Showing papers by "V. B. Golubev published in 2000"
TL;DR: In the SND experiment at VEPP-2M e + e − collider the φ (1020)→ π 0 π γ 0 γ decay was studied and its branching ratio was measured as discussed by the authors, and it was shown that f 0 (980) γ intermediate state dominates in this decay.
91 citations
TL;DR: In this article, the branching ratios obtained in the SND experiment at the VEPP-2M collider in the energy region of the ''phi'' meson were compared with different theoretical models.
Abstract: The processes \(e^+e^-\rightarrow\eta\gamma, \pi^0\gamma\rightarrow 3\gamma\) were studied in the SND experiment at the VEPP-2M collider in the energy region of the \(\phi\) meson. The branching ratios obtained in this study are \(\mathrm{Br}(\phi \rightarrow \eta \gamma)=(1.338\pm 0.012\pm 0.052)\)% and \(\mathrm{Br}(\phi \rightarrow \pi ^{0}\gamma )=(1.226\pm 0.036_{-0.089}^{+0.096})\times 10^{-3} \). A comparison of the experimental data with different theoretical models was performed.
55 citations
TL;DR: In this paper, the authors measured the cross section of the e−e−→ωπ0→π0π0γ reaction at VEPP-2M e+e− collider in the energy range from threshold up to 1.4 GeV.
54 citations
[...]
TL;DR: In this paper, the branching ratio of rare radiative decay φ → ηπ 0 γ was studied with SND detector at VEPP-2M electron-positron collider and its branching ratio was measured.
41 citations
TL;DR: In this paper, the e + e − → ωπ 0 → π 0 π γ 0 γ γ decay process was investigated in the SND experiment at the VEPP-2M collider, where a narrow energy interval near the φ -meson was scanned.
29 citations
[...]
TL;DR: In this paper, the SND detector at VEPP-2M e + e − collider in the vicinity of φ (1020) resonance has been studied with a cross section analysis of measured cross section.
14 citations
TL;DR: In this article, the decay probabilities were found to be B(ω→ π0π0γ)= (7.8 ± 2.7± 2.0)×10−5 and B(π→ ρ 0π 0γ = (4.4 ± 0.2)× 10−5.
Abstract: The e
+
e
−→π0π0 γreaction was studied in the energy range 0.36–0.97 GeV on a VEPP-2M e
+
e
− collider with an SND detector. The decay probabilities were found to be B(ω→ π0π0γ)= (7.8 ±2.7±2.0)×10−5 and B(π→ π0π0γ)= (4.8
−1.8
+3.4
±0.2)×10−5.
13 citations
27 Jul 2000
TL;DR: The BABAR detector at SLAC PEP-II has been recording data at energies on and around the Upsilon(4S) resonance since May 1999 as mentioned in this paper, and the performance presently achieved by the experiment in the areas of tracking, vertexing, calorimetry and particle identification is reviewed.
Abstract: The BABAR detector, situated at the SLAC PEP-II asymmetric e^+e^- collider, has been recording data at energies on and around the Upsilon(4S) resonance since May 1999. In this paper, we briefly describe the PEP-II B Factory and the BABAR detector. The performance presently achieved by the experiment in the areas of tracking, vertexing, calorimetry and particle identification is reviewed. Analysis concepts that are used in the various papers submitted to this conference are also discussed.
13 citations
[...]
TL;DR: In this paper, the SND detector at VEPP-2M e+e-collider in the vicinity of phi(1020) resonance has been used to study the process e + e − π+pi+pi.
Abstract: 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.
11 citations
27 Jul 2000
TL;DR: In this paper, the flight length difference between the two B mesons which are pair-produced in the Y(4S) decay was determined from the two mesons' trajectories.
