Showing papers by "Hermann Kolanoski published in 1989"
Technical University of Dortmund1, University of Erlangen-Nuremberg2, Heidelberg University3, Natural Sciences and Engineering Research Council4, National Science Foundation5, Karlsruhe Institute of Technology6, University of Ljubljana7, Swedish Research Council8, United States Department of Energy9
TL;DR: In this paper, the ARGUS detector at the e+e− storage ring DORIS II at DESY was used to study the γγ→ϱ+ϱ−→π+π−π 0π0π0 reaction.
91 citations
RWTH Aachen University1, University of Bonn2, Science and Engineering Research Council3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this paper, the authors studied the effect of time-intermittency effects in e + e − annihilation, using 37 509 hadronic events at an average CM energy of 〈√ s 〉=35 GeV.
90 citations
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this article, the multiplicity distributions of charged particles produced ine+e− annihilation into hadrons at c.m. energies between 14 and 46.8 GeV were analyzed.
Abstract: We report on an analysis of the multiplicity distributions of charged particles produced ine+e− annihilation into hadrons at c.m. energies between 14 and 46.8 GeV. The charged multiplicity distributions of the whole event and single hemisphere deviate significantly from the Poisson distribution but follow approximate KNO scaling. We have also studied the multiplicity distributions in various rapidity intervals and found that they can be well described by the negative binomial distribution only for small central intervals. We have also analysed forward-backward multiplicity correlations for different energies and selections of particle charge and shown that they can be understood in terms of the fragmentation properties of the different quark flavours and by the production and decay of resonances. These correlations are well reproduced by the Lund string model.
89 citations
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this paper, the authors measured π± and K± mesons and of protons and antiprotons ine+e− annihilations at 34 GeV and 44 GeV center of mass energy.
Abstract: The inclusive production of π± andK± mesons and of protons and antiprotons ine+e− annihilations has been measured at 34 GeV and 44 GeV center of mass energy; in addition π± mesons have been measured at 44 GeV c.m. energy. Differential cross sections and particle yields are given. At 34 GeV average multiplicities are:
$$\begin{gathered} \left\langle {n\left( {\pi ^ \pm } \right)} \right\rangle = 10.9 \pm 0.5,\left\langle {n\left( {K^ \pm } \right)} \right\rangle = 1.76 \pm 0.20, \hfill \\ \left\langle {n\left( {p + \bar p} \right)} \right\rangle = 0.67 \pm 0.06 \hfill \\ \end{gathered} $$
and at 44 GeV:
$$\left\langle {n\left( {\pi ^ \pm } \right)} \right\rangle = 11.1 \pm 0.5,\left\langle {n\left( {\pi ^0 } \right)} \right\rangle = 5.4 \pm 1.0.$$
59 citations
Technical University of Dortmund1, University of Erlangen-Nuremberg2, Heidelberg University3, Natural Sciences and Engineering Research Council4, National Science Foundation5, Karlsruhe Institute of Technology6, University of Ljubljana7, Swedish Research Council8, United States Department of Energy9
TL;DR: In this article, the average polarization of D∗+ mesons originating from exclusive decays B 0 → D ∗+ l − ν was measured using the ARGUS detector at the e+e− storage ring DORIS II.
45 citations
TL;DR: Using the ARGUS detector at the DORIS II storage ring at DESY, a charmed meson of mass (2455±3±5) MeV/c2, decaying to D+π− was observed in this paper.
41 citations
Technical University of Dortmund1, University of Erlangen-Nuremberg2, Heidelberg University3, Max Planck Society4, Natural Sciences and Engineering Research Council5, National Science Foundation6, Karlsruhe Institute of Technology7, University of Ljubljana8, Swedish Research Council9, United States Department of Energy10
TL;DR: In this paper, a decay angular analysis of the D∗ (2420), seen in the final state D ∗(2010)+π−, was performed using data collected with the ARGUS detector.
34 citations
TL;DR: Using the ARGUS detector at the e + e − storage ring DORIS II, this article investigated the decay B 0 → D − l + ν, where l + is e + or μ +.
33 citations
TL;DR: Using the ARGUS detector at the storage ring DORIS II, this article investigated the inclusive production of π±,K€�€£€�£££ £££▬▬▬▬▬▬▬ in multihadron events at 9.98 GeV and in direct decays of the ϒ(1S) meson from quark and gluon fragmentation.
