Showing papers by "Hermann Kolanoski published in 1986"
TL;DR: In this article, a detailed study using the crystal ball detector at the SLAC (e}+}$${e}^{\mathrm{\ensuremath{-}}}$ storage ring SPEAR of the inclusive photon spectra from 1.8 to 2.5 MeV is presented.
Abstract: Results from a detailed study using the Crystal Ball detector at the SLAC ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ storage ring SPEAR of the inclusive photon spectra from 1.8\ifmmode\times\else\texttimes\fi{}${10}^{6}$ \ensuremath{\psi}' and 2.2\ifmmode\times\else\texttimes\fi{}${10}^{6}$ J/\ensuremath{\psi} decays are presented. Radiative transitions from the \ensuremath{\psi}' to the ${\ensuremath{\chi}}_{2}$,1,0 states are observed with photon energies of 126.0\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\fi{}4, 169.6\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\pm\else\textpm\fi{}4, and 258.4\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}4 MeV and branching ratios B(\ensuremath{\psi}'\ensuremath{\rightarrow}\ensuremath{\gamma}${\ensuremath{\chi}}_{2}$,1,0) =(8.0\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.7)%, (9.0\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.7)%, and (9.9\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}0.8)%, respectively. Values for the natural linewidths of the \ensuremath{\chi} states are obtained: \ensuremath{\Gamma}(${\ensuremath{\chi}}_{2}$,1,0)=0.8--4.9, l3.8, and 13--21 MeV, respectively (90% C.L.). Improved values are found for the branching ratios B(\ensuremath{\psi}'\ensuremath{\rightarrow}\ensuremath{\gamma}${\ensuremath{\eta}}_{c}$) =(0.28\ifmmode\pm\else\textpm\fi{}0.06)% and B(J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}${\ensuremath{\eta}}_{c}$)=(1.27\ifmmode\pm\else\textpm\fi{}0.36)%, and for the natural width \ensuremath{\Gamma}(${\ensuremath{\eta}}_{c}$)=11.5\ifmmode\pm\else\textpm\fi{}4.5 MeV.
81 citations
RWTH Aachen University1, University of Bonn2, University of Bristol3, University of Hamburg4, Imperial College London5, Autonomous University of Madrid6, University of Oxford7, Queen Mary University of London8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this article, Bose-Einstein correlations between pairs of charged particles produced ine+e− annihilation into hadronic final states have been studied as a function of Q2, the relative momentum squared of the two particles in their centre of mass, and as functions of various pairs of kinematic variables.
Abstract: Bose-Einstein correlations between pairs of charged particles produced ine+e− annihilation into hadronic final states have been studied as a function ofQ2, the relative momentum squared of the two particles in their centre of mass, and as functions of various pairs of kinematic variables. The observed Bose-Einstein enhancement reveals correlation between the position and time of particle emission, and the space-time structure of the source is shown to differ from that of a pion fireball. While most features of the data are well accounted for in terms of the space-time structure of a simple string model, the correlations are better described by the simple function 1+αe−βQ2. The implications of this result are discussed. The principal features of three particle correlations are explained in terms of the structure of the source inferred from the observed two particle correlations.
32 citations
RWTH Aachen University1, University of Bonn2, University of Bristol3, University of Hamburg4, Imperial College London5, Autonomous University of Madrid6, University of Oxford7, Queen Mary University of London8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this article, the photon structure function was determined at an average q2 of 23 (GeV/c)2 with statistical and systematic uncertainties, where the errors include statistical, systematic, and higher order corrections.
Abstract: We have measured the processe
+
e
−→e
+
e
−+hadrons, where one of the scattered electrons was detected at large angles, withQ
2 ranging from 7 to 70 (VeV/c)2. The photon structure functionF
2
γ
(x, Q2) was determined at an averageQ
2 of 23 (GeV/c)2. The measurements were compared to theoretical predictions of the Quark Parton Model and Quantum Chromodynamics. In both models a hadronic part was added. Within the errors the data are in agreement with the QPM using quark masses of 300 MeV/c2 for the light quarks. The data also agree with a QCD calculation including higher order corrections. A fit yielded a
$$\Lambda _{\overline {MS} } $$
value of 140
−65
+190
MeV, where the errors include statistical and systematic uncertainties.
28 citations
RWTH Aachen University1, University of Bonn2, University of Bristol3, University of Hamburg4, Imperial College London5, Autonomous University of Madrid6, University of Oxford7, Queen Mary University of London8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this article, a clear Φ(1020) signal is seen in the K+K− mass distribution and a K*0 signal is visible in the k±π∓ one.
Abstract: Vector meson production is studied in the reaction γγ→K+K−π+π−. A clear Φ(1020) signal is seen in theK+K− mass distribution and aK*0 (890) signal is visible in theK±π∓ one. Both do not seem to be strongly correlated with quasi two body final states. Cross sections for the processes γγ→K+K−π+π−, γγ→Φπ+π−, γγ→K+0K±π∓ and upper limits for the production of Φp, ΦΦ andK*0\(\overline {K^{ * 0} } \) are given as function of the invariant γγ mass.
15 citations
TL;DR: In this article, the angular distribution for π 0 energies larger than 2 GeV is of the formdσ/dΩ∼1+Acos2θ, withA=1.13±0.18 The form of the differential cross sections agrees within the errors.
Abstract: The cross section for the processe
+
e
−→π0+ anything has been measured at an average center of mass energy of 34.6 GeV for π0 energies between 0.7 and 17 GeV. The angular distribution for π0 energies larger than 2 GeV is of the formdσ/dΩ∼1+Acos2θ, withA=1.2±0.5. The ratio of π0 to π± production in the measured energy range is 2σ(π0)/(σ(π+)+σ(π−))=1.13±0.18 The form of the differential cross sections agrees within the errors. The mean π0 multiplicity is 5.8±0.9.
11 citations
Journal Article•
7 citations
RWTH Aachen University1, University of Bonn2, University of Bristol3, University of Hamburg4, Imperial College London5, Autonomous University of Madrid6, University of Oxford7, Queen Mary University of London8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this article, the reactione+e−→e+ e− A2 (1320) has been observed by detecting the decayA2→π+π-π0, and the two-photon width of the A2 has been measured to be Г(A2) = 0.09±0.27 (stat)± 0.16 (syst)) keV.
Abstract: The reactione+e−→e+e− A2 (1320) has been observed by detecting the decayA2→π+,π-π0. The two-photon width of theA2 has been measured to be Г(A2→γγ)=(0.09±0.27 (stat)±0.16 (syst)) keV. The cross section σ(γγ→π+,π-π0 has been determined outside theA2 resonance region.
6 citations
RWTH Aachen University1, University of Bonn2, University of Bristol3, University of Hamburg4, Imperial College London5, Autonomous University of Madrid6, University of Oxford7, Queen Mary University of London8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this article, the authors determined theD0 lifetime from reconstructed vertices of D0 mesons produced ine+e− annihilations at an average center of mass energy of 42.2 GeV.
Abstract: We have determined theD0 lifetime from reconstructed vertices ofD0 mesons produced ine+e− annihilations at an average center of mass energy of 42.2 GeV. From fifteen events theD0 lifetime was determined to be (4.3−1.4+2.0±0.8)×10−13s.
4 citations