Shi Huanzhang

Measurement of the Σ¯− lifetime and direct comparison with the Σ+ lifetime

R. F. Barbosa, I. F. M. Albuquerque, Nikolay Bondar, R. A. Carrigan et autres

We have measured the lifetime of the ${\overline{\ensuremath{\Sigma}}}^{\ensuremath{-}}$ using the Fermilab Proton Center 375 GeV/$c$ charged hyperon beam. We obtained $(80.43\ifmmode\pm\else\textpm\fi{}0.80\ifmmode\pm\else\textpm\fi{}0.14)$ ps. We also measured the lifetime of the ${\ensuremath{\Sigma}}^{+},$ obtaining $(80.38\ifmmode\pm\else\textpm\fi{}0.40\ifmmode\pm\else\textpm\fi{}0.14)$ ps, in agreement with the Particle Data Group value. A …

Experimental study of hadron inclusive production in J / psi energy region

Bai Jingzhi, Bian Jianguo, Chai Zhengwei, Guang‐Pei Chen et autres

The mean multiplicities of mesons π±, π0, K±, Ks0, K*0, K*±, and φ and baryons p, Ξ±, and ∑± (1385) are measured for the first time at J/ψ region with 200,000 events collected at the BEPC with the BES detector. The results …

Measurement of the branching ratios for J / psi --> gamma pi0, gamma eta, gamma eta' --> 3gamma on the BES

Jing-Zhi Bai, Xiaonan Li, Ze-Pu Mao, Hong Shen et autres

Measurement of the Branching Ratios for J/ ψ → γπ 0 , γη '→3 γ on the BES

Bai Jingzhi, Bian Jianguo, Chai Zhengwei, Guang‐Pei Chen et autres

Decays of the J/ψ resonance into the three-photon final state are investigated. Branching ratios for the decays of J/ψ→γπ0 and J/ψ→γη' are determined to be Br(J/ψ→γπ0)=(4.6±1.1)×10-5 and Br(J/ψ→γη')=(4.12±0.82)—10-3. The ratio of the two decay widths, Γ(J/ψ→γη')/Γ(J/ψ→γη),is 4.79±0.85. This value agrees weM with …

pt and xF dependence of the polarization of Σ+ hyperons produced by 800 GeV/cprotons

A. Morelos, I. F. M. Albuquerque, N. F. Bondar, R. A. Carrigan et autres

We utilize the angle and momentum resolution of our apparatus to study the polarization of 375 GeV/c ${\mathrm{\ensuremath{\Sigma}}}^{+}$ hyperons produced by 800 GeV/c protons incident on a Cu target. By examining in detail two of our high statistics data samples, we find …

Measurement of the branching ratio and asymmetry parameter for the Σ+ →pγ radiative decay

Steven C. Timm, I. F. M. Albuquerque, N. F. Bondar, R. A. Carrigan et autres

We have measured the branching ratio for the hyperon radiative decay ${\mathrm{\ensuremath{\Sigma}}}^{+}$\ensuremath{\rightarrow}p\ensuremath{\gamma} using the Fermilab polarized charged hyperon beam. This measurement and our previously published result on the asymmetry parameter in the same decay are part of Fermilab experiment E761. We find …

Experimental study of f0(975) in J / psi decays

Jing-Zhi Bai, Xiaonan Li, Zepu Mao, Hong Shen et autres

Measurement of the branching ratio for the Ξ− → Σ− γ radiative decay

T. Dubbs, I. F. M. Albuquerque, N. F. Bondar, R. A. Carrigan et autres

We have measured the branching ratio for the hyperon radiative decay ${\mathrm{\ensuremath{\Xi}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Sigma}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\gamma} from a sample of 211\ifmmode\pm\else\textpm\fi{}33 events obtained in the polarized 375 GeV/c charged hyperon beam at Fermilab. We find B(${\mathrm{\ensuremath{\Xi}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Sigma}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\gamma}/${\mathrm{\ensuremath{\Xi}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Lambda}}}^{0}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$)=(1.22\ifmmode\pm\else\textpm\fi{}0.23\ifmmode\pm\else\textpm\fi{}0.06)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ where the quoted errors are statistical and systematic, respectively. We …

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Measurement of the magnetic moments of the Σ+ and Σ ¯− hyperons

A. Morelos, I. F. M. Albuquerque, N. F. Bondar, R. A. Carrigan et autres

We have measured the magnetic moments of the ${\mathrm{\ensuremath{\Sigma}}}^{+}$ and \ensuremath{\Sigma}\ifmmode\bar\else\textasciimacron\fi{} $^{\mathrm{\ensuremath{-}}}$ hyperons produced by 800-GeV protons incident on a Cu target. We determine the ${\mathrm{\ensuremath{\Sigma}}}^{+}$ magnetic moment to be (2.4613\ifmmode\pm\else\textpm\fi{}0.0034\ifmmode\pm\else\textpm\fi{}0.0040)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$ where the uncertainties are statistical and systematic, respectively. In this first …

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First observation of magnetic moment precession of channeled particles in bent crystals

D Chen, I. F. M. Albuquerque, V. V. Baublis, N. F. Bondar et autres

Spin precession of channeled particles in bent crystals has been observed for the first time. Polarized ${\mathrm{\ensuremath{\Sigma}}}^{+}$ were channeled using bent Si crystals. These crystals provided an effective magnetic field of 45 T which resulted in a measured spin precession of 60\ifmmode\pm\else\textpm\fi{}17\ifmmode^\circ\else\textdegree\fi{}. …

Measurement of the asymmetry parameter in the hyperon radiative decay Σ+ →pγ

M. Foucher, I. F. M. Albuquerque, N. F. Bondar, R. A. Carrigan et autres

We have measured the asymmetry parameter (${\mathrm{\ensuremath{\alpha}}}_{\ensuremath{\gamma}}$) in the hyperon radiative decay ${\mathrm{\ensuremath{\Sigma}}}^{+}$\ensuremath{\rightarrow}p\ensuremath{\gamma} with a sample of 34 754\ifmmode\pm\else\textpm\fi{}212 events obtained in a polarized charged hyperon beam experiment at Fermilab. We find ${\mathrm{\ensuremath{\alpha}}}_{\ensuremath{\gamma}}$=-0.720\ifmmode\pm\else\textpm\fi{}0.086\ifmmode\pm\else\textpm\fi{}0.045, where the quoted errors are statistical and systematic, respectively.

Experimental measurement of the mass of the tau lepton at the Beijing Electron Positron Collider (BEPC)

Jing-Zhi Bai, Mao Ze-Pu, Pei‐Pei Xie, Ya-Qing Chen et autres