Abstract: Using the ARGUS detector at thee
+
e
− storage ring DORIS II, we have investigated inclusive production of π±,K
±,K
and
$$\bar p$$
in multihadron events at 9.98 GeV and in direct decays of the ϒ(1S) meson, i.e. from quark and gluon fragmentation. The most pronounced difference is the rate of baryon production. The Lund Monte Carlo program gives a reasonable qualitative description, although it cannot reproduce our data in detail.
30 citations
TL;DR: Using the ARGUS detector at the DORIS II e + e − storage ring at DESY, the authors obtained evidence for a new charmed-strange meson which decays into D *+ K 0.
22 citations
Technical University of Dortmund1, University of Erlangen-Nuremberg2, Heidelberg University3, Max Planck Society4, Natural Sciences and Engineering Research Council5, National Science Foundation6, Karlsruhe Institute of Technology7, University of Ljubljana8, Swedish Research Council9, United States Department of Energy10
TL;DR: Using the ARGUS detector at the DORIS II e+e- storage ring at DESY, this article observed a new charmed meson of mass (2469±4±6) MeV/c2, decaying to D0π+.
Technical University of Dortmund1, University of Erlangen-Nuremberg2, Heidelberg University3, Max Planck Society4, Natural Sciences and Engineering Research Council5, National Science Foundation6, Karlsruhe Institute of Technology7, University of Ljubljana8, Swedish Research Council9, United States Department of Energy10
TL;DR: In this paper, the ARGUS detector at the e+e- storage ring DORIS II was used to determine the ratio of semileptonic branching ratios of B+ and B0 mesons.
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Queen Mary University of London9, Rutherford Appleton Laboratory10, Weizmann Institute of Science11, University of Wisconsin-Madison12
TL;DR: In this article, the properties of the associated jets are studied, with comparisons made between them and those in hadronic data in which b quarks make up only 10% of the total, and jets in Monte Carlo events.
Abstract: Ab enrichment technique using the longB lifetime has been developed, by which ∼600 hadronic events with >65%b purity are obtained. The properties of the associated jets are studied, with comparisons made between them and those in hadronic data in whichb quarks make up only 10% of the total, and jets in Monte Carlo events. The distributions in rapidity and multiplicity yield two new determinations of the fragmentation variablez forb hadrons and confirm that theb fragmentation function is hard. We also present the first measurement of the relative strength of the strong interaction coupling of theb quark compared with the average of all flavours.
10 Nov 1989-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, a micro-vertex drift chamber (μVDC) is proposed for B-meson physics at DORIS energies, which is optimized for minimal multiple scattering for low-momentum particles and three-dimensional reconstruction of decay vertices with equal resolutions in r - φ and r - z.
Abstract: The ARGUS collaboration is currently building a new microvertex drift chamber (μVDC) as an upgrade of their detector. The μVDC is optimized for B-meson physics at DORIS energies. Important design features are minimal multiple scattering for low-momentum particles and three-dimensional reconstruction of decay vertices with equal resolutions in r - φ and r - z . Vertex resolutions of 15–25 μm are expected. Prototypes of the μVDC have been tested with different gas mixtures at various pressures. Spatial resolutions as small as 20 μm were obtained using CO 2 /propane at 4 bar and DME at 1 bar. New readout electronics have been developed for the μVDC aiming at low thresholds for the TDC measurements. Employing a novel idea for noise and cross-talk suppression, which is based on a discrimination against short pulses, very low threshold settings are possible.
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this paper, data on jet masses, resulting from the decomposition of hadronic final states into two hemispheres, are presented at the center of mass energies between 12 and 43.5 GeV.
Abstract: Data on jet masses, resulting from the decomposition ofe
+
e
− hadronic final states into two hemispheres, are presented at centre of mass energies between 12 and 43.5 GeV. Comparisons are made with bareO(α
2
) QCD predictions as well as with QCD based fragmentation models. Values for α
s
and
$$\Lambda _{\overline {MS} } $$
are determined, both with and without hadronization effects included. Upper and lower limits for
$$\Lambda _{\overline {MS} } $$
independent of fragmentation models have been determined to be 0.480±0.025 GeV and 0.047±0.007 GeV respectively.