Abstract: Data collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC are used to study the lifetimes of the B^0 and B^+ mesons. The data sample consists of 7.4 fb-1 collected near the Y(4S) resonance. B^0 and B^+ mesons are fully reconstructed in several exclusive hadronic decay modes to charm and charmonium final states. The B lifetimes are determined from the flight length difference between the two B mesons which are pair-produced in the Y(4S) decay. The preliminary measurements of the lifetimes are tau_B0 = 1.506+/-0.052(stat)+/-0.029(syst) ps, tau_B+ = 1.602+/-0.049(stat)+/-0.035(syst) ps, and of their ratio is tau_B+/tau_B0 = 1.065+/-0.044(stat)+/-0.021(syst)
6 citations
TL;DR: In this article, the branching ratio of the rare radiative decay was measured with SND detector at the VPP-2M electron-positron collider and its branching ratio was measured: $B(\phi\to\eta\pi^0\gamma)=(0.88\pm0.14\pm 0.09)\cdot 10^{-4} ).
Abstract: Rare radiative decay $\phi\to\eta\pi^0\gamma$ was studied with SND detector at {VEPP-2M} electron-positron collider and its branching ratio was measured: $B(\phi\to\eta\pi^0\gamma)=(0.88\pm0.14\pm0.09)\cdot 10^{-4}$. Significant contribution of the $a_0(980)\gamma$ intermediate state was observed in the decay. The result is based on total integrated luminosity corresponding to $2\cdot10^7$ produced $\phi$ mesons.
TL;DR: In this article, the decay branching ratios B(φ→ηγ)=(1.353±0.052)×10−2, B(ω→δ)=(4.62±0.,71±0,18)× 10−4, and B(ρ→γ)=(2.31±0.15)×9−4 were measured.
Abstract: The e
+
e
−→ηγ→7γ process was studied in the energy range 2E=600–1060 MeV with an SND detector on a VEPP-2M e
+
e
− collider. The decay branching ratios B(φ→ηγ)=(1.353±0.011±0.052)×10−2, B(ω→ηγ)=(4.62±0.71±0.18)×10−4, and B(ρ→ηγ)=(2.73±0.31±0.15)×10−4 were measured.
TL;DR: The results of the SND experiment at the VEPP-2M collider on the QED processes with production at large angles are presented in this article, where the energy and angular distributions of the final particles were studied.
Abstract: Results of the SND experiment at the VEPP-2M $e^+e^-$
collider on the QED processes $e^+e^-\rightarrow e^+e^-\gamma$
and $e^+e^-\rightarrow e^+e^-\gamma\gamma$
with production at large angles are presented. The energy and angular distributions of the final particles were studied. No deviations from QED were found, with an accuracy of 3.8% for the first process and 10.3% for the second.
27 Jul 2000
TL;DR: In this article, preliminary results of a search for charmless two-body B decays to charged pions and kaons using data collected by the BABAR detector at the Stanford Linear Accelerator Center's PEP-II storage ring were presented.
Abstract: We present preliminary results of a search for charmless two-body B decays to charged pions and kaons using data collected by the BABAR detector at the Stanford Linear Accelerator Center's PEP-II storage ring. In a sample of 8.8 million produced B-anti-B pairs we measure the branching fractions B(B^0 --> pi^+pi^-) = (9.3^{+2.6}_{-2.3}^{+1.2}_{-1.4}) x 10^{-6} and B(B^0 --> K^+\pi^-) = (12.5^{+3.0}_{-2.6}^{+1.3}_{-1.7}) x 10^{-6}, where the first uncertainty is statistical and the second is systematic. For the decay B^0 --> K^+K^- we find no significant signal and set an upper limit of B(B^0 --> K^+K^-) 6.6 x 10^{-6} at the 90% confidence level.
TL;DR: In this article, the processes e + e − → μ + μ − and e+ e− → π + π − have been studied with SND detector at VEPP-2M e− e − collider in the vicinity of f(1020) resonance.
27 Jul 2000
TL;DR: In this article, a preliminary study of time dependence of B^0-anti-B^0 oscillations using dilepton events is presented, where the flavor of the B meson is determined by the charge sign of the lepton and the time evolution of the oscillations is studied by reconstructing the time difference between the decays of B mesons produced by the Y(4S) decay.
