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V. V. Gubin

Publications and source records attributed to V. V. Gubin.

11 recordsLinked to original sources
arXiv2001

Search for $a_0(980)$ and $f_0(980)$ mesons in $ϕ\toγK\bar K$

We study the decay $ϕ\toγK^+K^-$ taking into account the scalar mesons production $ϕ\toγ(f_0+a_0) \toγK^+K^-$ and the final state radiation. We note that the relative sign between the final state radiation amplitude and the scalar meson production amplitude is fixed in the $K^+K^-$ loop model which describes data on the $ϕ\to γf_0\toγππ$ and $ϕ\toγa_0\toγπη$ decays. As consequence this model predicts the definite interference between the final state radiation and the scalar resonance production amplitudes. We calculate the mass spectra of the $ϕ\toγK^+K^-$ decay and the differential cross-sections for $e^+e^-\toϕ\toγK^+K^-$ and for $e^+e^-\toϕ\toγK^0\bar K^0$ reactions.

hep-ph↗
arXiv2001

Analysis of the nature of the $ϕ\toγπη$ and $ϕ\toγπ^0π^0$ decays

We study interference patterns in the $ϕ\to(γa_0+π^0ρ)\toγπη$ and $ϕ\to(γf_0+π^0ρ)\toγπ^0π^0$ reactions. Taking into account the interference, we fit the experimental data and show that the background reaction does not distort the $π^0η$ spectrum in the decay $ϕ\toγπη$ everywhere over the energy region and does not distort the $π^0π^0$ spectrum in the decay $ϕ\toγπ^0π^0$ in the wide region of the $π^0π^0$ system invariant mass, $m_{ππ}>670$ MeV, or when the photon energy is less than 300 MeV. We discuss the details of the scalar meson production in the radiative decays and note that there are reasonable arguments in favor of the one-loop mechanism $ϕ\to K^+K^-\toγa_0$ and $ϕ\to K^+K^-\toγf_0$. We discuss also distinctions between the four-quark, molecular, and two-quark models and argue that the Novosibirsk data give evidence in favor of the four-quark nature of the scalar $a_0(980)$ and $f_0(980)$ mesons.

hep-ph↗
arXiv1998

Analysis of preliminary data on $e^+e^-\toϕ\toγf_0(980)\toγπ^0π^0$ reaction

We perform the analysis of the preliminary data on $e^+e^-\toϕ\toγf_0(980)\toγπ^0π^0$ reaction simultaneously with the data on $ππ$ scattering and reactions $J/ψ\toϕπ^+π^-$ and $K^-p\toπ^+π^-(Λ,Σ)$. It is found that the $f_0(980)$ meson mass $m_{f_0}=950$ MeV and $B(ϕ\toγf_0\toγπ^0π^0)\simeq1\cdot10^{-4}$.

hep-ph↗
arXiv1997

Search for the scalar a_0 and f_0 mesons in the ϕradiative decays

The potentialities of the production of the $a_0$ and $f_0$ mesons in the $ϕ$ radiative decays are considered based on a new two-channel analysis of the $ππ$ scattering in a energy region near 1 GeV. We predict $BR(ϕ\toγf_0(980))\sim10^{-5}-10^{-4}$ that is a great value for the decay forbidden by the Okubo-Zweig-Iizuka rule. We discuss the four-quark, $K\bar K$-molecule and two-quark scenarios for the $a_0$ and $f_0$ mesons. It is presented arguments that the $e^+e^-$-colliders and especially the $ϕ$ factories give the possibility to choose a single one out of them.

hep-ph↗
arXiv1997

Search for the scalar $a_0$ and $f_0$ mesons in the reactions $e^+e^-\toγπ^0π^0(η)$

It is shown that the reactions $e^+e^-\toγπ^0π^0(η)$ give a good chance for observing scalar $a_0$ and $f_0$ mesons. In the photon energy region less then 100 MeV the vector meson contributions $e^+e^-\to V^0\toπ^0 V'^0\toγπ^0π^0(η)$ are negligible in comparison with the scalar mesons $e^+e^-\toϕ\toγf_0(a_0)\toγπ^0π^0(η)$ for $BR(ϕ\toγf_0(a_0)\toγπ^0π^0(η))$ greater than $5\cdot10^{-6}(10^{-5})$. Using two-channel treatment of the $ππ$ scattering the predictions for $BR(ϕ\toγ(f_0+σ)\toγππ)$ are derived. The four quark model, the model of $K\bar K$ molecule and the$s\bar s$ model of scalar $f_0$ and $a_0$ mesons are discussed.

hep-ph↗
arXiv1997

Interference in the reaction $e^+e^-\toγπ^+π^-$ and the final state interaction

We describe the interference between amplitudes $e^ + e^-\toρ\toγπ^+π^-$ and $e^ + e^-\toϕ\toγ(f_0 + σ) \toγπ^ + π^-$, with regard to the phase of the elastic $ππ$ scattering background and mixing of the $f_0$ and $σ$ mesons. It is shown that the Fermi-Watson theorem for the final state interaction in the reaction $e^ + e^-\toρ\toγπ^ + π^-$ is not valid in the case of soft photons, $ω< 100$ MeV, in the $ϕ$ meson region. The interference patterns in the spectrum of the photon energy differential cross-section and in the full cross-section as a function of the beam energy are obtained.

hep-ph↗
arXiv1996

The interference in the reaction $e^+e^-\toγπ^+π^-$ and the search for the decay $ϕ\toγf_0\toγπ^+π^-$

We describe the interference between amplitudes $e^+e^- \to ρ\to γπ^+π^-$ and $e^+e^- \to ϕ\to γf_0 \to γπ^+π^-$, where $f_0$ meson is considered in the frameworks of the four-quark model and the model of the scalar $K\bar K$ molecule. The general expressions for the differential cross section with the radiative corrections and two angle cuts are given. The interference patterns are obtained in the spectrum of the differential cross section by the energy of the photon and in the full cross section by the energy of the beams.

hep-ph↗
arXiv1996

Production of scalar $K\bar K$ molecules in $ϕ$ radiative decays

The potentialities of the production of the scalar $K\bar K$ molecules in the $ϕ$ radiative decays are considered beyond the narrow resonance width approximation. It is shown that $BR(ϕ\rightarrowγf_0(a_0)\rightarrowγππ(πη))\approx (1÷2)\times 10^{-5}\ ,\BR(ϕ\rightarrowγ(f_0+a_0)\rightarrowγK^+K^-)\alt 10^{-6}$ and $BR(ϕ\rightarrowγ(f_0+a_0) \to γK^0\bar K^0)\alt 10^{-8}$. The mass spectra in the $ππ ,\ πη ,\ K^+K^-\ ,\ K^0\bar K^0$ channels are calculated. The imaginary part of the amplitude $ϕ\rightarrowγf_0(a_0)$ is calculated analytically. It is obtained the phase of the scalar resonance production amplitude that causes the interference patterns in the reaction $e^+e^-\rightarrowγπ^+π^-$ in the $ϕ$ meson mass region.

hep-ph↗