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this paper, the particle fractional momentum distribution for gluon jets is extracted by comparing two data samples measured in the TASSO detector: nearly symmetric three jet events at centre-of-mass energyW∼35 GeV and two jet event at W∼22 GeV.
Abstract: Inclusive charged particle production ine
+
e
− annihilation into hadrons is studied in terms of the particle fractional momentumx
p
. Thex
p
distribution for gluon jets is extracted by comparing two data samples measured in the TASSO detector: nearly symmetric three jet events at centre-of-mass energyW∼35 GeV and two jet events atW∼22 GeV, yielding quark and gluon jets of similar energies (∼11.5 GeV). No significant difference is observed between quark and gluon jets. Monte Carlo models based on parton showers describe the trend and energy variation of the data better than a model with second order matrix element in α
s
.
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Queen Mary University of London9, Rutherford Appleton Laboratory10, Weizmann Institute of Science11, University of Wisconsin-Madison12
TL;DR: In this article, the authors studied the production of strange baryons at the center of mass energies of 34.8 GeV and 42.1 GeV, using the TASSO detector at DESY.
Abstract: The production of strange baryons ine
+
e
− annihilation has been studied at centre of mass energies of 34.8 GeV and 42.1 GeV, using the TASSO detector at DESY. Inclusive cross-sections have been obtained forΛ
0 andΞ
− production and an upper limit has been placed upon the production rate of Σ*±(1385). We measure theΛ
0 multiplicity per event to be
$$\begin{gathered} \hfill \\ 0.218_{ - 0.011}^{ + 0.011} \pm 0.021 \hfill \\ \end{gathered} $$
and
$$0.256_{ - 0.029}^{ + 0.030} \pm 0.025$$
at
$$\sqrt s = 34.8$$
and 42.1 GeV respectively. The Ξ− multiplicity per event is found to be
$$0.014_{ - 0.003}^{ + 0.003} \pm 0.004$$
at
$$\sqrt s = 34.8 GeV$$
. An investigation has been made of the extent to whichΛ
0 are produced in pairs. TheΛ
0 cross-section has been studied as a function of event sphericity.
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this article, the authors report on a study of inclusive production of mesons ine−− annihilation at c.m. energies between 28 and 46.8 GeV using the TASSO detector at PETRA storage ring.
Abstract: We report on a study of inclusive production ofD
*± mesons ine
+
e
− annihilation at c.m. energies between 28 and 46.8 GeV using the TASSO detector at the PETRA storage ring. A hardD
*± energy spectrum is measured with a maximum nearE
D
*±
≃0.6E
beam. The measured cross section ratio
$$(\sigma _{D^{* + } } + \sigma _{D^{* - } } )/\sigma _{\mu \mu } = 1.28 \pm 0.09 \pm 0.18$$
indicates thatD
* production accounts for a large fraction of the observed charm production. Two complementary methods have been used to determine the forward-backward asymmetry of charm pair production due to electroweak interference. Combining both measurements the product of the axial vector couplings of the electron and the charm quark to the weak neutral current was determined to beg
A
e
g
A
c
=−(0.276±0.073), in agreement with the standard model prediction of −0.25. Using a sample of reconstructedD
*± mesons, the relative strength of the strong interaction coupling of thec quark compared to that of an average of all flavours is measured as αs(c)/αs(all)=0.91±0.38±0.15, consistent with the coupling constant being flavour independent. An update of ourD
0 lifetime measurement is presented, based on a considerable increase in statistics, the final result being
$$\tau _{D^0 = } (4.8 \pm _{0.9 - 0.7}^{1.0 + 0.5} )10^{ - 13} s$$
.
TL;DR: In this paper, a high precision measurement of ϕ-meson production in continuum events and in direct decays of the Υ(1S)- and Υ (2S)-mesons is reported.
Abstract: We report on a high precision measurement of ϕ-meson production in continuum events and in direct decays of the Υ(1S)- and Υ(2S)-mesons. The ratio of the total production rate of ϕ-mesons in direct Υ(1S)- and Υ(2S)-decays over that in continuum events is 1.32±0.08±0.09 and 1.07±0.13±0.11 respectively. This is compatible with the corresponding ratio obtained for lighter mesons, but is appreciably smaller than the relative baryon production rate.