Abstract: A preliminary study of time dependence of B^0-anti-B^0 oscillations using dilepton events is presented. The flavor of the B meson is determined by the charge sign of the lepton. To separate signal leptons from cascade and fake leptons we have used a method which combines several discriminating variables in a neural network. The time evolution of the oscillations is studied by reconstructing the time difference between the decays of the B mesons produced by the Y(4S) decay. With an integrated luminosity of 7.7 fb-1 collected on resonance by BABAR at the PEP-II asymmetric B Factory, we measure the difference in mass of the neutral B eigenstates, Delta_mB0 to be (0.507+/-0.015+/-0.022) x 10^{12} hbar-s^{-1}.
27 Jul 2000
TL;DR: In this article, preliminary results of a search for charmless two-body B decays to charged pions and kaons using data collected by the BABAR detector at the Stanford Linear Accelerator Center's PEP-II storage ring were presented.
Abstract: We present preliminary results of a search for charmless two-body B decays to charged pions and kaons using data collected by the BABAR detector at the Stanford Linear Accelerator Center's PEP-II storage ring. In a sample of 8.8 million produced B-anti-B pairs we measure the branching fractions B(B^0 --> pi^+pi^-) = (9.3^{+2.6}_{-2.3}^{+1.2}_{-1.4}) x 10^{-6} and B(B^0 --> K^+\pi^-) = (12.5^{+3.0}_{-2.6}^{+1.3}_{-1.7}) x 10^{-6}, where the first uncertainty is statistical and the second is systematic. For the decay B^0 --> K^+K^- we find no significant signal and set an upper limit of B(B^0 --> K^+K^-) 6.6 x 10^{-6} at the 90% confidence level.
27 Jul 2000
TL;DR: In this paper, the authors presented preliminary results of a search for several exclusive charmless hadronic B decays from electron-positron annihilation data collected by the BABAR detector near the Y(4S) resonance.
Abstract: We present preliminary results of a search for several exclusive charmless hadronic B decays from electron-positron annihilation data collected by the BABAR detector near the Y(4S) resonance. These include three-body decay modes with final states h^{+/-}h^{-/+}h^{+/-} and h^{+/-}h^{-/+}pi^0, and quasi-two-body decay modes with final states X^0 h and X^0 K0S, where h = pi or K and X^0 = eta^' or omega. We find B(B^0 --> rho^(-/+)pi^(+/-)) = (49+/-13^{+6}_{-5}) x 10^{-6} and B(B^+ --> eta^' K^+) = (62+/-18+/-8) x 10^{-6} and present upper limits for eight other decays.
TL;DR: In this paper, the relative decay probability B(φ → ηγ) = (1.259 ± 0.059)% in the decay channel η → π+π−π0 has been measured in an experiment using a spherical neutral detector in the VEPP-2M electron-positron storage ring.
Abstract: The relative decay probability B(φ → ηγ) = (1.259 ± 0.030 ± 0.059)% in the decay channel η → π+π−π0 has been measured in an experiment using a spherical neutral detector in the VEPP-2M electron-positron storage ring. The result agrees with the tabulated value and with measurements of this probability using the spherical neutral detector in other η-meson decay channels.
01 Jan 2000
27 Jul 2000
TL;DR: In this article, the two B^0 decay processes were studied by means of a partial reconstruction technique using a data sample collected with the BABAR detector at the PEP-II storage ring.
Abstract: The two B^0 decay processes B^0 --> D^{*-}pi^+ and B^0 --> D^{*-}l^+nu have been studied by means of a partial reconstruction technique using a data sample collected with the BABAR detector at the PEP-II storage ring. To increase statistics, only the soft pi^- from the decay D^{*-} --> pi^-D^0 was used in association with either an oppositely-charged high-momentum pion or lepton. Events were then identified by exploiting the constraints from the simple kinematics of Y(4S) decays. A clear signature is obtained in each case. The position of the B^0 decay point was obtained from the reconstructed pi^+(l^+)pi^- vertex. The position of the other anti-B^0 in the event was also determined. Taking advantage of the boost given to the Y(4S) system by the asymmetric beam energies of PEP-II, the lifetime of the B^0 meson has been measured from the separation distance between the two vertices along the beam direction. The preliminary results are tau_B0 = 1.55+/-0.05+/-0.07 ps, tau_B0 = 1.62+/-0.02+/-0.09 ps, respectively for the B^0 --> D^{*-}pi^+ and B^0 --> D^{*-}l^+nu channels.