The upper limit of the e+e- partial width of X(3872)

The e+e- decay partial width of the recently observed state, X(3872), is estimated using the ISR data collected at the center of mass energy 4.03 GeV in e+e- annihilation experiment by BES at BEPC. It is found that the product of the e+e- partial width and X(3872) --> pi+ pi- J/psi decay branching fraction is less than 10 eV at 90 % confidence level if the J(PC) of X(3872) is 1(--). Together with the potential models and other information, we conclude that X(3872) is very unlikely to be a vector state.Comment: 5 pages, 1 figur

The interference between virtual photon and 1-- charmonium in e+e-experiment

e+e- Experiments producing charmonium are reviewed. It is found that the contribution of the continuum amplitude via virtual photon was neglected in almost all the experiments and the channels analyzed. It is shown that the contribution of the continuum part may affect the final results significantly in psi(2S) and psi(3770) decays, while the interference between continuum and resonance amplitudes may even affect the J/psi decays as well as the psi(2S) and psi(3770). This should be considered in analyzing the "rho-pi puzzle" between J/psi and psi(2s) decays, and the difference between inclusive hadron and DDbar cross sections in psi(3770) decays.Comment: 6 pages, 2 figure

Effect of soil particle size on the electrochemical corrosion behavior of pipeline steel in saline solution

In this study, by using a standard quartz replace of sandy soil particles, the effect of soil particle size (0.1…0.25 mm, 0.6…1.0 mm) on the electrochemical corrosion behavior of X70 pipeline steel in sandy soil corrosive environment simulated by 3.5 wt.% sodium chloride (NaCl) was investigated through polarization curve and electrochemical impedance spectroscopy (EIS) technology. The results indicated that the polarization resistance of X70 steel decreased with a decreasing particle size. For all polarization curves the right shift of cathodic branch with a decreasing particle size is observed. The corrosion of X70 steel is controlled by the cathode process diffusion and oxygen reduction at the metalenvironment interface, the intensity of which increases with the decreasing particle size.З допомогою методів потенціодинамічних поляризаційних кривих та електрохімічної імпедансної спектроскопії (EIS) досліджено корозійну поведінку трубопровідної сталі Х70 у ґрунтовому середовищі, яке змодельовано розчином 3,5 wt.% NaCl з частинками кварцового піску різного розміру (0,1…0,25 і 0,6…1,0 mm). Встановлено, що швидкість корозії сталі зростає зі зменшенням розміру частинок ґрунту, про що свідчить зниження її поляризаційного опору, а також зсув катодних гілок поляризаційних кривих вправо. Зроблено висновок, що в цьому випадку корозію сталі контролює катодний процес відновлення кисню на межі поділу метал–середовище, інтенсивність якого зростає зі зменшенням розміру частинок ґрунту.С помощью методов потенциодинамических поляризационных кривых и электрохимической импедансной спектроскопии (EIS) исследовано коррозионное поведение трубопроводной стали Х70 в почвенной среде, которую моделировали раствором 3,5 wt.% NaCl с частицами кварцевого песка разного размера (0,1…0,25 и 0,6...1,0 mm). Установлено, что скорость коррозии стали растет с уменьшением размера частиц почвы, о чем свидетельствует снижение ее поляризационного сопротивления, а также сдвиг катодных ветвей поляризационных кривых вправо. Сделан вывод, что в данном случае коррозию стали контролирует катодный процесс возобновления кислорода на грани деления металл–среда, нитенсивность которого растет с уменьшением размера частиц почвы

The Form Factors of omega pi0 and pi+ pi- at psi(2S)

The measurements of psi(2S) -> omega pi0 and psi(2S) -> pi+ pi- in e+e- experiments are examined. It is found that the non-resonance virtual photon annihilation gives large contributions to the observed cross sections of these two processes. By including this contribution, the form factors and branching fractions of these two decay modes are revised.Comment: 6 pages, 1 figures(two diagrams), Phys. Lett. B557 (2003) 192-19

Determining the upper limit of Gamma_{ee} for the Y(4260)

By fitting the R values between 3.7 and 5.0 GeV measured by the BES collaboration, the upper limit of the electron width of the newly discovered resonance Y(4260) is determined to be 580 eV at 90% C.L. Together with the BABAR measurement on the product of Gamma_{ee} and BR(Y(4260) --> pi+pi- J/psi), this implies a large decay width of Y(4260) --> pi+pi- J/psi final states.Comment: 8 pages, 4 figure

Measuring psi(3770) --> rho pi in e+e- experiment

In S- and D-wave mixing scheme, the branching ratio of psi(3770) --> rho pi is estimated. Together with the continuum cross section of rho pi estimated by form factor, the observed cross section of rho pi production at psi(3770) in e+e- experiment is calculated taking into account the interference effect between the resonance and continuum amplitudes and the initial state radiative correction. The behavior of the cross section reveals that the disappearance of rho pi signal just indicates the existence of the corresponding branching ratio B(psi(3770) --> rho pi) at the order of 10 to the minus fourth.Comment: 6 pages, 3 figure

Baryon Antibaryon Nonets

The baryon-antibaryon SU(3) nonets are proposed as a scheme to classify the increased number of experimentally observed enhancements near the baryon antibaryon mass threshold. The scheme is similar to the Fermi-Yang-Sakata model, which was put forth about fifty years ago in explaining the mesons observed at that time. According to the present scheme, many new baryon-antibaryon bound states are predicted, and their possible productions in quarkonium decays and B decays are suggested for experimental search.Comment: 5 pages, 1 figur

Properties and Performance of Two Wide Field of View Cherenkov/Fluorescence Telescope Array Prototypes

A wide field of view Cherenkov/fluorescence telescope array is one of the main components of the Large High Altitude Air Shower Observatory project. To serve as Cherenkov and fluorescence detectors, a flexible and mobile design is adopted for easy reconfiguring of the telescope array. Two prototype telescopes have been constructed and successfully run at the site of the ARGO-YBJ experiment in Tibet. The features and performance of the telescopes are presented

A Measurement of Psi(2S) Resonance Parameters

Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been measured in the vicinity of the Psi(2S) resonance using the BESII detector operated at the BEPC. The Psi(2S) total width; partial widths to hadrons, pi+pi- J/Psi, muons; and corresponding branching fractions have been determined to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)= (2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)= (97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%, respectively.Comment: 8 pages, 6 figure

Measurements of the Mass and Full-Width of the ηc\eta_c Meson

In a sample of 58 million $J/\psi$ events collected with the BES II detector, the process J/$\psi\to\gamma\eta_c$ is observed in five different decay channels: $\gamma K^+K^-\pi^+\pi^-$, $\gamma\pi^+\pi^-\pi^+\pi^-$, $\gamma K^\pm K^0_S \pi^\mp$ (with $K^0_S\to\pi^+\pi^-$), $\gamma \phi\phi$ (with $\phi\to K^+K^-$) and $\gamma p\bar{p}$. From a combined fit of all five channels, we determine the mass and full-width of $\eta_c$ to be $m_{\eta_c}=2977.5\pm1.0 ({stat.})\pm1.2 ({syst.})$ MeV/$c^2$ and $\Gamma_{\eta_c} = 17.0\pm3.7 ({stat.})\pm7.4 ({syst.})$ MeV/$c^2$.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.