TL;DR: In this article, the decay of baryons into the p, Λ and Ξ− has been studied, and the measured inclusive branching ratios for these decays are Br(B→p X) =(8.2±0.5−1.3)%, Br(b→ΛX)=(4.0+1.5± 0.6)% and Br(p→Ξ−X)<0.51% at the 90% confidence level.
Abstract: The decay ofB mesons into the baryonsp, Λ andΞ− has been studied. The measured inclusive branching ratios for these decays are Br(B→p X) =(8.2±0.5−1.0+1.3)%, Br(B→ΛX)=(4.2±0.5±0.6)% and Br(B→Ξ−X)<0.51% at the 90% confidence level. In addition investigations onp\(\bar p\), andΛ\(\bar p\) andΛ\(\bar \Lambda \) correlations were performed, yielding an approximately equal rate of protons and neutrons. From this one can derive a total baryonic branching ratio Br(B→baryons) of (7.6±1.4)%.
TL;DR: The correlations between point-like diquark-antidiquark pairs and baryons have been measured ine + e − continuum events and in direct Ψ decays as mentioned in this paper.
Abstract: The correlations betweenp \(\bar p\),\(\Lambda \bar \Lambda \),\(\Xi ^ - \bar \Lambda \) and\(\Lambda (1520)\bar \Lambda \) baryons have been measured ine + e − continuum events and in direct Ψ decays The observed correlations exclude the production of point-like diquark-antidiquark pairs as the dominant source of baryons Information concerning angular momentum compensation follows from the observed\(\Lambda (1520)\bar \Lambda \) correlation
TL;DR: In this article, the ARGUS detector at DESY has been used to investigate two-photon production of the exclusive final statesp\(\bar p\)+nπ (n=0, 1, 2, and 3).
Abstract: Two-photon production of the exclusive final statesp\(\bar p\)+nπ (n=0, 1, 2, and 3) has been investigated using the ARGUS detector at thee+e− storage ring DORIS II at DESY. The reactionsγγ→p\(\bar p\)π andγγ→p\(\bar p\)π+π−π0 have been observed for the first time, as have theΔ++ and\(\overline {\Delta ^{ + + } } \) baryons in the final statep\(\bar p\)π+π−. No evidence was found forΔ++\(\overline {\Delta ^{ + + } } \) production. Topological cross sections for two-photon production ofp\(\bar p\),p\(\bar p\)π0,p\(\bar p\)π+π− andp\(\bar p\)π+π−π0, as well as the crosssection forγγ→Δ++\(\bar p\)π+π−+c.c., have been measured. Upper limits are given for the cross section forγγ→Δ0\(\overline {\Delta ^0 } \),γγ→Δ++\(\overline {\Delta ^{ + + } } \) andγγ→Λ\(\bar \Lambda \).
TL;DR: In this article, the ARGUS detector at the DORIS II storage ring has searched for radiative decays Υ(1S)→γX, whereX decays into two oppositely charged pions, kaons, or protons.
Abstract: Using the ARGUS detector at the DORIS II storage ring we have searched for radiative decays Υ(1S)→γX, whereX decays into two oppositely charged pions, kaons, or protons. Upper limits on branching fractions are presented. In the π+π- invariant mass region 290–570 MeV/c2 the upper limit obtained varies from 3 to 4.5×10−5. These values are lower than the theoretical prediction of about 5×10−5 for Higgs production, which includes perturbative QCD radiative corrections to the Wilczek formula and the estimate Br(H
0→π+π-), accounting for Higgs coupling to gluons via heavy quark loops. Previous experimental results do not exclude the existence of a standard minimal Higgs in this mass region.
TL;DR: In this paper, the ARGUS detector at DORIS II was used to detect Δ(1232) ++ and Δ ( 1232 ) + + ¯ baryons in e + e − annihilation at energies around 10 GeV.
