interference constrained by SU(3) symmetry and the isotopic structure of the gamma NN coupling in the direct phi-radiation amplitude. It can be tested experimentally by measuring differences in the polarization observables between the gamma-p and gamma-n reactions.

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arXiv1998

The reaction NN \to NN ϕnear threshold

The sensitivity of polarization observables in the reaction $NN \to NN ϕ$ slightly above the threshold is studied with respect to the details of the one-boson exchange model and a possible admixture of hidden strangeness in the nucleon. It is shown that the finite-energy predictions differ strongly from the threshold predictions. A measurement of the beam - target asymmetry and the $ϕ$ decay anisotropy can help to disentangle the role of various reaction mechanisms.

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arXiv1997

Bremsstrahlung in intermediate-energy nucleon reactions within an effective one-boson exchange model

Within a covariant effective one-boson exchange model for the $T$ matrix of $NN$ interactions we present detailed calculations of bremsstrahlung cross sections for proton - proton and proton - neutron reactions at beam energies in the 1 GeV region. Besides pure bremsstrahlung processes we consider photons from $Δ$ decays and contributions from the $η\to γγ$ process. At beam energies above 700 MeV the $Δ$ decay channel dominates the spectra at large photon energies, where the interference between non-resonance processes and the $Δ$ decay channel becomes also important. Low energy photons stem from pure bremsstrahlung processes. The available experimental data at 730 MeV beam energy is well described. We extrapolate the model down to 280 MeV, where more detailed experimental data exist, and find agreement with angular distributions.

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arXiv1997

Polarization observables in the reaction $NN \to NN Φ$

We study the reaction $NN \to NN Φ$ slightly above the threshold within an extended one-boson exchange model which also accounts for $uud$ knock-out. It is shown that polarization observables, like the beam-target asymmetry, are sensible quantities for identifying a $s \bar s$ admixture in the nucleon wave function on the few per cent level.

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arXiv1996

Delta s density in a proton and unpolarized lepton - polarized proton scatterings

It is shown that the parity--violating deep--inelastic scatterings of unpolarized charged leptons on polarized protons, $\ell^{\mp} + \vec P\to \stackrel{\scriptscriptstyle(-)}{ν_{\ell}} + X$, could provide a sensitive test for the behavior and magnitude of the polarized strange--quark density in a proton. Below charm threshold these processes are also helpful to uniquely determine the magnitude of individual polarized parton distributions.

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arXiv1995

Decay Anisotropy of $e^+e^-$ Sources from $pN$ and $pd$ collisions

A full calculation of lepton-pair angular characteristics is carried out for $e^+e^-$ pairs created in $pp$, $pn$ and $pd$ collisions at intermediate energies. It is demonstrated that the proposed new observable, the dilepton decay anisotropy, quite sensitively changes for different sources and may be useful for their disentangling. The relevance of the dilepton decay anisotropy is shown in the context of a puzzling energy behavior for the ratio of the lepton yield from $pd$ to $pp$ reactions as observed at the BEVALAC.

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