Gluon condensate and c-quark mass in pseudoscalar sum rules at 3-loop order

Charmonium sum rules for pseudoscalar 0^{-+} state eta_c(1S) are analyzed within perturbative QCD and Operator Product Expansion. The perturbative part of the pseudoscalar correlator is considered at alpha_s^2 order and the contribution of the gluon condensate is taken into account with alpha_s correction. The OPE series includes the operators of dimension D=6,8 computed both in the instanton and factorization model. The method of moments in MS-bar scheme allows to establish acceptable values of the charm quark mass and gluon condensate, using the experimental mass of eta_c. In result of the analisys the charm quark mass is found to be m_c(m_c)=1.26+-0.02 GeV independently of the condensate value. The sensitivity of the results to various approximations for the massive 3-loop pseudoscalar correlator is discussed.Comment: 19 pages, 1 latex + 5 eps files. v2: Operators of dimension D=8 included; the condensate restriction relaxed; c-quark mass is found m_c(m_c)=1.26+-0.02 GeV independently of other sum rules and condensate value. To appear in JHE

Current state of the research on optoacoustic fiber-optic ultrasonic transducers based on thermoelastic effect and fiber-optic interferometric receivers

The work is devoted to an overview of the current state of optoacoustic fiber-optic ultrasonic transducers based on thermoelastic effect and fiber-optic interference receivers, its scope, technologies and materials used, the advantages and disadvantages of different methods and the prospects for the development of the industry.The work has been supported by the Russian Science Foundation 21-12-00304

New 15 MeV electron accelerator for non-destructive testing

A 15 MeV accelerator with the dose rate from 80 to 120 Gy/min at 1m from the target has been designed and manufactured in NPK LUTS, the D.V.Efremov Institute, NIIEFA. The accelerator is intended for nondestructive testing (radiography, introscopy, tomography) of large scale products. Under tests an X-ray beam with the boundary energy of 15-16 MeV and dose rate of 100 Gy/min has been produced. When operating with longer pulse lengths of the accelerated electron current, the beam power was up to 140 Gy/min; with lower currents the 18 MeV energy was attained at a dose rate of 40-50 Gy/min. Biperiodic accelerating structure with axial coupling cells is applied in the accelerator. The accelerating structure buncher provides RF-focusing of the electron beam, therefore there is no need for focusing the solenoid. The focus spot diameter is no more than 2mm. To provide the electron beam stability, the accelerator is equipped with a system for automatic frequency tuning (AFT). The AFT system ensures both coarse tuning of the driver frequency against the temperature of the accelerating structure and fine tuning - against the minimum reflected power. The anode voltage of the klystron amplifier is stabilized by using a de-Q-ing system. A charging choke and pulse forming network (PFN) are located inside the irradiator unit to increase the distance between the modulator and irradiator up to 100m and to reduce losses when high-voltage high-current pulses are transmitted. The low-voltage klystron (anode voltage up to 55 kV) applied in the accelerator allows reducing the machine weight and dimensions (1100 kg and 2040x880x920mm). The accelerator is equipped with a PC-based automatic control system. In the accelerator intended for the radiographic inspection there is an external collimator with movable diaphragm jaws for testing small fragments of an inspected product

Small-size 2.5 MeV electron accelerator with local radiation shielding

A novel design of a 2.5 MeV small-size linear electron accelerator with local radiation shielding is presented in the paper. The accelerator is intended for the use in mobile introscopic facilities. The main design approaches, weight / dimensions and results of factory tests are given

Mesoscopic phase separation in La2CuO4.02 - a 139La NQR study

In crystals of La2CuO4.02 oxygen diffusion can be limited to such small length scales, that the resulting phase separation is invisible for neutrons. Decomposition of the 139La NQR spectra shows the existence of three different regions, of which one orders antiferromagnetically below 17K concomitantly with the onset of a weak superconductivity in the crystal. These regions are compared to the macroscopic phases seen previously in the title compound and the cluster-glass and striped phases reported for the underdoped Sr-doped cuprates.Comment: 4 pages, RevTeX, 5 figures, to be published in PR

Nanoscale Processing by Adaptive Laser Pulses

We theoretically demonstrate that atomically-precise ``nanoscale processing" can be reproducibly performed by adaptive laser pulses. We present the new approach on the controlled welding of crossed carbon nanotubes, giving various metastable junctions of interest. Adaptive laser pulses could be also used in preparation of other hybrid nanostructures.Comment: 4 pages, 4 Postscript figure

Measurement of RudsR_{\text{uds}} and RR between 3.12 and 3.72 GeV at the KEDR detector

Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have measured the values of $R_{\text{uds}}$ and $R$ at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or better than $3.3\%$ at most of energy points with a systematic uncertainty of about $2.1\%$. At the moment it is the most accurate measurement of $R(s)$ in this energy range

New precise determination of the \tau lepton mass at KEDR detector

The status of the experiment on the precise $\tau$ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the $\tau^+\tau^-$ cross section behaviour around the production threshold. The preliminary result based on 6.7 pb$^{-1}$ of data is $m_{\tau}=1776.80^{+0.25}_{-0.23} \pm 0.15$ MeV. Using 0.8 pb$^{-1}$ of data collected at the $\psi'$ peak the preliminary result is also obtained: $\Gamma_{ee}B_{\tau\tau}(\psi') = 7.2 \pm 2.1$ eV.Comment: 6 pages, 8 figures; The 9th International Workshop on Tau-Lepton Physics, Tau0

Measurement of \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-) and \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)

The products of the electron width of the J/\psi meson 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 \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations \Gamma_{ee}\times(\Gamma_{ee}+\Gamma_{\mu\mu})/\Gamma=(0.6641\pm0.0082\pm0.0100) keV, \Gamma_{ee}/\Gamma_{\mu\mu}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming e\mu universality and using the world average value of the lepton branching fraction, we also determine the leptonic \Gamma_{ll}=5.59\pm0.12 keV and total \Gamma=94.1\pm2.7 keV widths of the J/\psi meson.Comment: 7 pages, 6 figure

Search for narrow resonances in e+ e- annihilation between 1.85 and 3.1 GeV with the KEDR Detector

We report results of a search for narrow resonances in e+ e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e+ e- collider. The upper limit on the leptonic width of a narrow resonance Gamma(R -> ee) Br(R -> hadr) < 120 eV has been obtained (at 90 % C.L.)