RWTH Aachen University1, University of Bonn2, University of Bristol3, Technical University of Dortmund4, University of Hamburg5, Imperial College London6, Autonomous University of Madrid7, University of Oxford8, Rutherford Appleton Laboratory9, Weizmann Institute of Science10, University of Wisconsin-Madison11
TL;DR: In this paper, the authors used the known γγγγ(η====== c¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ c>>\s ) branching ratio to obtain an upper bound on the width of the signal in two decay modes with a combined statistical significance of 3.5 standard deviations.
Abstract: Production of theη
c
meson ine
+
e
− quasireal two photon collisions has been looked for in three channels. The data were obtained from an integrated luminosity of 189 pb−1. Anη
c
signal is observed in two decay modes (K
0
K
±π∓,π+π-π+π-) with a combined statistical significance of 3.5 standard deviations. Using the knownη
c
branching ratios to these channels and toK
+
K
-π+π- the combined partialη
c
width to γγ isΓ
γγ(η
c
). The first error is statistical, and the second one includes the systematic and branching ratio errors. Calculated as an upper limit we obtainΓ
γγ(η
c
) (95% C.L., including the systematic error).
TL;DR: In this article, the authors report on total cross section and forward backward charge asymmetry measurements of leptonic reaction at center of mass energies of 35.0 GeV and 42.4 GeV using the TASSO detector.
Abstract: We report on total cross section and forward backward charge asymmetry measurements of the reactione
+
e
− → τ+τ− at centre of mass energies of 35.0 GeV and 42.4 GeV using the TASSO detector. Including previous data an analysis in terms of electroweak parameters of the standard model is presented, and lower limits on mass scale parameters of residual contact interactions are given. A combined analysis of electroweak couplings using all our results on leptonic reactionse
+
e
−→l
+
l
− has been performed.
TL;DR: In this article, the branching ratio of the D petertodd0 meson decays into the Kπ−π+ mode using the ARGUS detector at the electron-positron storage ring DORIS II.
Abstract: Using the ARGUS detector at the electron-positron storage ring DORIS II at DESY, we have measured the branching ratios of theD
0 meson decays into
$$\overline {K^0 } \omega $$
,
$$\overline {K^0 } \eta $$
and
$$\overline {K^{*0} } \eta $$
relative to theK
−π+ mode. Using the known branching ratio Br(D
0→Kπ+)=(4.2±0.4±0.4)% we find
$$Br(D^0 \to \overline {K^0 } \omega ) = (4.2 \pm 1.6 \pm 0.9)\% ,Br(D^0 \to \overline {K^0 } \eta )< 2.7\% $$
(90% CL) and
$$Br(D^0 \to \overline {K^{*0} } \eta )< 2.9\% $$
(90% CL).
01 Jun 1989
TL;DR: The contribution of two-photon physics to meson spectroscopy are first of all the measured γγ widths in Table 1 as discussed by the authors, and conclusions and conclusions can be summarized as follows: • • Pseudoscalars: the pseudoscalar mixing angle is φp = (−22.2 ± 1.2)°; non-q q admixtures, like gluonium, are not needed; no other light 0− states, like radial excitations, are observed.
Abstract: The contributions of two-photon physics to meson spectroscopy are first of all the measured γγ widths in Table 1. Further results and conclusions can be summarized as follows: • • Pseudoscalars: the pseudoscalar mixing angle is φp = (−22.2 ±1.2)°; non -q q admixtures, like gluonium, are not needed; no other light 0− states, like radial excitations, are observed; the measured γγ width of the ηc is consistent with the charmonium model. • • Tesor Mesons: Well measured, well understood multiplet; mixing angle ≈ 28°. • • Axial vectors: φ1(1285) and φ1(1420) could be members of the same nonet with mixing angle 45–57°; an exotic explanation is not required by the γγ data. • • Scalar Mesons: the measured γγ width of α0(980) and φ0(975) are smaller than expected for q q states, but consistent with four-quark or K K molecule models; no other I=0 state has been observed. • • D-wave q q (2 −+ ): γγ → π 2 (1680) → π 0 π 0 π 0 observed, Γγγ = (1.4±0.3) keV. • • Glueballs: Non-observation of η(1440), φ2(1720) in γγ rreactions supports glueball hypotheses. • • Vector meson pairs: All channels involving ϱ,ω,φ,K ∗ are studied; contributions from four-quark states not yet clear; no other good explanation for γγ → ϱϱ near threshold.