Searcharxiv⌕ Search

arXiv subjects

A. D. Bukin

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

At least 37 records · Page 2Linked to original sources

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

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↗

Medium energy calorimetry at SND: techniques and performances on physics

SND (Spherical Neutral Detector) is a general purpose nonmagnetic detector, successfully operating at Novosibirsk VEPP-2M collider during last four years in the center of mass energy range from 400 MeV up to 1400 MeV. Its crucial part is a 3-layer, fine grained, spherical NaI(Tl) electromagnetic calorimeter consisted of 1632 individual counters. Here we present a detailed description of the calorimeter and its performance, including such topics as calorimeter design, electronics, calibration, energy and spatial resolutions, particle identification. The calorimeter performance is illustrated by examples from the current studies of different physical processes.

hep-ex↗

Upper limit on the Ks ---> 3 pi0 decay

The search for CP-violating K_S\to3π^0 decay was performed with SND detector at VEPP-2M e^+e^- collider. The total amount of data corresponding to 7 million produced K_S mesons was analyzed. No candidate events were found, giving an upper limit of the decay branching ratio: Br(K_S\to3π^0) < 1.4\cdot10^{-5} at 90% confidence level.

hep-ex↗

First Observation of PHI(1020)--->PI0+PI0+GAMMA Decay

In the SND experiment at the VEPP-2M electron-positron collider the PHI(1020)--->PI0+PI0+GAMMA decay was studied. The branching ratio B(PHI--->PI0+PI0+GAMMA)=(1.14+-0.10+-0.12)x10^{-4} was measured. It was shown, that the F0(980)GAMMA mechanism dominates in this decay and the 4-quark model of F0(980) describes our data most consistently.

hep-ex↗

Experiments at VEPP-2M with SND detector

Short overview of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E = 400 - 1400 MeV and preliminary results of data analysis are presented.

hep-ex↗

Energy calibration of the NaI(Tl) calorimeter of the SND detector using cosmic muons

The general purpose spherical nonmagnetic detector (SND) is now taking data at VEPP-2M $e^+e^-$ collider in BINP (Novosibirsk) in the centre of mass energy range of $0.2 ÷1.4$ GeV. The energy calibration of the NaI(Tl) calorimeter of the SND detector with cosmic muons is described. Using this method, the energy resolution of $5.5 % (σ)$ for 500 MeV photons was achieved.

physics.ins-det↗

Study of $Δ(1232)$ isobar electroproduction at VEPP-2M $e^+e^-$ collider

Results from the Spherical Nonmagnetic Detector (SND) on $Δ(1232)$ isobar electroproduction in the collisions of beam electrons (positrons) and residual gas nuclei in the VEPP-2M $e^+e^-$ collider are presented. On the basis of the obtained data the expected counting rate of this process in future high luminosity $e^+e^-$ colliders (~$ϕ$-, $c$-$τ$- and $b$-factories) was estimated.

hep-ex↗