Showing papers by "Hermann Kolanoski published in 1980"

Observation of an eta/sub c/ candidate state with mass 2978 +- 9 MeV

Abstract: An ${\ensuremath{\eta}}_{c}$ candidate state has been observed with a mass $M=2978\ifmmode\pm\else\textpm\fi{}9$ MeV and a natural line width $\ensuremath{\Gamma}l20$ MeV (90% confidence level) using the Crystal Ball NaI(T1) detector at SPEAR. Radiative transitions to this state are observed from ${\ensuremath{\psi}}^{\ensuremath{'}}(3684)$ and $\frac{J}{\ensuremath{\psi}}(3095)$ in the inclusive photon spectra. The branching fraction to this state from the ${\ensuremath{\psi}}^{\ensuremath{'}}$ is (0.43\ifmmode\pm\else\textpm\fi{}0.08\ifmmode\pm\else\textpm\fi{}0.18)%, where the errors are statistical and systematic, respectively. In addition, evidence is presented for the decay of this new state into $\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and an upper limit is presented on the decay into ${\ensuremath{\pi}}^{0}{K}^{+}{K}^{\ensuremath{-}}$.

Measurement of the decays psi'. -->. etaJ/psi and psi'. --> pi. /sup 0/J/psi

Abstract: The Crystal Ball detector at SPEAR has been used to investigate the decays psi'..-->..etaJ/psi and psi'..--> pi../sup 0/J/psi resulting from production of 776 000 psi'. Our measurement for the branching ratio of the eta mode is (2.18 +- 0.14 +- 0.35)%, where the first error results from statistics and acceptance uncertainties, and the second error is systematic; this is almost a factor of 2 smaller than found in early experiments. For the isospin-nonconserving ..pi../sup 0/ mode, a branching ratio (0.09 +- 0.02 +- 0.01)% is obtained.

DecayJψ→3γand a Search for theηc

Abstract: The decay $\frac{J}{\ensuremath{\psi}}$ into $3\ensuremath{\gamma}$ final states has been studied. No evidence is found for the existence of the $X(2.83)$ or any heavy narrow state (e.g., the ${\ensuremath{\eta}}_{c}$) decaying into two photons. Upper limits are given on the branching ratio $\frac{J}{\ensuremath{\psi}}\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}$, ${\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}2\ensuremath{\gamma}$ for ${\ensuremath{\eta}}_{c}$ masses in the 2.7-3.0-GeV region. In addition, the branching ratios $\frac{J}{\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\eta}}$, $\ensuremath{\gamma}{\ensuremath{\eta}}^{\ensuremath{'}}$ are measured. It is found that the ${\ensuremath{\eta}}^{\ensuremath{'}}$ branching ratio is higher than previously reported.

Two photon results from TASSO

Abstract: Two photon annihilation processes were observed with the TASSO detector at the e+e- storage ring PETRA. We report on the analyses of untagged and single tag events.

Recent results from the crystal ball detector at SPEAR

Abstract: Evidence for an ηc candicate with a mass of 2980±15 MeV from the ψ′ inclusive γ spectrum is presented. The corresponding region in the J/ψ inclusive γ spectrum is then studied and shown to be consistent with a broad Breit‐Wigner enhancement superimposed upon a smooth background. Results from a detailed study of the two exclusive decay modes ψ′→γγ ψ→γγ e+e− and ψ′→γγ ψ→γγμ+μ− are also given. These consist of measurements of the cascade branching ratios BR(ψ′→γχ→γγψ) for χ(3.55) and χ(3.51) and upper limits on this branching ratio for χ(3.41), χ(3.45), and χ(3.59). Finally, we give branching ratios for the two decays ψ′→ηψ and ψ′→π °ψ.