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S. I. Eidelman

Publications and source records attributed to S. I. Eidelman.

52 records · Page 3Linked to original sources
arXiv2010

Measurement of Γ_{ee}(J/ψ)*Br(J/ψ->e^+e^-) and Γ_{ee}(J/ψ)*Br(J/ψ->μ^+μ^-)

The products of the electron width of the J/ψmeson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are Γ_{ee}(J/ψ)*Br(J/ψ->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, Γ_{ee}(J/ψ)*Br(J/ψ->μ^+μ^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations Γ_{ee}\times(Γ_{ee}+Γ_{μμ})/Γ=(0.6641\pm0.0082\pm0.0100) keV, Γ_{ee}/Γ_{μμ}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming eμuniversality and using the world average value of the lepton branching fraction, we also determine the leptonic Γ_{ll}=5.59\pm0.12 keV and total Γ=94.1\pm2.7 keV widths of the J/ψmeson.

hep-ex↗
arXiv2010

Recent results from the KEDR Detector

We report results of experiments performed with the KEDR detector at the VEPP-4M e+e- collider. They include precise measurement of the D0 and D+- meson masses, determination of the psi(3770) resonance parameters, and a search for narrow resonances in e+e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV.

hep-ex↗
arXiv2009

Charmed Exotics

These are the mini-proceedings of the CHARMEX workshop. The meeting focused on recent developments in charm spectroscopy, especially on the possible role of the states that do not fit into the quark model classification, the so-called exotic states. The goal of this write-up is to provide the community with a short summary of the individual talks as well as a comprehensive, up-to-date list of relevant references.

hep-ph↗
arXiv2009

τlepton decays and CVC

We use experimental data on $e^+e^- \to η(η^{\prime})π^+π^-$ and conservation of vector current to estimate the branching fractions of $τ^-$ decay to $η(η^{\prime})π^-π^0ν_τ$. The obtained values are compared to the experimental results.

hep-ex↗
arXiv2009

Standard Model Predictions for the Muon $(g-2)/2$

The current status of the Standard Model predictions for the muon anomalous magnetic moment is described. Various contributions expected in the Standard Model are discussed. After the reevaluation of the leading-order hadronic term based on the new \ep data, the theoretical prediction is more than three standard deviations lower than the experimental value.

hep-ex↗
arXiv2008

Measurement of e+e- -> phi -> K+K- cross section with the CMD-2 detector at VEPP-2M Collider

The process e+ e- -> phi -> K+ K- has been studied with the CMD-2 detector using about 542 000 events detected in the center-of-mass energy range from 1.01 to 1.034 GeV. The systematic error of the cross section is estimated to be 2.2%. The phi(1020) meson parameters in the phi -> K+K- decay channel have been measured: sigma_0(phi-> K+K-) = 2016 +- 8 +- 44 nb, m(phi) = 1019.441 +- 0.008 +- 0.080 MeV/c2, Gamma(phi) = 4.24 +- 0.02 +- 0.03 MeV, B(e+e-)B(K+K-) = (14.27 +- 0.05 +- 0.31)*10(-5).

hep-ex↗
arXiv2006

Study of hyperfine structure in simple atoms and precision tests of the bound state QED

We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.

hep-ph↗
arXiv2003

Reanalysis of Hadronic Cross Section Measurements at CMD-2

The updated results of the precise measurements of the processes e+e-->rho->pi+pi-, e+e-->omega->pi+pi-pi0 and e+e-->phi->KLKS performed by the CMD-2 collaboration are presented. The update appeared necessary due an overestimate of the integrated luminosity in previous analyses.

hep-ex↗
arXiv2002

Recent results from e+ e- --> hadrons

New results on the low energy e+ e- annihilation into hadrons from Novosibirsk and Beijing are described. Implications of the new measurements for the evaluation of the hadronic contribution to the muon anomalous magnetic moment are discussed.

hep-ex↗
arXiv2002

Novosibirsk hadronic currents for tau -> 4pi channels of tau decay library TAUOLA

The new parameterization of form factors developed for 4pi channels of the tau lepton decay and based on Novosibirsk data on e^+e^- -> 4pi has been coded in a form suitable for the TAUOLA Monte Carlo package. Comparison with results from TAUOLA using another parameterization, i.e. the CLEO version of 1998 is also included.

hep-ph↗
arXiv1999

Spectroscopy at B-factories Using Hard Photon Emission

The process of hard photon emission by initial electrons (positrons) at B-factories is discussed. It is shown that studies of the bottomonium spectroscopy will be feasible for the planned integrated luminosity of the B-factory experiments.

hep-ph↗
arXiv1999

On the role of $a_1(1260)$ meson in the $τ\to 4πν_τ$ decay

We demonstrate that a simple model successfully describing experimental data for the process $\epm\to 4π$ can also qualitatively account for the data of CLEOII and ALEPH obtained recently for the decay $τ\to 4πν_τ$. The model is based on the assumption of the $a_1(1260)π$ and $ωπ$ dominance as intermediate states. Our observation is in contrast with the claim by ARGUS that the $ρ$-meson signal in the $τ\to 4πν_τ$ decay can not be explained by the $a_1π$ intermediate state.

hep-ph↗
arXiv1994

$ρ\to 4π$ DECAY

The decay modes $ρ^0 \to 2π^+ 2π^-$ and $ρ^0 \to 2π^0 π^+ π^-$ are considered in the framework of the low energy effective chiral Lagrangian. The obtained values of the decay widths $Γ(ρ^0\to 2 π^+ 2 π^-)=$ $(16 \pm 1){\rm keV}$ and $Γ(ρ^0\to 2 π^0 π^+ π^-)= (6.0 \pm 0.2)$keV do not contradict the existing upper limits and seem to be big enough for the corresponding processes to be observed in future high luminosity experiments.

hep-ph↗