Showing papers by "M. Holder published in 1989"
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
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.
16 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, 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.
13 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, 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.
13 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 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
.
13 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 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
$$\tau _{D^0 = } (4.8 \pm _{0.9 - 0.7}^{1.0 + 0.5} )10^{ - 13} s$$
.
13 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 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).
5 citations
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.
3 citations
01 Jan 1989
TL;DR: In this article, the authors presented their work supported in part by the US Department of Energy contract DE-AC03-765F0051515 and the German Federal Minister for Research and Technology (BMFT) under contract 054 Si74.
Abstract: Present address: Fachbereich Physik, Universit~it Siegen, D-5900 Siegen 21, Fed. Rep. Germany. 2 On leave from SLAC, Stanford, CA 94305, USA. 3 Work supported in part by the US Department of Energy contract DE-AC03-765F00515. 4 Present address: Scuola Normale Superiore e Sezione INFN, 1-56100 Pisa, Italy. 5 Present address: DVFLR, D-5000 Cologne, Fed. Rep. Germany. 6 Present address: LAL, Universit6 Paris-Sud, F-91405 Orsay, France. 7 Present address: II. Institut f'tir experimentelle Physik, Universit~it Hamburg, D-2000 Hamburg, Fed: Rep. Germany. 8 Present address: IP-Systems, D-7500 Karlsruhe, Fed. Rep. Germany. 9 Funded by the German Federal Minister for Research and Technology (BMFT) under contract 05 4MZ18, ~o Present address: FWI, University of Amsterdam, 1018 XE Amsterdam, The Netherlands. ~ Present address: Syracuse University, Syracuse, NY 13244-1130, USA. ~2 Funded by Institut National de Physique des Particules et de Physique Nucl6aire, France. 13 Present address: Dipartimento di Fisica e Sezione INFN, 1-06100 Perugia, Italy. J4 Funded by the German Federal Minister for Research and Technology (BMFT) under contract 054 Si74.