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D. A. Bukin

Publications and source records attributed to D. A. Bukin.

At least 37 records · Page 2Linked to original sources
arXiv2001

Review of experimental results from SND detector

The review of experimental results obtained with SND detector at VEPP-2M $e^+e^-$ collider in the energy region $\sqrt[]{s}=0.36$ -- 1.38 GeV is given. The presented results include the following items: studies of the light vector mesons radiative decays, OZI-rule and G-parity suppressed $ϕ$-meson rare decays, $ϕ$-meson parameters measurements, studies of $e^+e^-\toπ^+π^-π^0$ process dynamics, $η$ and $K_S$ mesons rare decays, $η$ and $ϕ$ mesons conversion decays, and study of the $e^+e^-$ annihilation into hadrons.

hep-ex↗
arXiv2001

Study of the $ππ$ mass spectra in the process $e^+e^- \to π^+π^-π^0$ at $\sqrt[]{s} \simeq 1020$ MeV

The invariant mass spectra of the $π^+π^-$ and $π^\pmπ^0$ pairs in the process $e^+e^- \to π^+π^-π^0$ were studied in the SND experiment at the VEPP-2M collider in the energy region $\sqrt[]{s} \simeq 1020$ MeV. These studies were based on about $0.5 \times 10^6$ experimental events. The spectra were analyzed in the framework of the vector meson dominance model. It was found that the experimental data can be described with $e^+e^- \to ρπ\to π^+π^-π^0$ transition only. Upper limit on the branching ratio of the $ϕ(1020)\toπ^+π^-π^0$ decay through intermediate states different from $ρπ$ was obtained at the 90 % confidence level: $B(ϕ\toπ^+π^-π^0)<6 \cdot 10^{-4}$. The $ρ$-meson mass and width which follow from the spectra analysis are $m_ρ=775.0\pm 1.3$ MeV, $Γ_ρ=150.4 \pm 3.0$ MeV. Neutral and charged $ρ$-mesons mass difference was found to equal $m_{ρ^\pm}-m_{ρ^0}=-1.3\pm2.3$ MeV. In the $π^+π^-$ mass spectrum the $ρ-ω$ interference was seen at two standard deviations level.

hep-ex↗
arXiv2001

SND Upgade

The program of upgrade of the Spherical Neutral Detector for future experiments at a new VEPP-2000 $e^+e^-$ collider is presented. Modernization includes upgrades of electromagnetic calorimeter, tracking system, detector electronics, data acquisition system, and offline software. It is also planned to equip the detector with two new subsystems: particle identification system based on aerogel Cherenkov counters and external electron tagging system for $γγ$ physics.

hep-ex↗
arXiv2001

Measurements of the parameters of the $ϕ(1020)$ resonance through studies of the processes $e^+e^- \to K^+K^-$, $K_SK_L$ and $π^+π^-π^0$

The cross sections of the processes $e^+e^- \to K^+K^-$, $e^+e^- \to K_SK_L$ and $e^+e^- \to π^+π^-π^0$ were measured in the SND experiment at the VEPP-2M collider in the energy region near the $ϕ(1020)$ meson. These measurements were based on about $10^6$ $K^+K^-$, $0.5 \times 10^6$ $K_SK_L$ and $0.4 \times 10^6$ $π^+π^-π^0$ selected events. Themeasured cross sections have been analyzed in the framework of the vector meson dominance model and the main parameters of the $ϕ$-resonance were obtained, such as its mass, width, the production cross section and branching ratios of the main decay modes. The measured value of the $ϕ$ meson total width, $Γ_ϕ = 4.21 \pm 0.04$ is lower than the present world average of $4.458 \pm 0.032$ MeV. Contributions in addition to the conventional vector meson dominance model were found in the $e^+e^- \to π^+π^-π^0$ reaction cross section.

hep-ex↗
arXiv2001

Direct measurement of the phi(1020) leptonic branching ratio

The process e+e-->mu+mu- has been studied by SND detector at VEPP-2M e+e- collider in the phi(1020)-resonance energy region. The measured effective phi meson leptonic branching ratio: B(phi->l+l-)=sqrt{B(phi->e+e-)*B(phi->mu+mu-)}=(2.89+-0.10+-0.06)*10^{-4} agrees well with the PDG value B(phi->e+e-)=(2.91+-0.07)*10^{-4} confirming mu-e universality. Without additional assumption of mu-e universality the branching ratio B(phi->mu+mu-)=(2.87+-0.20+-0.14)*10^{-4} was obtained.

