arXiv subjects

The BES Collaboration

Publications and source records attributed to The BES Collaboration.

7 recordsLinked to original sources

arXiv2009

Study of J/Psi decays into eta Kstar Kstar-bar

We report the first observation of $\mPJpsi \to \mPeta\mPKst\mAPKst$ decay in a $\mPJpsi$ sample of 58 million events collected with the BESII detector. The branching fraction is determined to be $(1.15 \pm 0.13 \pm 0.22)\times 10^{-3}$. The selected signal event sample is further used to search for the $\mPY$ resonance through $\mPJpsi \to \mPeta \mPY, \mPY\to\mPKst\mAPKst$. No evidence of a signal is seen. An upper limit of \mathrm{Br}(\mPJpsi \to \mPeta \mPY)\cdot\mathrm{Br}(\mPY\to\mPKst\mAPKst) < 2.52\times 10^{-4} is set at the 90% confidence level.

hep-ex↗

arXiv2009

$R$ value measurements for $e^+e^-$ annihilation at 2.60, 3.07 and 3.65 GeV

Using a data sample with a total integrated luminosity of 10.0 pb$^{-1}$ collected at center-of-mass energies of 2.6, 3.07 and 3.65 GeV with BESII, cross sections for $e^+e^-$ annihilation into hadronic final states ($R$ values) are measured with statistical errors that are smaller than 1%, and systematic errors that are about 3.5%. The running strong interaction coupling constants $α_s^{(3)}(s)$ and $α_s^{(5)}(M_Z^2)$ are determined from the $R$ values.

hep-ex↗

arXiv2007

Experimental studies of the $π^+π^-π^+π^-π^0$, $K^+K^-π^+π^-π^0$ and $p\bar pπ^+π^-π^0$ final states produced in $e^+e^-$ annihilation at $\sqrt{s}=$ 3.773 and 3.650 GeV

We report measurements of the observed cross sections for $e^+e^-\toωπ^+π^-$, $ωK^+K^-$, $ωp\bar p$, $K^+K^-ρ^0π^0$, $K^+K^-ρ^+π^-+c.c.$, $K^{*0}K^-π^+π^0+c.c.$, $K^{*+}K^-π^+π^-+c.c.$, $ϕπ^+π^-π^0$ and $Λ\bar Λπ^0$ at $\sqrt s=$ 3.773 and 3.650 GeV. Upper limits (90% C.L.) are given for observed cross sections and for $ψ(3770)$ decay branching fractions for production of these final states. These measurements are made by analyzing the data sets of 17.3 pb$^{-1}$ collected at $\sqrt{s}=3.773$ GeV and 6.5 pb$^{-1}$ collected at $\sqrt{s}=3.650$ GeV with the BES-II detector at the BEPC collider.

hep-ex↗

arXiv2007

Measurements of the observed cross sections for exclusive light hadron production in e^+e^- annihilation at \sqrt{s}= 3.773 and 3.650 GeV

By analyzing the data sets of 17.3 pb$^{-1}$ taken at $\sqrt{s}=3.773$ GeV and 6.5 pb$^{-1}$ taken at $\sqrt{s}=3.650$ GeV with the BESII detector at the BEPC collider, we have measured the observed cross sections for 12 exclusive light hadron final states produced in $e^+e^-$ annihilation at the two energy points. We have also set the upper limits on the observed cross sections and the branching fractions for $ψ(3770)$ decay to these final states at 90% C.L.

hep-ex↗

arXiv2007

Measurements of psi(2S) decays to octet baryon-antibaryon pairs

With a sample of 14 million psi(2S) events collected by the BESII detector at the Beijing Electron Positron Collider (BEPC), the decay channels psi(2S)->p p-bar, Lambda Lambda-bar, Sigma0 Sigma0-bar, Xi Xi-bar are measured, and their branching ratios are determined to be (3.36+-0.09+-0.24)*10E-4, (3.39+-0.20+-0.32)*10E-4, (2.35+-0.36+-0.32)*10E-4, (3.03+-0.40+-0.32)*10E-4, respectively. In the decay psi(2S)->p p-bar, the angular distribution parameter alpha is determined to be 0.82+-0.17+-0.04.

hep-ex↗

arXiv2006

Search for D to phi l nu and measurement of the branching fraction for D to phi pi

Using a data sample of integrated luminosity of about 33 pb$^{-1}$ collected around 3.773 GeV with the BESII detector at the BEPC collider, the semileptonic decays $D^+ \to ϕe ^+ν_e$, $D^+ \to ϕμ^+ν_μ$ and the hadronic decay $D^+ \to ϕπ^+$ are studied. The upper limits of the branching fractions are set to be $BF(D^+ \to ϕe ^+ν_e) <$ 2.01% and $BF(D^+ \to ϕμ^+ ν_μ) <$ 2.04% at the 90% confidence level. The ratio of the branching fractions for $D^+ \to ϕπ^+$ relative to $D^+ \to K^-π^+π^+$ is measured to be $0.057 \pm 0.011 \pm 0.003$. In addition, the branching fraction for $D^+ \to ϕπ^+$ is obtained to be $(5.2 \pm 1.0 \pm 0.4) \times 10^{-3}$.

hep-ex↗

arXiv2005

Search for psi(3770)\raρπat the BESII detector at the Beijing Electron-Positron Collider

Non-$D\bar{D}$ decay $\psppto \rhopi$ is searched for using a data sample of $(17.3\pm 0.5) pb^{-1}$ taken at the center-of-mass energy of 3.773 GeV by the BESII detector at the BEPC. No $\rhopi$ signal is observed, and the upper limit of the cross section is measured to be $σ(\EETO \rhopi)<6.0 pb$ at 90% C. L. Considering the interference between the continuum amplitude and the $\pspp$ resonance amplitude, the branching fraction of $\pspp$ decays to $ρπ$ is determined to be $\BR(\pspp\raρπ)\in(6.0\times10^{-6}, 2.4\times10^{-3})$ at 90% C. L. This is in agreement with the prediction of the $S$- and $D$-wave mixing scheme of the charmonium states for solving the ``$\rhopi$ puzzle'' between $\jpsi$ and $\psp$ decays.

hep-ex↗