hep-ex↗
arXiv2001

Search for the radiative decay $η\to π^0 γγ$ in the SND experiment at VEPP-2M

The $η\to π^0 γγ$ decay was investigated by the SND detector at VEPP-2M $e^+e^-$ collider in the reaction $e^+e^-\toϕ\to ηγ$. Here we present the results and some details of this study. We report an upper limit (90% c.l.) $Br(η\to π^0 γγ)<8.4\times 10^{-4}$ as our final result. Our upper limit does not contradict the earlier measurement by GAMS spectrometer. To facilitate future studies a rather detailed review of the problem is also given.

hep-ex↗
arXiv2000

Recent results from SND detector at VEPP-2M

The current status of experiments with SND detector at VEPP-2M $e^+e^-$ collider in the energy range $2E_0=0.4-1.4$ GeV is given. The new results of analysis of $ϕ$ decay into $π^0π^0γ$, $ηπ^0γ$ are based on the full SND statistics corresponding 20 million of $ϕ$ decay. New measurement of $ω\toπ^0π^0γ$ decay and a first observation of $ρ\toπ^0π^0γ$ are presented. The accuracy of many other rare decays of light vector mesons was improved. In the energy range $2E_0=1.0\div1.4$ GeV the cross sections of the processes $e^+e^-\toωπ^0$ and $e^+e^-\toπ^+π^-π^0$ were measured. The results of the fitting of data are discussed.

hep-ex↗
arXiv2000

The process $e^+e^-\toωπ^0\toπ^0π^0γ$ up to 1.4 GeV

The cross section of the $e^+e^-\toωπ^0\toπ^0π^0γ$ reaction was measured by the SND detector at VEPP-2M $e^+e^-$ collider in the energy range from threshold up to 1.4 GeV. Results of the cross section fitting by the sum of $ρ$, $ρ^{\prime}$ and $ρ^{\prime\prime}$ contributions are presented.

hep-ex↗
arXiv2000

The $ϕ(1020)\toπ^0π^0γ$ decay

In the SND experiment at VEPP-2M $e^+e^-$ collider the $ϕ(1020)\toπ^0π^0γ$ decay was studied and its branching ratio was measured: $B(ϕ\toπ^0π^0γ)=(1.221\pm 0.098\pm0.061)\cdot10^{-4}$. It was shown, that $f_0(980)γ$ intermediate state dominates in this decay and the $f_0(980)$-meson parameters were obtained.

hep-ex↗
arXiv2000

The $ϕ\toηπ^0γ$ decay

Rare radiative decay $ϕ\toηπ^0γ$ was studied with SND detector at {VEPP-2M} electron-positron collider and its branching ratio was measured: $B(ϕ\toηπ^0γ)=(0.88\pm0.14\pm0.09)\cdot 10^{-4}$. Significant contribution of the $a_0(980)γ$ intermediate state was observed in the decay. The result is based on total integrated luminosity corresponding to $2\cdot10^7$ produced $ϕ$ mesons.

hep-ex↗
arXiv2000

Decay phi->pi+pi-

The process e+e- ->pi+pi- has been studied with the SND detector at VEPP-2M e+e- collider in the vicinity of phi(1020) resonance. From the analysis of the energy dependence of measured cross section the branching ratio B(phi->pi+pi-)=(7.1+-1.1+-0.9)*10^{-5} and the phase psi_pi=-(34+-4+-3)degrees of interference with the non-resonant pi+pi- production amplitude were obtained.

hep-ex↗
arXiv1999

New Data from SND Detector in Novosibirsk

The current status of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E_0=400-1400 MeV and recent results of data analysis for $ϕ$, $ω$ and $ρ$ decays and e^+e^- annihilation into hadrons are presented.

hep-ex↗
arXiv1999

The process $e^+e^-\toπ^+π^-π^0$ in the energy range 2E_0=1.04 - 1.38 GeV

In the experiment with the SND detector at VEPP-2M e^+e^- collider the process $e^+e^-\toπ^+π^-π^0$ was studied in the energy range 2E_0 from 1.04 to 1.38 GeV. A broad peak was observed with the visible mass $M_{vis}=1220\pm 20$ MeV and cross section in the maximum $σ_0\simeq 4$ nb. The peak can be interpreted as a $ω$-like resonance $ω(1200)$.

hep-ex↗
arXiv1999

Spherical Neutral Detector for VEPP-2M collider

The Spherical Neutral Detector (SND) operates at VEPP-2M collider in Novosibirsk studying e^+e^- annihilation in the energy range up to 1.4 GeV. Detector consists of a fine granulated spherical scintillation calorimeter with 1632 NaI(Tl) crystals, two cylindrical drift chambers with 10 layers of sense wires, and a muon system made of streamer tubes and plastic scintillation counters. The detector design, performance, data acquisition and processing are described.

hep-ex↗